Dynamical properties of nanolasers based on few discrete emitters

TL;DR

This paper studies the dynamic behavior of nanolasers with few two-level emitters, deriving simplified rate equations that accurately predict their modulation response and revealing unique damping characteristics.

Contribution

It introduces a set of rate equations for nanolasers with few emitters, validated against full master equation solutions, and provides analytical expressions for their modulation response.

Findings

Nanolasers are typically over-damped with a dip in modulation bandwidth.

Rate equations accurately match full master equation solutions.

The unique damping is due to the incoherent pumping of two-level emitters.

Abstract

We investigate the dynamical properties of nanolasers comprising a few two-level emitters coupled to an optical cavity. A set of rate equations is derived, which agree very well with a solution of the full master equation model and makes it simple to investigate the properties of the system. Using a linearized version of these rate equations, we can analytically express the response of the nanolaser to a modulation of the pumping rate. These results are compared to the modulation response obtained directly from the master equation using a novel method. Using the rate equation method, we calculate the modulation bandwidth and show that, contrary to conventional semiconductor lasers, the nanolaser is typically over-damped and displays a dip in the modulation bandwidth as the two-level systems become inverted. Both these features can be traced back to the modeling of the emitters as two-level systems that are incoherently pumped.