Solid-state Laser Cooling

TL;DR

This paper reviews the progress, key concepts, and experimental standards in solid-state laser cooling, emphasizing recent material developments and proposing reporting checklists to improve reproducibility.

Contribution

It consolidates advancements in solid-state laser cooling, introduces standardized reporting guidelines, and serves as a comprehensive tutorial for researchers in the field.

Findings

Progress in rare-earth-doped materials and semiconductors

Development of reporting checklists for reproducibility

Emerging applications in optical refrigeration

Abstract

Since the first proof-of-concept demonstrations of photoluminescence-based optical refrigeration, solid-state laser cooling has developed into a credible competitor to conventional cryogenic technologies. Solid-state laser cooling continues to advance as new materials push cooling limits. These developments have created a need to consolidate progress made to date as well as standardize critical experimental considerations needed for reliable and verifiable cooling measurements. This primer therefore outlines essential concepts and requirements, which underpin solid-state laser cooling. The primer summarizes key milestones achieved with cooling-grade, rare-earth-doped glasses and crystals as well as with semiconductors. It additionally highlights emerging applications of solid-state optical refrigeration. To strengthen the consistency and reproducibility of cooling results going forward, two reporting checklists are introduced. They cover materials, cooling metrics, and thermometry. This primer is intended to serve as both a tutorial and a practical reference for incoming and existing researchers involved in solid-state laser-cooling.