Origins of pre-commercial laser Doppler

A patent for the LASER (Light Amplification by Stimulated Emission of Radiation) was first filed in 1959 by Gordon Gould, a graduate student at Columbia University but denied. A subsequent patent filed in 1960 though was awarded to Charles H. Townes and Arthur L. Schawlow and soon after, Theodore H. Maiman at the Hughes Research Laboratories went on to prove the concept and build the first working laser. Over the 3 decades that followed a bitter patent war erupted with Gould subsequently being awarded 48 patents for commercially valuable aspects of the laser. Over a greater period of time than «the thirty year patent war», lasers would develop to become a seamless part in modern life with gas and diode lasers found in countless processes and applications.

Medical applications of the laser are now numerous but the basic principles of measuring blood flow by coupling the coherent radiation produced by the «laser» and the effect described by Christian Johann «Doppler» 1803-1853) were first described by Curtis C. Johnson of the University of Utah, in U.S. Pat. No. 3,511,227 filed in 1967. Another important milestone was reached as the laser Doppler technique was applied to the micro-circulation for the first time and described in Nature by researcher Michael D. Stern of the NIH, USA. The publication «In Vivo Evaluation of Microcirculation by Coherent Light Scattering» appeared in 1975 and sparked much global interest and has since been cited well over 1000 times. Following this, G Allen-Holloway refined and published further creating the seed for the first commercial laser Doppler system.