Quantum Langevin approach for superradiant nanolasers

TL;DR

This paper introduces a novel analytical method using quantum Langevin equations to study superradiant nanolasers, revealing new spectral features and emphasizing the role of population fluctuations in laser behavior.

Contribution

It presents a new analytical approach for solving quantum nonlinear Langevin equations applied to superradiant lasers, uncovering novel spectral phenomena and insights into laser linewidth narrowing.

Findings

Predicted new sideband peaks in superradiant laser spectra.

Identified nonlinear spectral structures at weak pump rates.

Revealed the significance of population fluctuations in laser linewidth.

Abstract

A new approach for analytically solving quantum nonlinear Langevin equations is proposed and applied to calculations of spectra of superradiant lasers where collective effects play an important role. We calculate lasing spectra for arbitrary pump rates and recover well-known results such as the pump dependence of the laser linewidth across the threshold region. We predict new sideband peaks in the spectrum of superradiant lasers with large relaxation oscillations as well as new nonlinear structures in the lasing spectra for weak pump rates. Our approach sheds new light on the importance of population fluctuations in the narrowing of the laser linewidth, in the structure of the lasing spectrum, and in the transition to coherent operation.