High average laser power is required for industrial applications such as laser cutting and welding. However, system
performance is often limited by the achievable beam quality and focal length stability, both of which are degraded by
absorption in the transmissive components of the system. We explore in detail the behavior of uncoated and AR-coated
surfaces of Suprasil 3001, Corning 7980, and Spectrosil 2000 fused silica with respect to both surface and bulk
absorption in order to separate substrate effects from coating effects. Ion-beam sputtered AR coatings are shown to
contribute < 0.3 ppm of absorption per coated surface regardless of substrate material, potentially allowing design
flexibility in the selection of substrate materials at the system level.
Precision Photonics Corporation (PPC) has developed high Laser Damage Threshold (LDT) coatings for the important
2-3μm spectral region. Accurate information for both LDT and absorption for such coatings is sparse and often
unreliable, especially when compared to the huge amount of information for these parameters in the 1μm spectral region.
The goal of this effort is to provide useful, accurate information for high power/energy coatings, given the limited LDT
and absorption testing capabilities for the 2-3μm region. In this paper, we present data for 2μm pulsed LDT, 2μm
absorption, 3μm pulsed LDT, and Continuous Wave (CW) LDT data.
Precision Photonics Corporation (PPC) has developed a method of applying Ion Beam Sputtered (IBS) MWIR antireflective
coatings to the interior of a tangent ogive dome. Although IBS has traditionally not been used in this
application, it is known that IBS provides the highest density coatings using very hard, durable materials. We achieve a
variable coating thickness profile by means of shadow masking coupled with sophisticated 3 dimensional mathematical
modeling, which optimizes the antireflection performance over a wide range of look angles for an infrared seeker inside
the dome. The coating design for this project survives temperatures up to 1000ºC.
CTI is developing a compact and efficient multispectral laser transmitter for surf zone and on-shore active imaging, under a Phase II SBIR contract with MARCORSYSCOM. The transmitter will be tested with government-furnished sensors, and is designed to search for mines and surface targets in shallow water, beach, and low vegetation areas. The system will produce range-resolved, multispectral images suitable for automatic-target-recognition (ATR) algorithm processing. CTI has performed LADAR modeling of the relevant scenario, using camera calibration data provided by NSWC. Low-risk laser components are utilized in a novel device geometry that permits the development of very high wall plug efficiency with minimal cooling requirements. Preliminary laboratory results with the transmitter subsystems are given.