Experimental data pertaining to the intracavity propagation characteristics, the mode volume dissimilarity, and the fractional output coupling Characteristics associated with the oppositely traveling waves in CO 2 asymmetric unstable ring resonators are reported. Equivalence relations are derived, extending Siegman's unstable resonator analysis to encompass asymmetric traveling-wave geometries. Optical feedback techniques to suppress the oscillation associated with one of the traveling waves are demonstrated to be an effective means of achieving unidirectional ring laser operation.

Asymmetric unstable traveling-wave resonators

A review is presented of various recent investigations on the classical optical radiation laws in the light of the modern concepts of coherence and statistical optics. Temporal coherence of black-body radiation, spatial coherence of Lambertian and non-Lambertian sources, and the interaction of matter with radiation of any state of coherence are emphasized.

Coherence and the radiation laws

Radiometry and Coherence

This paper presents a complete analytical solution of the problem of far-field diffraction by apertures of a partially space-coherent wave-field. The effect of atmospheric turbulence on the far-field diffraction pattern has been studied as regards the intensity distribution, the factor of encircled energy distribution and the effective central illumination on the same. Numerical results are presented for a few representative aperatures. Indications are given regarding the convenient amenability of the approach to the problem of optimization.

Apodization of Telescopes Working in a Turbulent Medium

Partially coherent fresnel diffraction by a slit aperture. 1. Theoretical analysis

A formulation is developed for investigating the intensity distribution of Fresnel diffraction by a circular aperture illuminated with partially coherent light. The theory formulated is applied to obtain the intensity distribution along the normal axis to the aperture in the Fresnel diffraction field when the spatially mutual coherence function of the illumination over the aperture takes three different forms. It is shown that the Fresnel diffraction is largely influenced by the coherence condition across the diffracting aperture.

Fresnel Diffraction by a Circular Aperture Illuminated with Partially Coherent Light. I

The near- and far-field diffraction due to a circular aperture illuminated with partially coherent light produced by a turbulent medium has been theoretically studied. Formulations are developed for investigating the near- and far-field diffraction patterns. The phase structure function, which is generated by the turbulent medium and determines the partially coherent condition of a light beam passing through it, is assumed to take both the Gaussian form and the 5/3-power law. Numerical results concerning the far-field intensity distribution and the axial intensity distribution in the near-field region are presented in diagrams and discussed.

Issei Akamatsu

Papers

Fresnel Diffraction by a Circular Aperture Illuminated with Partially Coherent Light. I

Effect of a turbulent medium on the near- and far-field diffraction of a circular aperture