(276i) Exploiting Anti-Stokes Photoluminescence of Quantum Dots to Achieve Optical Cooling

Optical cooling is a unique and promising cooling method capable of cooling to cryogenic temperatures in the absence of moving parts, noise, or vibration. Only a laser is used to pump in light; a semiconducting material upconverts this energy to reject higher energy photons producing a net cooling effect. Optical cooling is contrasted by mechanical systems, such as Stirling cryocoolers which can be loud, prone to vibration, and rapidly decrease in efficiency with thermal lift. Optical cooling may also be able to scale to the thermal load as the cooling power is linearly proportional to the laser power. And unlike thermoelectric Peltier coolers, optical coolers may be able to achieve temperatures of < 10 K

We will present our research toward developing and testing optical materials capable of cooling solely by anti-Stokes photoluminescence (PL). We developed optical cooling materials consisting of semiconductor nanoparticles, also known as quantum dots (QDs. The optical properties including absorbance spectrum, Stokes PL, anti-Stokes PL, and quantum yield were characterized and studied as a function of temperature for different populations of QDs. Testing results to demonstrate the first net cooling of a macroscopic sample using semiconducting materials will be presented, along with lessons learned.