Chirped Lidar-radar for Medical Diagnostics

A new, emerging area of application involves the adaptation of microwave techniques to optical systems, such as hybrid lidar-radar for detection of underwater objects, aerial turbulence and tumors in human tissues. Microwaves and millimeter waves do not penetrate water or tissue, but light at specified wavelengths does and therefore lidar has been used for detection of objects submerged in water or embedded in tissue. However, these media intensely scatter light resulting in poor contrast and target identification. Light modulated at microwave frequencies, lidar-radar, has superior performance compared to lidar, as was demonstrated by Mullen et. al. [1,2]. In this approach the lidarradar echo is detected, the microwave envelope recovered and subjected to conventional, coherent radar signal processing. This paper concerns the development of a sophisticated lidar-radar technique, the chirped lidar-radar, with focus on medical applications, which by virtue of the short distances involved present the most stringent system requirements.