Photochromic effect of oxygen-contained yttrium hydride
Oxygen-contained yttrium hydride is a photochromic material. Illuminated with 442 nm light, the color of the material will change from transparent to a darkened black-like color. The film will turn back to transparent after turning off the light. To understand the reversible color change, I study (1) the transmittance and reflectance change of the material at different illumination wavelength and power; (2) scattered Raman signal during illumination.