High-temperature Infrared Transmission of Free-standing Diamond Films

HEI Li-fu, YAN Xiong-bo, ZHU Rui-hua, CHEN Liang-xian, LIU Jin-long, WEI Jun-jun, LIAN Wei-yan, ZHANG Rong-shi, LI Cheng-ming
2017 Journal of Materials Engineering  
The combination of low absorption and extreme mechanical and thermal properties make diamond a compelling choice for some more extreme far infrared (8-12 μm) window applications. The optical properties of CVD diamond at elevated temperatures are critical to many of these extreme applications. The infrared transmission of free-standing diamond films prepared by DC arc plasma jet were studied at temperature varied conditions. The surface morphology, structure feature and infrared optical
more » ... ed optical properties of diamond films were tested by optical microscope, X-ray diffraction, laser Raman and Fourier-transform infrared spectroscopy. The results show that the average transmittance for 8-12μm is decreased from 65.95% at 27℃ to 52.5% at 500℃,and the transmittance drop is in three stages. Corresponding to the drop of transmittance with the temperature, diamond film absorption coefficient increases with the rise of temperature. The influence of the change of surface state of diamond films on the optical properties of diamond films is significantly greater than the influence on the internal structure.
doi:10.11868/j.issn.1001-4381.2016.000792 doaj:001e8dafaabe4ae9a0aa2c797701fce0 fatcat:4jljhm6wrfdmhd5lq7c5v2mlgu