Stable, frequency upconverted lasing of semiconductor nanocrystal quantum dots was demonstrated in silica microbeads under two-photon pumping conditions. Upon infrared excitation, the stimulated emission of the nanocrystal-doped microbeads exhibits sharp peaks at λ∼610 nm with narrow line widths of 1 nm. The lasing action has been attributed to the biexciton gain coupled to the whispering gallery modes in spherical cavities, as confirmed by time-resolved photoluminescence spectra. The lasing lifetime characterized in term of pulse numbers (∼ 106 pulses) was two orders of magnitude longer than that of the dye salt-based two-photon lasers.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)