Computer controlled intracavity second harmonic generation in a CW Dye Ring Laser
Marshall, Charles McAlister
Tittel, Frank K.
Master of Science
The purpose of this research has been to develop a source of high power narrowline ultraviolet radiation suitable for spectroscopic applications. This was accomplished by using intracavity second harmonic generation in a computer controlled continuous wave dye ring laser. A DEC POP 11/3 minicomputer was used to control laser tuning elements and nonlinear crystal temperature to provide constant UV output powers of over 1 mW with a short term linewidth of + 5 MHz at the peak of the Rh6G gain curve. The computer system with a CAMAC interface provided control of laser calibration and scanning as well as data acquisition and storage over the wavelength range from 285 to 35 nm. The spectrometer development included the design-of an astigmatically compensated ring laser to provide optimal conversion of intracavity fundamental power to second harmonic UV output. Both Brewster cut and normal incidence crystals were analyzed to determine the most efficient insertion technique. The Brewster cut crystal was found to provide the highest output powers with the fewest complications. The system development also included techniques for long range temperature tuning of the nonlinear crystal to provide constant UV output over continuous frequency intervals of 32 GHz. The performance of the spectrometer was evaluated through studying the absorption spectra of SO around 3 nm. A simultaneous visible output at 6 nm was used to provide a reference spectra of the well documented fluorescence of I2.