Autofocus in real time for smart eyeglasses from Finland

Good news! About time that more progress comes to eyeglasses! What about fixing our eye lenses instead of gadgets?

"A Finnish startup is building glasses that automatically adjust your prescription based on what you’re looking at, using eye-tracking sensors and liquid crystals. They are marketing the device as a more flexible alternative to bifocal lenses."

Doomslayer: Progress Roundup - by Malcolm Cochran

“Autofocus” Glasses Can Change Their Lenses in Real Time

‘Autofocus’ glasses can change their lenses in real time

IXI’s autofocusing lenses are almost ready to replace multifocal glasses

The co-founders. Notice they don't wear eyeglasses! 😊

New image sensor breaks optical limits without using lenses resolves sub-micron features at ultralong working distances and reconstructs 3D shapes over centimeter-scale fields

Amazing stuff! This could be a major breakthrough!

"... introducing a breakthrough solution that could redefine optical imaging across science, medicine, and industry.

"At the heart of this breakthrough is a longstanding technical problem," said Zheng. "Synthetic aperture imaging—the method that allowed the Event Horizon Telescope to image a black hole—works by coherently combining measurements from multiple separated sensors to simulate a much larger imaging aperture." ..."

"... Yet despite decades of innovation, a fundamental barrier has persisted: capturing high-resolution, wide-field images at optical wavelengths without cumbersome lenses or strict alignment constraints. ...

The Multiscale Aperture Synthesis Imager (MASI) turns this challenge on its head. Rather than forcing multiple optical sensors to operate in perfect physical synchrony – a task that would require nanometer-level precision – MASI lets each sensor measure light independently and then uses computational algorithms to synchronize the data afterward. ...

akin to having multiple photographers capture the same scene, not as ordinary photos but as raw measurements of light wave properties, and then letting software stitch these independent captures into one ultra-high-resolution image. ...

MASI deviates from conventional optical imaging in two transformative ways. Rather than relying on lenses to focus light onto a sensor, MASI deploys an array of coded sensors positioned in different parts of a diffraction plane. Each captures raw diffraction patterns –essentially the way light waves spread after interacting with an object. These diffraction measurements contain both amplitude and phase information, which are recovered using computational algorithms.

Once each sensor’s complex wavefield is recovered, the system digitally pads and numerically propagates the wavefields back to the object plane. A computational phase synchronization method then iteratively adjusts the relative phase offsets of each sensor’s data to maximize the overall coherence and energy in the unified reconstruction.

This step is the key innovation: by optimizing the combined wavefields in software rather than aligning sensors physically, MASI overcomes the diffraction limit and other constraints imposed by traditional optics.

The result? A virtual synthetic aperture for larger than any single sensor, enabling sub-micron resolution and wide field coverage without lenses. ..."

From the abstract:

"Synthetic aperture imaging has enabled breakthrough observations from radar to astronomy. However, optical implementation remains challenging due to stringent wavefield synchronization requirements among multiple receivers.

Here we present the multiscale aperture synthesis imager (MASI), which utilizes parallelism to break complex optical challenges into tractable sub-problems. MASI employs a distributed array of coded sensors that operate independently yet coherently to surpass the diffraction limit of single receiver. It combines the propagated wavefields from individual sensors through a computational phase synchronization scheme, eliminating the need for overlapping measurement regions to establish phase coherence.
Light diffraction in MASI naturally expands the imaging field, generating phase-contrast visualizations that are substantially larger than sensor dimensions.

Without using lenses, MASI resolves sub-micron features at ultralong working distances and reconstructs 3D shapes over centimeter-scale fields.

MASI transforms the intractable optical synchronization problem into a computational one, enabling practical deployment of scalable synthetic aperture systems at optical wavelengths."

New image sensor breaks optical limits

New Image Sensor Breaks Optical Limits (original news release) "UConn engineers develop new image sensor to achieve 3D microscopic resolution without lenses."

Multiscale aperture synthesis imager (open access)

A bullet cartridge imaged by MASI.
Top: The captured complex electric field contains both amplitude (brightness) and phase (color) information.
Bottom: This data enables 3D reconstruction at micrometer resolution, showing the firing pin impression, a unique marking that can link a bullet casing to a specific gun

Fig. 1: Operating principle and implementation of MASI.

Ultrasmall optical devices rewrite the rules of light manipulation

Good news!

"In the push to shrink and enhance technologies that control light, MIT researchers have unveiled a new platform that pushes the limits of modern optics through nanophotonics, the manipulation of light on the nanoscale, or billionths of a meter.

The result is a class of ultracompact optical devices that are not only smaller and more efficient than existing technologies, but also dynamically tunable, or switchable, from one optical mode to another. Until now, this has been an elusive combination in nanophotonics. ...

CrSBr is a layered quantum material with a rare combination of magnetic order and strong optical response. Central to its unique optical properties are excitons: quasiparticles formed when a material absorbs light and an electron is excited, leaving behind a positively charged “hole.” The electron and hole remain bound together by electrostatic attraction, forming a sort of neutral particle that can strongly interact with light.

In CrSBr, excitons dominate the optical response and are highly sensitive to magnetic fields, which means they can be manipulated using external controls. ...

Because of these excitons, CrSBr exhibits an exceptionally large refractive index that allows researchers to sculpt the material to fabricate optical structures like photonic crystals that are up to an order of magnitude thinner than those made from traditional materials. “We can make optical structures as thin as 6 nanometers, or just seven layers of atoms stacked on top of each other,” ...

And crucially, by applying a modest magnetic field, the MIT researchers were able to continuously and reversibly switch the optical mode. In other words, they demonstrated the ability to dynamically change how light flows through the nanostructure, all without any moving parts or changes in temperature. ..."

From the abstract:

"Central to the field of nanophotonics is the ability to engineer the flow of light through nanoscale structures. These structures often have permanent working spectral ranges and optical properties that are fixed during fabrication.

Quantum materials, with their correlated and intertwined degrees of freedom, offer a promising avenue for dynamically controlling photonic devices without altering their physical structure.

Here we fabricate photonic crystal slabs from CrSBr, a van der Waals antiferromagnetic semiconductor, and demonstrate in situ control over their optical properties.

Leveraging the combination of the exceptionally large refractive index of CrSBr near its excitonic resonances and its tunability via external fields, we achieve precise manipulation of photonic modes at near-visible and infrared wavelengths, showcasing a new paradigm for nanophotonic device design.

The resulting guided resonances of the photonic crystal are tightly packed in the spectrum with very small mode volumes, are highly tunable via external magnetic fields and exhibit high Q factors exceeding 1,200.

These resonances self-hybridize with the excitonic degrees of freedom, resulting in intrinsic strong light–matter coupling.

Our findings underscore the potential of quantum materials for developing in situ tunable photonic elements and cavities."

Ultrasmall optical devices rewrite the rules of light manipulation | MIT News | Massachusetts Institute of Technology "Nanophotonic devices developed at MIT are compact, efficient, reprogrammable, adaptive, and able to dynamically respond to external inputs."

Tunable nanophotonic devices and cavities based on a two-dimensional magnet (no public access)

Tunable Nanophotonic Devices and Cavities based on a Two-Dimensional Magnet (preprint, open access)

This AR headset is changing how surgeons see inside their patients

Good news!

"At the beginning of this year, Ocutrx Technologies introduced DigiLoupes, an AR/XR [augmented/extended reality] headset that contains 3D sensors and a pancake lens that provides high-quality optics and high-resolution imaging in a headset design. ..."

This AR headset is changing how surgeons see inside their patients | ZDNET "What if a headset could make surgery safer, faster, and less physically taxing? Surgeons are embracing DigiLoupes, a powerful new tool combining magnification, AR overlays, and ergonomic design."

DigiLoupes "Bringing traditional loupes into the digital age with DigiLoupes — the ultimate in 8K resolution, magnification, ergonomic comfort, and hands-free control. Ocutrx is redefining the way surgeons see and perform with next-generation digital optical loupes."

Scientists discover laser light can cast a shadow similar to that of a tree on a sunny day

Amazing stuff! Without a shadow of a doubt! 😊

"... In Optica, researchers describe how they used a ruby crystal and specific laser wavelengths to show that a laser beam could block light and create a visible shadow due to a nonlinear optical process. This effect occurs when light interacts with a material in an intensity-dependent way and can influence another optical field. ..."

"... "What's particularly fascinating is how closely this laser shadow behaves like a traditional shadow,"  ..."

From the abstract:

"Light, being massless, casts no shadow; under ordinary circumstances, photons pass right through each other unimpeded. Here, we demonstrate a laser beam acting like an object — the beam casts a shadow upon a surface when the beam is illuminated by another light source. We observe a regular shadow in the sense it can be seen by the naked eye, it follows the contours of the surface it falls on, and it follows the position and shape of the object (the laser beam). Specifically, we use a nonlinear optical process involving four atomic levels of ruby. We are able to control the intensity of a transmitted laser beam by applying another perpendicular laser beam. We experimentally measure the dependence of the contrast of the shadow on the power of the laser beam, finding a maximum of approximately 22%, similar to that of a shadow of a tree on a sunny day. We provide a theoretical model that predicts the contrast of the shadow. This work opens new possibilities for fabrication, imaging, and illumination."

Scientists discover laser light can cast a shadow

uOttawa physicists make laser cast a shadow (original news release)

Shadow of a laser beam (open access) "In a recent study, researchers from the University of Ottawa have demonstrated a remarkable new phenomenon: a laser beam casting a visible shadow."

Fig. 1. Photographic images of the shadow of a laser beam. A high-power green laser beam (the object), travelling through a cube of ruby, is illuminated from the side by blue light.

Metasurface-enhanced camera performs hyperspectral and polarimetric imaging or seeing like a butterfly

Amazing stuff! Could be very useful!

"A team of US-based researchers has developed an inexpensive and ultrathin metasurface that, when paired with a neural network, enables a conventional camera to capture detailed hyperspectral and polarization data from a single snapshot. The innovation could pave the way for significant advances in medical diagnostics, environmental monitoring, remote sensing and even consumer electronics. ...

“The metasurface consists of many such superpixels; the patterns generated by these superpixels are then captured by a conventional camera sensor,” he adds. “Essentially, the metasurface translates information that is normally invisible to the camera into a format it can detect. Each superpixel corresponds to one pixel in the final image, allowing us to obtain not only intensity information but also the spectrum and polarization data for each pixel.” ...

traditional hyperspectral and polarimetric cameras, which often are bulky and expensive to produce, capture either spectral or polarization data, but not both simultaneously. Such systems are also limited in resolution, not easily integrated into compact devices, and typically require complex alignment and calibration. ..."

"... Butterflies can see more of the world than humans, including more colors and the field oscillation direction, or polarization, of light. This special ability enables them to navigate with precision, forage for food and communicate with one another. ...

A machine learning framework, also developed by the team, then decodes this multi-dimensional visual information in real-time on a standard laptop. ...

“We could bring our camera along to the grocery store, take snapshots and assess the freshness of the fruit and vegetables on the shelves before buying,” ...

used to differentiate the material and structural properties of tissues within the body, potentially aiding in the diagnosis of cancerous cells.  ..."

From the abstract:

"Light fields carry a wealth of information, including intensity, spectrum, and polarization. However, standard cameras capture only the intensity, disregarding other valuable information. While hyperspectral and polarimetric imaging systems capture spectral and polarization information, respectively, in addition to intensity, they are often bulky, slow, and costly. Here, we have developed an encoding metasurface paired with a neural network enabling a normal camera to acquire hyperspectro-polarimetric images from a single snapshot. Our experimental results demonstrate that this metasurface-enhanced camera can accurately resolve full-Stokes polarization across a broad spectral range (700 to 1150 nanometer) from a single snapshot, achieving a spectral sensitivity as high as 0.23 nanometer. In addition, our system captures full-Stokes hyperspectro-polarimetric video in real time at a rate of 28 frames per second, primarily limited by the camera’s readout rate. Our encoding metasurface offers a compact, fast, and cost-effective solution for multidimensional imaging that effectively uses information within light fields."

Metasurface-enhanced camera performs hyperspectral and polarimetric imaging – Physics World

Seeing like a butterfly: Optical invention enhances camera capabilities (original news release)

Real-time machine learning–enhanced hyperspectro-polarimetric imaging via an encoding metasurface (open access)

Fig. 1. Conceptual diagram of the proposed HSP camera.

Fig. 2. Design and characterization of the encoding metasurfaces.

Metasurface makes thermal sources emit laser-like light

Amazing stuff!

"... the new metasurface uses a periodic structure with tailored local perturbations to transform ordinary thermal emissions into something more like a laser beam – an achievement heralded as “just the beginning” for thermal radiation control. ...

The final structure was made from silicon and structured as an array of rectangular pillars (for the non-local interactions) interspersed with elliptical pillars (for the asymmetric emission). Using this structure, the team demonstrated coherent directed emission for six different polarizations, at frequencies of their choice. They also used it to send circularly polarized light in arbitrary directions, and to split thermal emissions into orthogonally polarized components travelling in different directions. While this so-called photonic Rashba effect has been demonstrated before in circularly polarized light, the new thermal metasurface produces the same effect for arbitrary polarizations – something not previously thought possible. ..."

"In a groundbreaking advancement, researchers with the CUNY ASRC have experimentally demonstrated that metasurfaces (two-dimensional materials structured at the nanoscale) can precisely control the optical properties of thermal radiation generated within the metasurface itself. ...

Metasurfaces offer a solution for greater utility by controlling electromagnetic waves through meticulously engineered shapes of nanopillars that are arrayed across their surfaces. By varying these structures, researchers can achieve control over light scattering, effectively “shaping” light in customizable ways. ...

While conventional thermal radiation is unpolarized, a significant focus of the research was enabling thermal radiation with circularly polarized light, where the electric field oscillates in a rotating manner. Recent works had shown that opposite circular polarizations (rotating respectively with left-handed and right-handed features) could be split into opposite directions, but there seemed to be a fundamental limit to further control the polarization of emitted light. The team’s new design transcends this limitation, allowing for asymmetric emission of circular polarization towards a single direction, demonstrating full control over thermal emission. ..."

From the abstract:

"Thermal emission from a hot body is inherently challenging to control due to its incoherent nature. Recent advances have shown that patterned surfaces can transform thermal emission into partially coherent beams with tailored directionality and frequency selectivity. Here we experimentally demonstrate polarization-selective, unidirectional and narrowband thermal emission using single-layer metasurfaces. By implementing polarization gradients across the surface, we unveil a generalization of the photonic Rashba effect from circular polarizations to any pair of orthogonal polarizations and apply it to thermal emission. Leveraging pointwise specification of arbitrary elliptical polarization, we implement a thermal geometric phase and leverage it to prove previous theoretical predictions that asymmetric chiral emission is possible without violating reciprocity. This general platform can be extended to other frequency regimes in efforts to compactify metasurface optics technologies without the need for external coherent sources."

Metasurface makes thermal sources emit laser-like light – Physics World

Researchers Demonstrate Metasurfaces That Control Thermal Radiation in Unprecedented Ways (original news release) "The advance shows promise for creating compact, inexpensive, and portable light sources, which are crucial for space-based applications, biological and geological field research, and military operations."

Local control of polarization and geometric phase in thermal metasurfaces (no public access, but article above contains link to PDF)

Thermal emission control: A thermal metasurface is made of a single layer of nanostructured silicon (gray) on top of glass (blue) and a metal mirror. The nanostructured surface is tailored so that it thermally emits circularly polarized light in the desired direction.

World's fastest microscope freezes time at 1 attosecond

Amazing stuff!

"... previous efforts to capture events on that kind of timescale have gotten it down as far as 43 attoseconds, which the researchers at the time called “the shortest controlled event ever created by humankind.” And now, the U[niversity] of A[rizona] team has gone even shorter, freezing time at just one attosecond. ...
For the new study, the researchers developed what they call an “attomicroscope.” First, a pulse of ultraviolet light is fired off into a photocathode, which releases ultra-fast electrons inside the attomicroscope. Then, a laser pulse is split into two beams, which are both sent into the electrons moving through the microscope. One of those beams is polarized, and they arrive at slightly different times, generating a “gated” electron pulse that can image a sample – in this case, graphene. ..."

"Imagine owning a camera so powerful it can take freeze-frame photographs of a moving electron – an object traveling so fast it could circle the Earth many times in a second. Researchers at the University of Arizona have developed the world's fastest electron microscope that can do just that. ..."

From the abstract:

"Advances in attosecond spectroscopy have enabled tracing and controlling the electron motion dynamics in matter, although they have yielded insufficient information about the electron dynamic in the space domain. Hence, ultrafast electron and x-ray imaging tools have been developed to image the ultrafast dynamics of matter in real time and space. The cutting-edge temporal resolution of these imaging tools is on the order of a few tens to a hundred femtoseconds, limiting imaging to the atomic dynamics and leaving electron motion imaging out of reach. Here, we obtained the attosecond temporal resolution in the transmission electron microscope, which we coined “attomicroscopy.” We demonstrated this resolution by the attosecond diffraction measurements of the field-driven electron dynamics in graphene. This attosecond imaging tool would provide more insights into electron motion and directly connect it to the structural dynamics of matter in real-time and space domains, opening the door for long-anticipated real-life attosecond science applications in quantum physics, chemistry, and biology."

World's fastest microscope freezes time at 1 quintillionth of a second

Freeze-frame: U of A researchers develop microscope that can see electrons in motion (original news release)

Attosecond electron microscopy and diffraction (open access)

Fig. 1. Attosecond electron microscope setup.

Blink to Generate Power For These Smart Contact Lenses

Good news! Sounds intriguing! I am already rubbing my eyes already in anticipation of smart contact lenses! 😊

More power to and smarts for the eyes!

"The potential use cases for smart contacts are compelling and varied. Pop a lens on your eye and monitor health metrics like glucose levels; receive targeted drug delivery for ocular diseases; experience augmented reality and read news updates with displays of information literally in your face. ...

The harvesting occurs literally in the blink of an eye: When the eye is completely open, the harvester is off. Then when the eye starts to blink, the tear electrolytes meet the magnesium anode, causing an oxidation reaction and the generation of electrons. Finally the tear electrolytes come into contact with both an anode and the platinum cathode, creating more energy through further oxidation on the surface of the anode and oxygen reduction on the surface of the cathode. The electrodes are kept from fouling by the motion of the eyelid and continual refreshing of the tears. ...
Glaucoma is known as the silent thief of sight ..."

From the abstract:

"On-the-eye microsystems such as smart contacts for vision correction, health monitoring, drug delivery, and displaying information represent a new emerging class of low-profile (≤ 1 mm) wireless microsystems that conform to the curvature of the eyeball surface. The implementation of suitable low-profile power sources for eye-based microsystems on curved substrates is a major technical challenge addressed in this paper. The fabrication and characterization of a hybrid energy generation unit composed of a flexible silicon solar cell and eye-blinking activated Mg–O2 metal–air harvester capable of sustainably supplying electrical power to smart ocular devices are reported. The encapsulated photovoltaic device provides a DC output with a power density of 42.4 µW cm−2 and 2.5 mW cm−2 under indoor and outdoor lighting conditions, respectively. The eye-blinking activated Mg–air harvester delivers pulsed power output with a maximum power density of 1.3 mW cm−2. A power management circuit with an integrated 11 mF supercapacitor is used to convert the harvesters’ pulsed voltages to DC, boost up the voltages, and continuously deliver ≈150 µW at a stable 3.3 V DC output. Uniquely, in contrast to wireless power transfer, the power pack continuously generates electric power and does not require any type of external accessories for operation."

Blink to Generate Power For These Smart Contact Lenses - IEEE Spectrum A dual-mode power pack harvests energy from light and from tears

Power Scavenging Microsystem for Smart Contact Lenses (open access)

Fig. 1 Optoelectronic properties of the flexible silicon solar cells under indoor and outdoor lighting conditions; a) one individual cell, b) series connections between ten cells, and c) flexible silicon solar cell encapsulated in a PDMS contact

Novel optical metamaterial may make true one-way glass a reality

Is this not something we have been waiting for for centuries? 😊

"After decades of physics-based theorizing, researchers have succeeded in creating a novel optical metamaterial using conventional materials. Its enhanced electromagnetic effect may make true one-way glass a reality and solar panels more efficient. ...

In optical metamaterials, however, atoms are replaced by meta-atoms that can be structurally engineered to possess properties rarely seen in nature, enabling a design that produces unique electromagnetic responses and allows the precise manipulation of light at the nanoscale.

The ability to control and manipulate light at the nanoscale opens up many applications for metamaterials across various fields. Now, researchers ... have created a new optical metamaterial that may make true one-way glass a reality. ..."

"The new metamaterial takes advantage of the nonreciprocal magnetoelectric (NME) effect. The NME effect implies a link between specific properties of the material (its magnetization and polarization) and the different field components of light or other electromagnetic waves. The NME effect is negligible in natural materials, but scientists have been trying to enhance it using metamaterials and metasurfaces because of the technological potential this would unlock. 

‘So far, the NME effect has not led to realistic industrial applications. Most of the proposed approaches would only work for microwaves and not visible light, and they also couldn’t be fabricated with available technology,’ ... The team designed an optical NME metamaterial that can be created with existing technology, using conventional materials and nanofabrication techniques. 

The new material opens up applications that would otherwise need a strong external magnetic field to work – for example, creating truly one-way glass. Glass that’s currently sold as ‘one-way’ is just semi-transparent, letting light through in both directions.  ..."

From the abstract:

"The nonreciprocal magnetoelectric effect, also known as the Tellegen effect, promises a number of groundbreaking phenomena connected to fundamental (e.g., electrodynamics of axion and relativistic matter) and applied physics (e.g., magnetless isolators). We propose a three-dimensional metamaterial with an isotropic and resonant Tellegen response in the visible frequency range. The metamaterial is formed by randomly oriented bi-material nanocylinders in a host medium. Each nanocylinder consists of a ferromagnet in a single-domain magnetic state and a high-permittivity dielectric operating near the magnetic Mie-type resonance. The proposed metamaterial requires no external magnetic bias and operates on the spontaneous magnetization of the nanocylinders. By leveraging the emerging magnetic Weyl semimetals, we further show how a giant bulk effective magnetoelectric effect can be achieved in a proposed metamaterial, exceeding that of natural materials by almost four orders of magnitude."

Novel optical metamaterial may make true one-way glass a reality

A new optical metamaterial makes true one-way glass possible (Aalto University) Researchers have discovered how to make a new optical metamaterial that would underpin a variety of new technologies.

Optical Tellegen metamaterial with spontaneous magnetization (open access)

Fig. 2: Cobalt-based optical Tellegen meta-atom and isotropic Tellegen metamaterial with its effective material parameters.

Microscopy with Virtual Superlensing Made a Reality

Amazing stuff! Could take microscopy to a whole new level!

"... There are, however, physical limits to how closely we can examine an object using traditional optical methods. This is known as the ‘diffraction limit’ and is determined by the fact that light manifests as a wave. It means a focused image can never be smaller than half the wavelength of light used to observe an object.

Attempts to break this limit with “super lenses” have all hit the hurdle of extreme visual losses, making the lenses opaque. Now physicists at the University of Sydney have shown a new pathway to achieve superlensing with minimal losses, breaking through the diffraction limit by a factor of nearly four times. The key to their success was to remove the super lens altogether. ..."

"Absract

Imaging with resolutions much below the wavelength λ – now common in the visible spectrum – remains challenging at lower frequencies, where exponentially decaying evanescent waves are generally measured using a tip or antenna close to an object. Such approaches are often problematic because probes can perturb the near-field itself. Here we show that information encoded in evanescent waves can be probed further than previously thought, by reconstructing truthful images of the near-field through selective amplification of evanescent waves, akin to a virtual superlens that images the near field without perturbing it. We quantify trade-offs between noise and measurement distance, experimentally demonstrating reconstruction of complex images with subwavelength features down to a resolution of λ/7 and amplitude signal-to-noise ratios < 25dB between 0.18–1.5 THz. Our procedure can be implemented with any near-field probe, greatly relaxes experimental requirements for subwavelength imaging at sub-optical frequencies and opens the door to non-invasive near-field scanning."

Virtual Superlensing Made a Reality - IEEE Spectrum Researchers take a microstep backward to advance imaging techniques

Superlensing without a superlens: microscopes boosted beyond limits New technique could be used in medical imaging and advanced manufacturing

Subwavelength terahertz imaging via virtual superlensing in the radiating near field (open access)

Fig. 1: Concept schematic of virtual superlens

Superlensing without a super lens: Physicists boost microscopes beyond limits

Good news!

"... Now physicists at the University of Sydney have shown a new pathway to achieve superlensing with minimal losses, breaking through the diffraction limit by a factor of nearly four times. The key to their success was to remove the super lens altogether. ..."

"... “To do this, we placed our light probe far away from the object and collected both high- and low-resolution information. By measuring further away, the probe doesn’t interfere with the high-resolution data, a feature of previous methods.” ... “We overcome this by performing the superlens operation as a post-processing step on a computer, after the measurement itself. This produces a ‘truthful’ image of the object through the selective amplification of evanescent, or vanishing, light waves. ..."

From the abstract:

"Imaging with resolutions much below the wavelength λ – now common in the visible spectrum – remains challenging at lower frequencies, where exponentially decaying evanescent waves are generally measured using a tip or antenna close to an object. Such approaches are often problematic because probes can perturb the near-field itself. Here we show that information encoded in evanescent waves can be probed further than previously thought, by reconstructing truthful images of the near-field through selective amplification of evanescent waves, akin to a virtual superlens that images the near field without perturbing it. We quantify trade-offs between noise and measurement distance, experimentally demonstrating reconstruction of complex images with subwavelength features down to a resolution of λ/7 and amplitude signal-to-noise ratios < 25dB between 0.18–1.5 THz. Our procedure can be implemented with any near-field probe, greatly relaxes experimental requirements for subwavelength imaging at sub-optical frequencies and opens the door to non-invasive near-field scanning."

Superlensing without a super lens: Physicists boost microscopes beyond limits (secondary news source)

Superlensing without a superlens: microscopes boosted beyond limits (primary news source) New technique could be used in medical imaging and advanced manufacturing

Subwavelength terahertz imaging via virtual superlensing in the radiating near field (open access)

Fig. 1: Concept schematic of virtual superlens.

Optical microscopy with Ångström resolution

Good news! This could be a breakthrough! One Angstrom = 0.1 nm.

From the abstract:

"Fluorescence microscopy, with its molecular specificity, is one of the major characterization methods used in the life sciences to understand complex biological systems. Super-resolution approaches can achieve resolution in cells in the range of 15 to 20 nm, but interactions between individual biomolecules occur at length scales below 10 nm and characterization of intramolecular structure requires Ångström resolution. State-of-the-art super-resolution implementations have demonstrated spatial resolutions down to 5 nm and localization precisions of 1 nm under certain in vitro conditions. However, such resolutions do not directly translate to experiments in cells, and Ångström resolution has not been demonstrated to date. Here we introdue a DNA-barcoding method, resolution enhancement by sequential imaging (RESI), that improves the resolution of fluorescence microscopy down to the Ångström scale using off-the-shelf fluorescence microscopy hardware and reagents. By sequentially imaging sparse target subsets at moderate spatial resolutions of >15 nm, we demonstrate that single-protein resolution can be achieved for biomolecules in whole intact cells. Furthermore, we experimentally resolve the DNA backbone distance of single bases in DNA origami with Ångström resolution. We use our method in a proof-of-principle demonstration to map the molecular arrangement of the immunotherapy target CD20 in situ in untreated and drug-treated cells, which opens possibilities for assessing the molecular mechanisms of targeted immunotherapy. These observations demonstrate that, by enabling intramolecular imaging under ambient conditions in whole intact cells, RESI closes the gap between super-resolution microscopy and structural biology studies and thus delivers information key to understanding complex biological systems."

Ångström-resolution fluorescence microscopy | Nature (open access)

Fig. 1: RESI concept.

Cheap light microscope delivers super-resolution images

Amazing stuff! It appears we live in the exciting time of developing new and better microscopes. I just blogged here two days ago about another new microscope technology!

Wow, what opportunities will these latest two improvements to microscopy offer! This is very exciting!

 

"... The technique — which has recorded jaw-dropping images of individual proteins and never-before-seen structures in cells — offers a level of detail that eclipses even that of multi-million-dollar ‘super-resolution’ microscopes. ...
technique, dubbed ONE microscopy ...
technique ... melds the two approaches to achieve resolutions below 1 nm. That is sharp enough to reveal the shape of individual proteins, which are typically imaged in finer detail using much more expensive structural-biology methods such as cryo-electron microscopy (cryo-EM) or X-ray crystallography. ...
ONE (short for one-step nanoscale-expansion) microscopy uses heat or enzymes to also break the proteins apart, so that individual fragments are stretched in different directions during expansion. ..."

From the abstract:

"Fluorescence imaging is one of the most versatile and widely-used tools in biology. Although techniques to overcome the diffraction barrier were introduced more than two decades ago, and the nominal attainable resolution kept improving, , fluorescence microscopy still fails to image the morphology of single proteins or small molecular complexes, either purified or in a cellular context. Here we report a solution to this problem, in the form of one-step nanoscale expansion (ONE) microscopy. We combined the 10-fold axial expansion of the specimen (1000-fold by volume) with a fluorescence fluctuation analysis to enable the description of cultured cells, tissues, viral particles, molecular complexes and single proteins. At the cellular level, using immunostaining, our technology revealed detailed nanoscale arrangements of synaptic proteins, including a quasi-regular organisation of PSD95 clusters. At the single molecule level, upon main chain fluorescent labelling, we could visualise the shape of individual membrane and soluble proteins. Moreover, conformational changes undergone by the ∼17 kDa protein calmodulin upon Ca2+ binding were readily observable. We also imaged and classified molecular aggregates in cerebrospinal fluid samples from Parkinson’s Disease (PD) patients, which represents a promising new development towards improved PD diagnosis. ONE microscopy is compatible with conventional microscopes and can be performed with the software we provide here as a free, open-source package. This technology bridges the gap between high-resolution structural biology techniques and light microscopy, and provides a new avenue for discoveries in biology and medicine."

‘Democracy in microscopy’: cheap light microscope delivers super-resolution images

Visualizing proteins by expansion microscopy (open access)

This conventional confocal microscope can achieve nanoscale resolutions using the ONE-microscopy technique

Figure 2. ONE analysis of single molecules

Invention of a new kind of microscope inspired by a particular telescope and the scallop's eye

Amazing stuff! What will we be able to discover with this new microscope?

"... the scallop’s eye design resembled a kind of telescope invented nearly 100 years ago called the Schmidt telescope. The Kepler Space Telescope, which orbits Earth, uses a similar curved mirror design to magnify far-away light from exoplanets. ... that by shrinking the mirror, using lasers for light, and filling the space between the mirror and the detector with liquid to minimize light scattering, the design could be adapted to fit inside a microscope. ...
built a prototype based on those specs. Light enters from the top, passes through a curved plate that corrects for the mirror’s curvature, then bounces off a mirror to hit a sample and magnify it. The curved mirror can magnify the image much like a lens, ... It allows researchers to look at samples suspended in any kind of liquid, simplifying the process. .. the design could be particularly useful for researchers who study organs or even entire organisms, such as mice or embryos, that have been made completely transparent by artificially removing their pigment. ..."

From the abstract:

"Imaging large, cleared samples requires microscope objectives that combine a large field of view (FOV) with a long working distance (WD) and a high numerical aperture (NA). Ideally, such objectives should be compatible with a wide range of immersion media, which is challenging to achieve with conventional lens-based objective designs. Here we introduce the multi-immersion ‘Schmidt objective’ consisting of a spherical mirror and an aspherical correction plate as a solution to this problem. We demonstrate that a multi-photon variant of the Schmidt objective is compatible with all homogeneous immersion media and achieves an NA of 1.08 at a refractive index of 1.56, 1.1-mm FOV and 11-mm WD. We highlight its versatility by imaging cleared samples in various media ranging from air and water to benzyl alcohol/benzyl benzoate, dibenzyl ether and ethyl cinnamate and by imaging of neuronal activity in larval zebrafish in vivo. In principle, the concept can be extended to any imaging modality, including wide-field, confocal and light-sheet microscopy."

Inspired by the sea and the sky, a biologist invents a new kind of microscope | Science | AAAS The device can achieve clear images using samples suspended in any kind of liquid

Reflective multi-immersion microscope objectives inspired by the Schmidt telescope (open access)

Fig. 1: Concept of the multi-immersion Schmidt objective

Photoacoustic microscopy: Seeing More with a Needle-Shaped Laser

Good news! This seems to be a considerable improvement!

"... However, one limitation of high-resolution (i.e., optical-resolution) PAM has been its narrow depth of field, meaning that it can only focus on a thin layer (approximately 30 micrometers, or about the length of one skin cell, with one to two micrometers of resolution) of tissue at a time. To see something above or below the plane that the device is viewing, it needs to refocus above or below that plane. ...
developed a new variant of PAM called needle-shaped beam photoacoustic microscopy, or NB-PAM, which that has a depth of field nearly 14 times greater than what was achievable before. This means NB-PAM can create 3-D imagery of samples without refocusing and better image samples with uneven surfaces. ..."

From the abstract:

"Optical-resolution photoacoustic microscopy can visualize wavelength-dependent optical absorption at the cellular level. However, this technique suffers from a limited depth of field due to the tight focus of the optical excitation beam, making it challenging to acquire high-resolution images of samples with uneven surfaces or high-quality volumetric images without z scanning. To overcome this limitation, we propose needle-shaped beam photoacoustic microscopy, which can extend the depth of field to around a 28-fold Rayleigh length via customized diffractive optical elements. These diffractive optical elements generate a needle-shaped beam with a well-maintained beam diameter, a uniform axial intensity distribution and negligible sidelobes. The advantage of using needle-shaped beam photoacoustic microscopy is demonstrated via both histology-like imaging of fresh slide-free organs using a 266 nm laser and in vivo mouse-brain vasculature imaging using a 532 nm laser. This approach provides new perspectives for slide-free intraoperative pathological imaging and in vivo organ-level imaging."

Seeing More with a Needle-Shaped Laser | www.caltech.edu Photoacoustic microscopy (PAM) is a relatively new imaging technique that uses laser light to induce ultrasonic vibrations in tissue. These ultrasonic vibrations, along with a computer that processes them, can then be used to create an image of the structures of the tissue in much the same way ultrasound imaging works.

Optical-resolution photoacoustic microscopy with a needle-shaped beam (no public access)

Traditional photoacoustic microscopy (PAM) (left) compared to needle-shaped photoacoustic microscopy (NB-PAM) (right). In traditional PAM, only objects near the focal point of the laser are imaged sharply. In NB-PAM, the longer, narrower beam allows objects over a greater range of depth to be clearly imaged.

New Optical Switch Could Lead to Ultrafast All-Optical Signal Processing

Good news! Doing business, education, and recreation at the speed of light!

"... Two things made the breakthrough possible: the material ... and the way in which they used it. First, they chose a crystalline material known as lithium niobate, a combination of niobium, lithium, and oxygen that does not occur in nature but has, over the past 50 years, proven essential to the field of optics. The material is inherently nonlinear: ...

more recently, advances in nanofabrication techniques have enabled ... to create lithium niobate-based integrated photonic devices that allow for the confinement of light in a tiny space. The smaller the space, the greater the intensity of light with the same amount of power. ...

confined the light temporally. Essentially, they decreased the duration of light pulses, and used a specific design that would keep the pulses short as they propagate through the device, which resulted in each pulse having higher peak power.

The combined effect of these two tactics—the spatiotemporal confinement of light—is to substantially enhance the strength of nonlinearity for a given pulse energy ...

The net result is the creation of a nonlinear splitter in which the light pulses are routed to two different outputs based on their energies, which enables switching to occur in less than 50 femtoseconds ... By comparison, state-of-the-art electronic switches take tens of picoseconds ..."

From the abstract:

"Optical nonlinear functions are crucial for various applications in integrated photonics, including all-optical information processing, photonic neural networks and on-chip ultrafast light sources. ... Here we effectively utilize the strong and instantaneous quadratic nonlinearity of lithium niobate nanowaveguides for the realization of cavity-free all-optical switching. By simultaneous engineering of the dispersion and quasi-phase matching, we design and demonstrate a nonlinear splitter that can achieve ultralow switching energies down to 80 fJ, featuring a fastest switching time of ~46 fs and a lowest energy–time product of 3.7 × 10−27 J s in integrated photonics. Our results can enable on-chip ultrafast and energy-efficient all-optical information processing, computing systems and light sources."

New Optical Switch Could Lead to Ultrafast All-Optical Signal Processing | www.caltech.edu Engineers at Caltech have developed a switch—one of the most fundamental components of computing—using optical, rather than electronic, components. The development could aid efforts to achieve ultrafast all-optical signal processing and computing.

Femtojoule femtosecond all-optical switching in lithium niobate nanophotonics (no public access)

This camera lens can focus up close and far away at the same time

Amazing stuff! This is a very new type of photography technology

"Roughly 400 million years before the founding father invented bifocals, the now extinct trilobite Dalmanitina socialis already had a superior version ... Not only could the sea critter see things both near and far, it could also see both distances in focus at the same time — an ability that eludes most eyes and cameras.

Now, a new type of camera ... can simultaneously focus on two points anywhere between three centimeters and nearly two kilometers away ...
A high depth of field — the distance between the nearest and farthest points that a camera can bring into focus — is important for the relatively new technique of light-field photography, which uses many tiny lenses to produce 3-D photos. ..."

From the abstract:

"... Here, inspired by the optical structure of their eyes, we demonstrate a nanophotonic light-field camera incorporating a spin-multiplexed bifocal metalens array capable of capturing high-resolution light-field images over a record depth-of-field ranging from centimeter to kilometer scale, simultaneously enabling macro and telephoto modes in a snapshot imaging. By leveraging a multi-scale convolutional neural network-based reconstruction algorithm, optical aberrations induced by the metalens are eliminated, thereby significantly relaxing the design and performance limitations on metasurface optics. The elegant integration of nanophotonic technology with computational photography achieved here is expected to aid development of future high-performance imaging systems."

This camera lens can focus up close and far away at the same time | Science News The large depth of field helps recover distance information from a single image

Trilobite-inspired neural nanophotonic light-field camera with extreme depth-of-field (open access)

Lens fabricated in space for the first time using innovative technology

Amazing stuff! When will the first telescope be built on the moon?

"A historic moment: a lens was fabricated in space for the first time earlier this week, using innovative technology developed at the Technion – Israel Institute of Technology. The fluidic shaping method, developed by Prof. Moran Bercovici’s research team, in collaboration with NASA, could revolutionize space optics by overcoming the current limitations due to the size of the launcher and enabling fabrication of giant lenses for space telescopes. ..."

Lens fabricated in space for the first time earlier this week, using innovative technology

Cheap multifocal eyeglasses in minutes, not days thanks to 3D printing

Good news! I am not sure, I can even handle a multifocal lens dividing the lens in up to three different regions (top, middle, and bottom).

"As we get older, most of us will need glasses – first reading glasses, then multifocals (or progressives), a market worth some $12 billion in the United States alone. The total value of the vision-care industry tops $100 billion globally. ...

There are different grades of glasses, but the best can easily run over $1,000 a pair. There are also visual distortions to get used to, sometimes necessitating a change in prescription as the optometrist tries to get it exactly right, and a waiting period as the glasses are pressed at a factory, often far away.

A new technology from Israeli startup Addon Optics brings the factory into the optician’s office.

The company has developed a device the size of a toaster oven or a small 3D printer that can create a multifocal lens in six minutes at a fraction of the former cost, replacing a large manufacturing plant. ..."

Cheap multifocal eyeglasses in minutes, not days - ISRAEL21c New Israeli technology brings 3D printing to spectacles, lowering cost, footprint and wait time.