We report on the realization of neodymium-doped silica microsphere laser, of diameters in the range 50-100 μm. Following very low threshold observed at room temperature (absorbed pump power of 200 nW), we present the new cryogenic setup operating at 2K. Very high quality factor Q > 3 × 108 has been preserved in a 50 μm diameter microsphere immersed in superfluid Helium. Preliminary results on lasing at this temperature have also been obtained as a first step towards a 'thresholdless' regime.
- Cavity quantum electrodynamics
- Monolithic microcavities
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics