Friday, November 17, 2023

Picosecond Lasers on nanometer size Chips

Amazing stuff! Pushing the limits of nature!

"... These ultrashort pulses are also extensively used for imaging applications because they can have extremely large peak intensities but low average power, so they avoid heating or even burning up samples such as biological tissues. ..."

From the editor's summary and abstract:
"Editor’s summary
Mode-locked lasers are an enabling technology in the ultrafast sciences, providing a platform to generate extremely short pulses of coherent light and precisely spaced frequency combs of light. These lasers are typically bulky, with components sitting on an optical bench. Guo et al. shrunk a mode-locked laser down to the size of an optical chip. Combing a III-V gain medium with a lithium-niobate phase modulator, they demonstrated the operation of a mode-locked laser with good performance metrics. The results show promise for developing photonic chip–based frequency combs for precision measurements and spectroscopy. ...
Abstract
Mode-locked lasers (MLLs) generate ultrashort pulses with peak powers substantially exceeding their average powers. However, integrated MLLs that drive ultrafast nanophotonic circuits have remained elusive because of their typically low peak powers, lack of controllability, and challenges when integrating with nanophotonic platforms. In this work, we demonstrate an electrically pumped actively MLL in nanophotonic lithium niobate based on its hybrid integration with a III-V semiconductor optical amplifier. Our MLL generates 
4.8-ps optical pulses around 1065 nm at a repetition rate of ∼10 GHz, with energies exceeding 2.6 pJ and peak powers beyond 0.5 W. The repetition rate and the carrier-envelope offset frequency of the output can be controlled in a wide range by using the driving frequency and the pump current, providing a route for fully stabilized on-chip frequency combs."

Ultrafast Lasers on Ultratiny Chips | www.caltech.edu Lasers have become relatively commonplace in everyday life, but they have many uses outside of providing light shows at raves and scanning barcodes on groceries. Lasers are also of great importance in telecommunications and computing as well as biology, chemistry, and physics research.

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