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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.

The relative phase gate is a new two-qubit gate that has been recently defined. This gate introduces a phase on two qubits when the two basis states are on unequal states and it is a natural and logical extension of the one-qubit phase gate. When the phase introduced is π it produces the following evolution Urelative (α|0 1 + β|1 1 ) (γ|0 2 + δ|1 2 ) (α|0 1 β|1 1 ) (γ|0 2 δ|1 2 ). When the phase is arbitrary it produces an entangled state. The goal of this paper is to characterize the relative phase gate by studying the properties of the entangled state generated by its application on an unknown or arbitrary state. This is a new quantum entangled state which have special characteristics. We calculate its Concurrence and Geometric Measure of Entanglement (GME) and compare them to the respective entanglement measure of the states generated by the application of the control Z phase gate to the unknown state.

It is shown that, departing from Dirac's intensity - phase commutator, a Hermitian operator can be found, conjugate to the number operator, N. We also show that this operator is equivalent to that given by Turski.

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.

This paper explains and illustrates the application of the evolution operator method to solve problems in quantum mechanics. Currently, this method has been proposed as a useful way to overcome some misconceptions in quantum mechanics. To illustrate the method, we apply it to analyze and study the case of a quantum system inside an infinite square well potential (ISWP), and compare this result with that obtained using the traditional method. Also, we analyze the collapse and revival phenomenon in the ISWP. In this case, we argue that the usual approach to studying this effect requires one to extend the function's domain to infinity; however, there has not been any assurance that this extension preserves the self-adjointness of the Hamiltonian operator. The self-adjointness of the Hamiltonian operator is a vital requirement to guarantee the uniqueness of the Schrodinger equation's solution.

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.