High quality two-photon pumped whispering-gallery-mode lasing from ultrathin CdS microflakes

We report low threshold, room temperature two-photon pumped whispering-gallery-mode (WGM) lasing from CdS microflakes with thicknesses down to 58 nm on mica substrates grown by self-limited van der Waals epitaxy. The relationship between the lasing properties and microflake size, as well as the recombination origins, is explored towards chip-level microlasers.