Effects Of Optical Aberrations Research Articles

Effect of optical aberrations on the output quality of a two-element laser

The effect of slight aberrations of an intracavity lens on the mode structure and the quality of the output from a two-element multimode laser is examined theoretically. The coefficients of the mode distortion due to optical aberrations of the intracavity elements are derived by perturbation theory. A general condition for the dynamic stability of the cavity of a two-element laser with respect to small fluctuations of the lens power of the active-element thermal lens is proposed. Recommendations are offered for optimizing the optical layout of the cavity of a two-element solid state laser. These recommendations are aimed at reducing the effect of aberrations on the quality of the transverse structure of the output. The procedure for designing an effective layout for a cavity of a two-element, solid-state industrial laser is illustrated.

Effect of optical aberrations on laser speckle

The output speckle statistics are affected by deterministic aberrations present in an imaging system when the speckle is only partially developed. The speckle-power spectral density and intensity contrast are shown to depend on these aberrations. The rough target surface is modeled as a perfectly transmitting (reflecting) surface with uniform phase distribution over (−α, α), where α ≤ π. The effects of the type and severity of the primary aberrations on the normalized power spectral density and intensity contrast are examined.

Collinear heterodyning in optical processors

The basic principles of several real-time optical processing schemes employing heterodyning are examined. In each case the method by which the correlation function is developed from the ultrasonic light modulator (ULM) is analyzed. It is shown that in some configurations it is possible to derive the heterodyne reference collinearly, thus increasing the mechanical stability and minimizing the effects of optical aberrations. Experimental results obtained with a correlator using a shear-wave ULM and collinear heterodyning confirm its stability and verify the fact that quality performance can be obtained with inexpensive optical components.

Informational Considerations in the Design of Astonomical Spectrographs

The problem of designing spectrographs so as to maximize their information rate on random low-contrast spectral distributions is considered. In Section 2 it is shown how spectrographs can be discussed within the general framework of Fourier optics. In Section 3 the effects of optical aberrations, of photographic spread and granularity, and of variation of slit width are briefly considered and the implications of the band-limitedness of optical images in the problem of allowing for instrumental bandwidth are pointed out. An approximate expression for the information rate is obtained in the special case of an aberration-free spectrograph.