Response to “Comment on ‘ZnGeP2 birefringence and its temperature dispersion using polarized interference’ ” [J. Appl. Phys. 87, 4638 (2000)

Abstract

In 1984 Andreev et al. [Sov. J. Quantum Electron. 14, 1021 (1984)] initiated a controversy by reporting that theory fails to predict the experimental phase matching angles for second harmonic generation of CO2 pump lasers or even that phase matching is possible at the longer wavelengths. As the phase matching angle under discussion is determined by the refractive indices, Andreev speculated that the index data of Boyd et al. [Appl. Phys. Lett. 18, 301 (1971)] were incorrect and that by assuming a larger birefringence, the discrepancy could be resolved. However, it was found that these index values were remarkably accurate. Bhar and Kumbhakar [J. Appl. Phys. 87, 4638 (2000)], speculate that the required birefringence is obtained as a result of a 180 °C rise in the crystal temperature due to absorption. In this reply, it is argued that their speculation is inconsistent with the results of numerous experiments and most importantly, that this large temperature rise occurs cannot be accepted as a fact without experimental verification.