Non-mechanical method for tuning liquid laser wavelengths involves electrically varying temperature of laser medium. Technique is used to investigate behavior of laser dyes, and may lead to broad, tunable, light source for spectroscopy measurements of long path absorption

Billman, K. W.

Burnham, D. C.

Schappert, G. T.

English

NASA Technical Reports Server

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December 1970	 Brief 70-10480 
NASA TECH BRIEF 
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 progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Thermal Tuning of Organic Dye Lasers 
2	 3	 4	 5	 6	 7 
IO x lIT (K1) 
Figure 1. Center Lasing Frequency as a Function of 
Temperature for Four Dye Concentrations 
A new, non-mechanical method for tuning liquid 
laser wavelengths replaces previous mechanical pro-
cedures such as varying the cavity Q or the nature 
or concentration of the lasing medium. The new
method electrically varies the temperature of the las-
ing medium. 
The wavelength spectrum of an organic-dye laser 
(3,3'-diethylthiatricarbocyanine at various concen-
trations in ethanol), contained in a liquid nitrogen 
cooled dewar and longitudinally pumped by a 
switched ruby laser, was measured as a function 
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ABSORPTION
7800	 8000	 8200 
0 
x(A)
Figure 2. Measured Absorption and Fluorescence Spec-

tra. The circles indicate lasing wavelengths at different

concentrations. Below two such points are shown typical

spectra recorded for a 6 x 106 solution and plotted
on an identical intensity scale for the temperatures 1720

and 308°K. 
of temperature between - 117° and 78°C (Fig. I). 
The results were in qualitative agreement with the 
model of a vibrationally broadened two-level system, 
each level being separately thermalized. The absorp-
(continued overleul) 
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This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately ownedrights. 
https://ntrs.nasa.gov/search.jsp?R=19700000463 2020-03-17T00:31:33+00:00Z
tion and fluorescence spectra appear in Figure 2. 
The conversion efficiency (the ratio of output power 
to pump power) of this dye laser can be in-
creased by lowering the temperature. For example, 
an increase by a factor of 3 can be produced by 
a temperature change of froni +200 to - 60°C. 
The method may be used for investigating the be-
havior of laser dyes, and may lead to a broad, 
tunable, light source for spectroscopic applications, es-
pecially for measurements of long-path absorption. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Headquarters 
National Aeronautics 
and Space Administration 
Washington, DC. 20546 
Reference: TSP70- 10480
Patent status: 
This invention is owned by NASA, and a patent 
application has been filed. Royalty-free, nonexclusive 
licenses for its commercial use will be granted by 
NASA. Inquiries concerning license rights should be 
made to: 
Patent Counsel 
Mail Code 200-11 A 
Ames Research Center 
Moffett Field, California 94035 
Source: G. T. Schappert, K. W. Billman,

and D. C. Burnham

Electronics Research Center

(ERC-I0187) 
Brief 70-10480
	 Category 02


Thermal tuning of organic dye lasers

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