William Cho

Second Harmonic Generation Microscopy

We present a design of a second harmonic generation microscope to perform spectroscopy and imaging at low temperature. A vacuum chamber houses nano-positioners and the sample, and intense laser light is sent to the sample through a glass viewport in the chamber. The reflected light from the sample is then filtered for second harmonic generated light and passed into a detector. In addition, a novel thermal isolator is used to keep the sample cold. The thermal isolator utilizes atomic point contacts between hard ceramic spheres to insulate the sample. From a test with liquid nitrogen, the thermal isolator has a thermal conductance of 2.4 mW/K.