ANALYSIS AND EVALUATION OF SIMPLE ELECTROMAGNETIC MODELS FOR LASERS IN AXIAL MAGNETIC FIELDS AND PLANE DIFFRACTION GRATINGS.
TEXAS UNIV AUSTIN LABS FOR ELECTRONICS AND RELATED SCIENCE RESEARCH
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By using a vector Kirchoff integral and introducing suitable approximations for the electromagnetic fields on the surface of a plane diffraction grating, the fraction of the diffracted radiation appearing in each diffraction order is calculated here. The results are given as an explicit closed form function of the shape of the grooves on the grating surface and the wavelength of the incident radiation. On the basis of the analysis, it is shown that for a grating with triangular grooves which are wide and shallow compared to a wavelength of the incident radiation, the maximum amount of radiation is directed into a given diffraction order when the groove shape is such that the radiation is specularly reflected from one face. Finally, comparison with experimental data confirms the accuracy of the calculations in parameter ranges for which the simple model of the grating is expected to be valid. A simple electromagnetic model of a laser immersed in an axial magnetic field permits the polarization state of the emitted radiation to be described as a function of the single pass Faraday rotation angle and the anisotropy coefficient of the Brewster windows. It is shown that as the single pass Faraday rotation angle of the lasing medium is increased toward some critical value determined by the resonator anisotropies, the laser output fields are linearly polarized and the frequency remains constant. The output polarization angle increases to a maximum value psi sub o determined by the resonator anisotropies. Author
- Lasers and Masers