Degenerate optomechanical parametric oscillators: cooling in the vicinity of a critical point

TL;DR

This paper presents a new theoretical method to analyze degenerate optomechanical parametric oscillators near their critical point, revealing that significant mechanical cooling occurs through a cooling-by-heating mechanism, challenging previous semi-classical predictions.

Contribution

A novel theoretical approach capable of describing quantum regimes near the critical point in degenerate optomechanical systems, enabling analysis of cooling mechanisms in these complex regimes.

Findings

Mechanical cooling is induced by a cooling-by-heating process.

Cooling is not maximized at the critical point despite high photon numbers.

The new approach allows analysis of hybrid quantum systems near criticality.

Abstract

Degenerate optomechanical parametric oscillators are optical resonators in which a mechanical degree of freedom is coupled to a cavity mode that is nonlinearly amplified via parametric down-conversion of an external pumping laser. Below a critical pumping power the down-converted field is purely quantum-mechanical, making the theoretical description of such systems very challenging. Here we introduce a theoretical approach that is capable of describing this regime, even at the critical point itself. We find that the down-converted field can induce significant mechanical cooling and identify the process responsible of this as a cooling-by-heating mechanism. Moreover, we show that, contrary to naive expectations and semi-classical predictions, cooling is not optimal at the critical point, where the photon number is largest. Our approach opens the possibility for analyzing further hybrid dissipative quantum systems in the vicinity of critical points.