Temperature gradient driven lasing and stimulated cooling

TL;DR

This paper explores a novel laser mechanism driven by a temperature gradient that not only produces laser emission but also enables stimulated cooling, potentially extending quantum cascade laser operation limits.

Contribution

It introduces a model of laser operation based on a spatial temperature gradient, revealing a new stimulated cooling mechanism and potential improvements for quantum cascade lasers.

Findings

Laser emission occurs with a sufficient temperature gradient and high resonator quality.

The mechanism enables concurrent heat flow amplification and laser operation.

Potential to extend quantum cascade laser temperature limits by replacing phonon emission with absorption.

Abstract

A laser can be understood as thermodynamic engine converting heat to a coherent single mode field close to Carnot efficiency. From this perspective spectral shaping of the excitation light generates a higher effective temperature on the pump than on the gain transition. Here, using a toy model of a quantum well structure with two suitably designed tunnel-coupled wells kept at different temperature, we study a laser operated on an actual spatial temperature gradient between pump and gain region. We predict gain and narrow band laser emission for a sufficient temperature gradient and resonator quality. Lasing appears concurrent with amplified heat flow and points to a new form of stimulated solid state cooling. Such a mechanism could raise the operating temperature limit of quantum cascade lasers by substituting phonon emission driven injection, which generates intrinsic heat, by an extended model with phonon absorption steps.