Quantum Walk Comb in a Fast Gain Laser
arXiv:2309.00446 · doi:10.1126/science.adj3858
Abstract
Synthetic lattices in photonics enable the exploration of light states in new dimensions, transcending phenomena common only to physical space. We propose and demonstrate a Quantum Walk Laser in synthetic frequency space formed by externally modulating a ring-shaped semiconductor laser with ultrafast recovery times. In this device, the initially ballistic quantum walk does not dissipate into low supermode states of the synthetic lattice; instead, thanks to the fast-gain nonlinearity of our quantum cascade laser active material, the state stabilizes in a broad frequency comb, unlocking the full potential of the lattice. This device produces a low-noise, nearly-flat broadband comb (reaching 100 cm bandwidth), well predicted by our models. The proposed Quantum Walk Laser offers a promising platform to generate broadband, tunable and stable frequency combs.
This is the author's version of the work. The definitive version was published in Science on 2023/10/27, 10.1126/science.adj3858 (10 pages, 4 figures)