Study of Damage in Germanium Optical Window Irradiated by a Near-infrared Continuous Wave Laser

Lee, Kwang Hyun; Shin, Wan-Soon; Kang, Eung-Cheol

doi:2014.17.1.82

J. KIMS Technol > Volume 17(1); 2014 > Article

Journal of the Korea Institute of Military Science and Technology 2014;17(1):82-89.
DOI: https://doi.org/10.9766/KIMST.2014.17.1.082

Study of Damage in Germanium Optical Window Irradiated by a Near-infrared Continuous Wave Laser

Kwang Hyun Lee, Wan-Soon Shin, Eung-Cheol Kang

Advanced Technology Agile Development Center, Institute of Defense Advanced Technology Research, Agency for Defense Development

근적외선 연속발진 레이저 조사에 의한 게르마늄 광학창 손상 연구

이광현, 신완순, 강응철

국방과학연구소 국방고등기술원 첨단기술연구센터

Abstract

The damage in germanium (Ge) optical window irradiated by a near-infrared continuous wave (CW) laser was studied. Laser-induced heating and melting process were surveyed, and the specific laser power and the irradiance time to melt were estimated by numerical simulation. The experiments were also carried out to investigate the macro and micro structure change on Ge window. Results showed that the surface deformation was formed by melting and resolidification process, the damaged surface had a polycrystalline phase, and the transmittance as an optical performance factor in mid-infrared region was decreased. We confirmed that an abnormal polycrystalline phase and surface deformation effect such as hillock formation and roughness increase reduced the transmittance of Ge window and were the damage mechanism of CW laser induced damage on Ge window.

Key Words: Continuous Wave Laser, Ge Window, Laser Induced Damage