Tunable optical second-order sideband effects in a parity-time symmetric optomechanical system

TL;DR

This paper theoretically explores how optical second-order sideband generation efficiency can be significantly enhanced and tuned in a parity-time symmetric optomechanical system near the exceptional point, with potential applications in optical communication.

Contribution

It introduces a method to enhance and control second-order sideband generation in PT-symmetric systems using atomic ensembles and pump power modulation.

Findings

Efficiency of OSSG increases sharply near the exceptional point.

OSSG efficiency is about 30% higher than first-order sideband.

Efficiency can be tuned via atom-cavity coupling and pump power.

Abstract

We theoretically investigate the optical second-order sideband generation (OSSG) in an optical parity-time (PT) symmetric system, which consists of a passive cavity trapping the atomic ensemble and an active cavity. It is found that near the exceptional point (EP), the efficiency of the OSSG increases sharply not only for the blue probe-pump detuning resonant case but also for the red one. Using experimentally achievable parameters, we study the effect of the atomic ensemble on the efficiency of the OSSG. The numerical results show that the efficiency of the OSSG is 30% higher than that of the first-order sideband, which is realized easily by simultaneously modulating the atom-cavity coupling strength and detuning. Moreover, the efficiency of the OSSG can also be tuned effectively by the pump power, and the efficiency is robust when the pump power is strong enough. This study may have some guidance for modulating the nonlinear optical properties and controlling light propagation, which may stimulate further applications in optical communications.