Quality enhancement with simultaneous suppression in excess noise of longer-lived states in non-uniformly pumped optical microcavities

TL;DR

This paper investigates how to enhance the quality factor and suppress excess noise in longer-lived states within non-uniformly pumped optical microcavities by exploiting avoided resonance crossings and internal coupling.

Contribution

It introduces a method to simultaneously improve Q-factor and reduce excess noise in optical microcavities through controlled internal coupling and gain/loss profiles, expanding understanding of resonance state manipulation.

Findings

Achieved suppression of Petermann factor close to 1

Demonstrated order of magnitude increase in Q-factor

Identified conditions for unconventional cavity resonance states

Abstract

We study the formation of longer lived states via internal coupling near a special avoided resonance crossing between the interacting states in an open optical system. Away from PT symmetry limit, we discuss the unconventional cavity resonance states created by a spatially varying gain/loss profile. Near certain avoided-resonant crossings (ARC), the parity symmetries of the chosen coupled states dictate the destructive interference resulting high Q, while avoided crossing in the imaginary part of the poles embraces the longer lived state. Now, via S-matrix formalism, we have numerically demonstrated that with suitably chosen system openness and coupling strengths, the excess noise generation among the interacting non-orthogonal states (calculated as Petermann factor K) can be suppressed close to the ideal value 1 with simultaneous order of magnitude enhancement in Q-factor of the longer lived state.