The high-power trapping lasers in optical tweezers generate damaging heat. Here, the authors demonstrate efficient laser cooling using an erbium-ytterbium co-doped nanoparticle, which cools targets from high temperatures to near room temperature while avoiding sub-zero cooling from ambient conditions, thus enabling safe trapping of biological specimens.
- Xiaojun Guo
- Yanzhen Xiao
- Zhenglong Zhang
