A phase-amplitude-modulation technique. Applications to laser ranging and vibrodiagnostics

Lasers have found a lot of scientific and industrial applications. The unique properties of the laser radiation such as directionality, coherence and power open new ways for research in both theoretical and practical parts of modern science. Materials processing, medicine, optical data storage, semiconductor and microelectronics fabrication, spectroscopy, telecom, etc.---this is just a partial list of current applications of the laser. Also the invention of the laser gave a start to the development of brand new directions for research. Due to its properties, the laser has become a very useful tool for remote distance measurements, surface profiling and characterization of optically transparent materials. The first item of this list became a stand alone scientific application almost right after the invention of the laser and is known as "active laser ranging" nowadays. This work presents a novel phase-amplitude-modulation principle of active ranging and its application to laser ranging and vibrodiagnostics. An exact theoretical description of the proposed technique is given. Based on the developed theoretical model we present a laser-phase-amplitude-modulation vibrometer and a simple system for measurements of the length of optical fibers as practical applications of phase-amplitude-modulation technique. Both systems have been assembled and successfully tested. In the last chapter we present a wide-band phase-amplitude-modulation technique and its application to active ranging. Experimental results being obtained during experiments promise that both developed systems might be a serious alternative to all existing similar systems due to its low cost and simple assembly.