Night-vision capabilities continue to be an important tactical tool for the warfighter. In fact, the proliferation of equipment over the past few decades has led to a significant amount of surplus equipment available at very low cost, which has eroded the tactical advantage for the United States that existed for some time. During the First Gulf War, the United States “owned the night,” with U.S. night-vision systems significantly outperforming Iraqi night-vision sensors.7 However, the current commercially available night-vision sensors are nearly equivalent to the best U.S. night-vision systems. Since the NRC’s 1998 Harnessing Light8 study, there have been substantial improvements in sensitivity, performance for uncooled systems, and expanded wavelength applicability, which have enabled practical thermal imaging systems for size, weight, and power (SWaP)-constrained platforms.
Laser Rangefinders, Designators, Jammers, and Communicators
The significant increase in laser diode efficiency coupled with the decrease in cost has enabled recent advances in laser designators. However, similar advances in night vision and imaging detector arrays have limited the use of laser designators and led to ground force casualties in recent engagements. Therefore, there is a greater push for SWaP improvements to enable designators on small unmanned platforms (e.g., micro-unmanned aerial vehicles [UAVs]), which will also carry over to active sensors and optical communication systems. Early laser designator systems used neodymium-doped yttrium aluminum garnet (Nd=YAG) lasers at 1 µm. However, improvements in laser materials and efficiency have enabled a wider range of wavelengths to be implemented.
A large investment in laser communications had been made prior to publication of the NRC’s 19989 report and has continued since that time. Optical communication in fibers has been steadily advancing in the past decade. The high carrier frequency of light, combined with the low attenuation in fiber, makes it attractive for telecommunications applications. For free-space applications, the short wavelength improves directivity by minimizing diffraction when compared to radio-frequency (RF) communications. This is one of the key motivators for moving to optical communications, which minimize the probability of interception, jamming, and detection while dramatically minimizing the power needed for a given communication bandwidth, since most of the energy can be focused on the receiver.
7 National Research Council. 2010. Seeing Photons: Progress and Limits of Visible and Infrared Sensor Arrays. Washington, D.C.: The National Academies Press.
8 National Research Council. 1998. Harnessing Light.
9 National Research Council. 1998. Harnessing Light.