Nello and Colleagues Present Frequency-Resolved Squeezing Maps for Quantum Communication

Daniele Nello and colleagues report frequency-dependent quadrature squeezing in a quantum well laser, achieved using a fully quantum Langevin approach. The study reveals, for the first time, both frequency-dependent squeezing and complex squeezing within a semiconductor laser. A thorough analysis of the laser field’s squeezing map identifies optimal squeezing curves and examines the role of the linewidth enhancement factor. These results confirm semiconductor lasers as a key platform for generating non-classical light, potentially advancing applications in quantum communication and sensing. Previously unobserved, a hidden squeezing phenomenon was revealed within a semiconductor laser. Frequency-dependent squeezing extends the sub-shot-noise bandwidth beyond predictions based solely on amplitude squeezing.…