Application of solid immersion lens to high-spatial resolution photoluminescence imaging of GaAs quantum wells at low temperatures

A solid immersion lens (SIL) was applied to microscopic photoluminescence (PL) imaging at low temperatures. The spatial resolution corresponding to a numerical aperture of 1.0 was achieved and confirmed to be independent of temperature from 5 to 300 K. We performed PL imaging with the SIL for a GaAs quantum well and obtained stable PL images with high-spatial resolution at a wide temperature range from 5 to 200 K. From the temperature dependence of the PL images with high-spatial resolution, we can directly reveal the diffusion of photocarriers in the sample, which indicates the usefulness of the SIL technique.