Apparatus in which laser wavelengths of two dyes are mixed in intracavity, nonlinear crystal provides intense source of coherent laser radiation which is tunable from visible through infrared wavelengths of electromagnetic spectrum

Billman, K. W.

English

NASA Technical Reports Server

May 1975	 . B75-10081 
NASA TECH BRIEF,.: 
Ames Research Center	
/ A 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Infrared Tunable Laser—A Concept 
. 
ft
The problem: 
To provide an intense source of coherent laser 
radiation which is tunable from the visible through 
the infrared wavelengths of the electromagnetic 
spectrum. 
The solution: 
An apparatus in which the laser wavelengths of 
two dyes are mixed in an intracavity, nonlinear crystal. 
How it's done: 
As shown in the diagram, the apparatus consists 
essentially of a dye cell containing a solution of at 
least two dyes (or a cell with separate compartments, 
each containing a dye in solution), a pair of diffrac-
tion gratings orthogonally disposed to a selectively 
reflecting dichroic mirror at one end of an optical 
cavity, an output mirror forming the other end of the 
optical cavity, and a nonlinear mixing crystal. 
When the dye cell is pumped by an intense light 
source, each dye lases over its characteristic radia-
tion band; the dichroic mirror is selected to reflect 
essentially all of a narrow band of wavelengths (y) 
produced by one of the lasing dyes and to transmit the 
narrow band (x) produced by the other lasing dye. By 
appropriate adjustment of the angular position of 
each of the gratings, small bands of radiation (about 
1 A wide, within the envelopes of the bands of wave-
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
length emitted by the lasing dyes) can be passed back 
through the dye cell and amplified. The amplified 
wavelengths are reflected back into the dye cell for 
further amplification because the mirror is selected 
so that it reflects lased light but transmits infrared 
radiation in the output wavelength region of interest. 
As the radiations in the sub-bands pass through the 
nonlinear mixing crystal, an additional wavelength 
develops which is a function of the two wavelengths 
selected by the diffraction gratings. 
By the proper choice of mirrors, dyes, and crystals, 
the output wavelength is tunable from approximately 
0.5 to 20 jkm. The apparatus is simpler and less ex-
pensive to construct than those based on Q-switched 
ruby lasers. It has particular usefulness in spectro-
scopic studies of atoms and molecules, and further 
application in the detection and monitoring of certain 
chemical species such as may be found in polluted 
atmospheres. 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B75-1 0081 
Patent status: 
This invention has been patented by NASA (U.S. 
Patent No. 3,753,148). Inquiries concerning nonex-
clusive or exclusive license for its commercial devel-
opment should be addressed to: 
NASA Patent Counsel 
Mail Code 200-11 A 
Ames Research Center 
Moffett Field, California 94035 
(continued overleaf) 
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19750000081 2020-03-19T20:03:54+00:00Z
Source: Kenneth W. Billman

Ames Research Center
(ARC-10463)
.. 
B75-10081	 Category 03


Infrared tunable laser: A concept

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