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):

Report Date:

1983-08-01

Pagination or Media Count:

125.0

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 Ananev 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.

Subject Categories:

  • Lasers and Masers
  • Statistics and Probability
  • Computer Programming and Software
  • Electromagnetic Pulses

Distribution Statement:

APPROVED FOR PUBLIC RELEASE