SWIR laser gated-viewing at Fraunhofer IOSB

This paper reviews the work that has been done at Fraunhofer IOSB (and its predecessor institutes) in the past ten years in the area of laser gated-viewing (GV) in the short-wavelength infrared (SWIR) band. Experimental system demonstrators in various configurations have been built up in order to show the potential for different applications and to investigate specific topics. The wavelength of the pulsed illumination laser is around 1.57 mm and lies in the invisible, retina-safe region allowing much higher pulse energies than for wavelengths in the visible or near-infrared band concerning eye safety. All systems built up, consist of gated Intevac LIVAR® cameras based on EBCCD/EBCMOS detectors sensitive in the SWIR band. This review comprises military and civilian applications in maritime and land domain - in particular vision enhancement in bad visibility, long-range applications, silhouette imaging, 3-D imaging by sliding gates and slope method, bi-static GV imaging and looking through windows. In addition, theoretical studies that were conducted - for example estimating 3-D accuracy or modelling range performance - are presented. Finally, an outlook for future work in the area of SWIR laser GV at Fraunhofer IOSB is given.