Accession Number : ADA136515

Title :   Transverse Mode Formation in Positive Branch Unstable Resonators.

Descriptive Note : Technical rept.,

Corporate Author : ARMY MISSILE COMMAND REDSTONE ARSENAL AL DIRECTED ENERGY DIRECTORATE

Personal Author(s) : Jones, R W

PDF Url : ADA136515

Report Date : Aug 1983

Pagination or Media Count : 125

Abstract : The dynamics of transverse mode formation in positive branch unstable resonators with moderate magnification (1.32 M 2.7) and typical Fresenel numbers (279 NT 10,800) used in high energy lasers has been investigated. The objective was to observe the far-field intensity distribution from the onset of pumping to the steady-state diffraction limited pattern. The research consisted of experimental and numerical analyses. The experimental measurements of mode formation time were performed using a pulsed CO2 laser and a pulsed XeF laser. Mode formation was deduced from observation of the far-field. The analytical effort consisted of a Fast Fourier Transform (FFT) wave optics computation which modeled the far-field pattern evolution. Results agree with the temporal mode formation geometrical theory of Anan'ev when laser saturation is achieved at the predicted mode formation time in a CO2 laser. Rapid saturation at one-third this time results in significant earlier mode formation compared to the geometrical theory for a XeF laser. (Author).

Descriptors :   *Laser cavities, *Cavity resonators, *Stability, *Transverse waves, *Electromagnetic wave propagation, *Microwave optics, *Pulsed lasers, High gain, Near field, Far field, Intensity, Patterns, Carbon dioxide lasers, Xenon lasers, Computer applications, Computer programs, Experimental data, Numerical analysis, Statistical analysis, Models, Fast fourier transforms, Fresnel integrals, Laser pumping, Kinetics, Laser beams, Focusing, Propagation, Wavefronts, High energy, Light pulses

Subject Categories : Lasers and Masers
      Statistics and Probability
      Computer Programming and Software
      Electromagnetic Pulses

Distribution Statement : APPROVED FOR PUBLIC RELEASE