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Original experiments on measurements of the coherence length of diffusely scattered CW laser beams using GaAs adaptive photodetectors based on the photo-EMF effect are presented. Simplicity of the configuration, capability to detect aberrated speckle-like wavefronts with high signal-to-noise ratio, and potentially high speed of operation make this configuration potentially useful for Optical Coherence Tomography and Laser Ranging.

Summary form only given. We present the first results of experiments with GaAs adaptive photodetectors and superluminiscent diodes (SLD). These semiconductor light sources have very short coherence lengths (tens of microns) required for such important applications as high resolution laser ranging, profilometry, and medical optical coherence tomography.

Summary form only given. Earlier we have reported application of the photo-EMF based adaptive detectors for coherence measurements of the laser beams, including those reflected from rough surfaces. Later, application of this technique for laser profilometry of as-processed metal surfaces was experimentally demonstrated. Here we present for the first time, micron resolution monitoring of in-depth distribution of the reflectance i.e., another step to application of this technique to Optical Coherence Tomography.

A laser profilometer based on adaptive photo-EMF detector that can find application for testing optically rough surfaces is described. Depth resolution of the configuration is shown to depend on not only the coherence length of the wide-spectrum light source used, but also the interelectrode spacing of the detector and crossing angle of interfering beams. Experimental demonstration of the device having an approximately 10 mm resolution and using a GaAs photo-EMF detector and a superluminescent diode was performed in tests of multisurface reflecting object.

A method to obtain spiral fringes and embedded vortices is presented. Both beam Bessel obstruction and interference with a reference wave are involved. Corresponding phase reconstruction is achieved with single shot phase-shifting interferometry.