Anti-Stokes photoluminescence and optical cooling of CdSeS/ZnS colloidal quantum dots embedded in dielectric waveguides

摘要

Anti-Stokes photoluminescence from colloidal CdSeS/ZnS quantum dots (QDs) is observed. The QDs were inserted intothe core of wider-bandgap SiO_2/Si_3N_4/SiO_2 structure by thin film deposition and confirmed as promising nanoemittersfor laser cooling due to efficient anti-Stokes emission. The nanoemitters were optically pumped by semiconductor laserscoupled to the waveguides using free-space optics. A direct evidence of local optical cooling in the waveguide structurehas been demonstrated with a luminescence thermometry based on the detection of photoluminescence signal phasechange versus power of the pumping laser, using a lock-in amplifier.