Laser refrigeration of gas filled hollow-core fibres

Abstract

We theoretically study prospects and limitations of a new route towards macroscopic scale laser refrigeration based on exciplex-mediated frequency up-conversion in gas filled hollow-core fibres. Using proven quantum optical rate equations we model the dynamics of a dopant-buffer gas mixture filling an optically pumped waveguide. In the particular example of alkali-noble gas mixtures, recent high pressure gas cell setup experiments have shown that efficient kinetic energy extraction cycles appear via the creation of transient exciplex excited electronic bound states. The cooling cycle consists of absorption of lower energy laser photons during collisions followed by blue-shifted spontaneous emission on the atomic line of the alkali atoms. For any arbitrary dopant-buffer gas mixture, we derive scaling laws for cooling power, cooling rates and temperature drops with varying input laser power, dopant and buffer gas concentration, fibre geometry and particularities of the exciplex ground and excited state potential landscapes.

Dynamic Brillouin cooling for continuous optomechanical systems

“…Among the laser cooling techniques that provide refrigeration for gases [44][45][46] and solids [47][48][49][50][51][52], Brillouin-based technologies provide cooling for groups of phonons in continuous optomechanical systems [53][54][55]. Brillouin-based optomechanical continuum cooling, i.e.…”