New Chalcogenide Glasses for Thermal Lensing-Free Windows

Multispectral imaging is gaining increasing interest in the defense world, due to its potential ability to reduce weight, size and power consumption of optical systems, while still maintaining the ability to capture images in multiple spectral bands. At the same time, the use of high-power, high-energy lasers is also increasing, most often in conjunction with an imaging system for targeting and data collection. The Overall Goal of this Phase I Research Proposal is to demonstrate the feasibility of producing an optical quality glass which can meet all of the demands outlined above for multispectral imaging applications. The specific requirements include the development of a chalcogenide glass window with a laser damage threshold of 1 MW/cm2 over the range of 1.030 to 1.070 µm, zero or near zero thermo-optic coefficient, especially at 1.064 µm, low absorption coefficient, 63.5% in the MWIR and LWIR regions, ideally out to 14 µm, and durability over a range of environmental conditions, including light exposure during storage, operating temperatures from -40°C to +71°C with humidity up to 95%, and storage and thermal shock from -51°C to +71°C.