Date of Award

Spring 2001

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Electrical & Computer Engineering

Program/Concentration

Electrical Engineering

Committee Director

Hani Elsayed-Ali

Committee Director

Russell J. De Young

Committee Member

Amin Dharamsi

Committee Member

Ravindra P. Joshi

Call Number for Print

Special Collections LD4331.E55 J66 2001

Abstract

The measurement of atmospheric ozone is important because in the troposphere it is a pollutant that is toxic to living systems, but in the stratosphere ozone protects life by shielding us from the sun's harmful UV-B radiation.

Laser remote sensing from aircraft using differential absorption lidar (DIAL) has become a very important technique for measuring atmospheric ozone at different altitudes and locations. Current aircraft-based DIAL systems use pulsed Nd:YAG pumped liquid dye lasers, which are then frequency doubled into the UV region, to probe both the stratosphere and troposphere for ozone.

This thesis describes a new potential DIAL laser transmitter using solid-state dye laser materials to make a simpler, more compact and lower mass laser system. Two solid-state dye laser materials were tested to evaluate their performance in a laser oscillator cavity end-pumped by a pulsed Nd: Y AG laser at 532 nm. Both dye laser materials are made from a solid-state polymer host polymethyl methacrylate (PMMA) where one of the materials was injected with a pyrromethene laser dye PM-580 and the other with PM-597. A narrowband laser oscillator cavity was constructed to produce visible wavelengths of 578 and 600 nm. The visible wavelengths produced by the PM- 597 dye laser material were frequency doubled into the UV region (289 or 300 nm) using a Beta-barium borate (BBO) crystal. The oscillator cavity produced a maximum energy of 11 mJ at a wavelength of 578 nm when pumped by the Nd: Y AG laser at a 532 nm energy of 100 mJ and pulse repetition rate of 10 Hz. A maximum output energy of 378 μJ was achieved in the UV region at a wavelength of 289 nm, but lasted only 2000 laser shots at a repetition rate of 10 Hz. A computer model was used to predict the conversion efficiency of the BBQ nonlinear crystal for comparison between theory and experimental results. The results are promising and show that a solid-state dye laser based ozone DIAL system is possible with improvements on the design of the laser transmitter.

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DOI

10.25777/2k5y-7x45

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