An adjustable mirror mount system for a mirror is disclosed comprising a mirror support having a planar surface thereon, a mirror frame containing a mirror and having a planar surface behind the mirror facing the planar surface of the mirror support and parallel to the reflecting surface of the mirror and mounted pivotally to the mirror support at a point central to the frame, a first adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along one axis lying in the plane of the planar surface of the mirror frame; and a second adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along a second axis lying in the plane of the planar surface of the mirror frame and perpendicular to the first axis.

Kinematic high bandwidth mirror mount

A low diffraction-feedback high-energy laser system includes an injection laser, and a master power amplifier (MOPA). The master oscillator power amplifier preferably includes a convex and a concave cavity reflector. A sensor mounted to the convex reflector is operative to provide a signal indication of cavity turbulence.

Limited diffraction feedback laser system having a cavity turbulence monitor

An accurate electro-optical method was developed to measure slitwidths in the 0.5 to 400 micron range. A prototype instrument was built that gave experimental evidence of accuracy, resolution and reproducibility of measured data. The present setup covers a width range between 40 and 260 microns. Throughout this range a better than 1 percent resolution was demonstrated. The Atlantic Research technique uses a laterally moving optical fringe pattern, that is generated by two laser beams, converging at a small angle. The two laser beams are identical in intensity, derived from the same laser by using a Bragg cell as a beamsplitter. One of the two laser beams is shifted in frequency by an amount determined by the ultrasonic frequency of the Bragg cell, which causes the fringes to move in a direction perpendicular to their plane. Since the fringe spacing in the interference zone is constant (determined by the laser wavelength and the converging angle of the two laser beams), it can be used as a "yardstick" to compare its length to dimensions such as width of a slit. When the fringe spacing equals the slitwidth, the RF component of the transmitted radiation becomes zero. Accurate positioning of the slit (to be measured) in the fringe field is not necessary; however, a good angular alignment with the fringes is desired to obtain good signal-to-noise ratios.© (1974) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Accurate Measurement Of Slitwidths In Microphoto Fabrication Based On Lateral Interferometry

With recent advances in miniature high performance tip and tilt mirror components (see details in another paper presented in this seminar), it is feasible to dynamically compensate for angular misalignment of intracavity optical components. The control system described in this paper seeks to maximize output power. The 2-axis active mirror mount is operated in a spiral scan mode searching for the optimum alignment in 2 dimensions. Data (frame) updating rates of 20 frames per second have been achieved by using a small 2" diameter beryllium mirror driven by a pair of "shaker motors." Extensions of this and similar approaches to different practical applications will be discussed together with preliminary experimental results.© (1978) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Intracavity Tip And Tilt Adaptive Control Experiments

While developing a fiber diameter measuring instrument that is based on lateral interferometry (LI), we became aware of another application which opens up exciting opportunities - the automatic-noncontact detection and monitoring of imperfections in high quality surfaces. Quality assurance for such surfaces has become a major problem in the semiconductor industry where such surfaces are regularly produced on silicon disks. Comparable, or higher surface quality requirements also exist in other branches of the laser optics industry. The proposed surface quality monitor utilizes a high precision optical interference pattern which is projected onto a target surface to determine the presence and size of imperfections. The measurement technique involves the use of a low power laser beam which is split into two beams of slightly different frequency us,ng an acoustic-optical (A-0) device. When the split beam is again merged, a small (in the order of lmm2), accurate optical interference pattern is produced on the test surface. This interference pattern consists of a large number of fringes that move rapidly in a direction perpendicular to the fringe planes. The AC component of the optical radiation, back scattered from the exposed (illuminated) portion of the test surface contains the information on the surface quality of that segment of the surface. By using conventional raster scan techniques, the whole test surface is scanned systematically. The paper describes analytical and experimental results together with a brief review of potential applications.© (1977) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Martin Tarabocchia

Papers

Intracavity Tip And Tilt Adaptive Control Experiments

Detection Of Microscopic Imperfections On High Quality Surfaces