Thermal Radiation Polarization Analysis of the Crystal Fiber Growth Zone: Determination of the Crystal Melt Refractive Index

The thermal radiation spectra in two polarizations of the sapphire crystal fiber molten zone in the process of Laser Heating Pedestal Growth were investigated. As a result, a new method for determining the laser crystal melt refractive index for the spectral range of melt semitransparency was presented. The available now data on refractive indexes of the laser crystals melts at high temperature (> 2300 K) are very restricted and contradictory [1].