Quantum walk comb in a fast gain laser

Jérôme Faist (ETH Zürich)

Nov 7, 2023
4:00 pm to 5:00 pm | Pierce Hall, 209

Synthetic lattices in photonics enable the exploration of light states in new dimensions, transcending phenomena common only to physical space. In a recent publication in Science, we propose and demonstrate a quantum walk comb in synthetic frequency space formed by externally modulating a ring-shaped semiconductor laser with ultrafast recovery times. The initially ballistic quantum walk does not dissipate into low supermode states of the synthetic lattice; instead, the state stabilizes in a broad frequency comb, unlocking the full potential of the synthetic frequency lattice. Our device produces a low-noise, nearly flat broadband comb (reaching 100 per centimeter bandwidth) and offers a promising platform to generate broadband, tunable, and stable frequency combs.

Speaker Bio

Jérôme Faist (Fellow, IEEE) was born in Switzerland. He received the Ph.D. degree in physics from the Swiss Institute of Technology, Lausanne, Switzerland, in 1989. After a postdoc in IBM Rüschlikon (89- 91), he joined F. Capasso's group in Bell Laboratories in 1991. From 1997 to 2007, he was professor in the physics institute of the University of Neuchâtel. In 2007, he became professor in the institute for quantum electronics of the ETH Zürich. His current research interests include the development of mid-infrared and terahertz quantum cascade lasers and frequency combs and the physics of ultrastrong light-matter coupling in metamaterial resonators. He was a recipient of numerous awards for his key contribution to the development of the quantum cascade laser, including the IEEE/LEOS William Streifer Award for Scientific Achievement and the National Swiss Latsis Prize in 2003.


Shima Rajabali