# Laser cooling of molecules

## TL;DR

Recent advances have enabled laser cooling of molecules despite their complex energy structures, leading to ultracold temperatures and trapping, which opens new avenues in quantum science, chemistry, and fundamental physics.

## Contribution

This paper reviews recent progress in laser cooling of molecules, highlighting techniques to overcome their complex energy levels and discussing future applications.

## Key findings

- Molecules can be cooled to a few microkelvin.
- Molecules can be trapped for several seconds.
- Laser cooling techniques have been successfully extended to molecules.

## Abstract

Recently, laser cooling methods have been extended from atoms to molecules. The complex rotational and vibrational energy level structure of molecules makes laser cooling difficult, but these difficulties have been overcome and molecules have now been cooled to a few microkelvin and trapped for several seconds. This opens many possibilities for applications in quantum science and technology, controlled chemistry, and tests of fundamental physics. This article explains how molecules can be decelerated, cooled and trapped using laser light, reviews the progress made in recent years, and outlines some future applications.