Page 82 - Tunable Lasers Handbook

in Tunable Laser

Spectroscopy *

Charles Freed
Lincoln Laboratory and the Department
of Electrical Engineering and Computer Science
Massachusetts Institute of Technology
Lexington, Massachusetts

1. INTRODUCTION

CO, molecular-gas lasers were invented by C. K. N. Patel in 1964 [1,2],
about four years after the first practical demonstration of a laser by Maiman [3].
Patel’s search for more efficient lasers led him to the first experiments utilizing
vibrational-rotational transitions of gas molecules, starting with CO,. Indeed, it
would be difficult to overemphasize the significance of Patel’s many sided con-
tributions to laser physics in general and to the development of CO, lasers in
particular. Within about a year after the invention, Patel and his coworkers deter-
mined the most salient aspects of CO, laser physics and processes that opened
the floodgate toward the development of truly high efficiency, high-power laser
systems [4].
The history, astonishing versatility, and multiplicity of applications of the
CO, laser system are most appropriately summarized in Patel’s seminal paper
entitled “Carbon Dioxide Laser, Journey from Milliwatts to Megawatts,” which
marked the 25th anniversary of the discovery of laser action on the vibrational-
rotational transitions of a molecule [5]. By that time in 1989, Patel found more
than 10,000 papers on the science, technology, and applications of CO, or other
molecular vibrational-rotational transition lasers. in addition to several books on

“Dedicated to Ruth and Louis ID. Smullin.

Tunable Lasers Handbook
Copyright Q 1995 by Academic Press, Inc. All rights of reproduction in any form reserved. 63