Effects of deposition temperature on resistant-boat evaporated MgF2 films

Single layers of MgF2 were deposited upon super polished fused-silica substrates by resistance boat evaporation at different temperatures from 200 ℃ to 350 ℃ by increasing step of 50 ℃. The transmittance and reflectance spectra were measured and the root-mean-square surface roughness was determined. The total optical loss and scattering loss were calculated. The laser-induced damage threshold(LIDT) was characterized at the wavelength of 355 nm for certain samples. It was found that the total optical loss and the root-mean-square surface roughness increased with the increasing of the deposition temperature. At the short wavelength period the increasing total optical loss at certain deposition temperature was mainly caused by absorption while scattering loss occupied a very low percentage