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[en] The temperature dependence of photoresponse of two high-temperature superconductors' junction has been investigated for the exciting radiation modulation frequency range from 2 to 2000 Hz. Together with the thermoelectricity we have registered the potential conditioned by the nonequilibrium processes due to photoexcitation. 12 refs
[en] Twyman-green interferometer has been stabilized to measure the length, surface profile, displacement, vibration, and etc. The interferometer is actively stabilized by using He-Ne laser with the wavelength of 633 nm. The interferometer was stabilized by using fringe locking method, which the reference mirror was pushed back to the original position of the fringe by applying the amplified error voltage when a fringe moves due to the harsh environment perturbations such as vibration, air turbulence, and etc.
[en] This paper presents the results of recording rainbow holograms in photothermoplastic media using a helium-neon laser. The dependences of the hologram characteristics on the width of the slit diaphragm are studied for the case of crater relief formation in the medium. The diffraction efficiency of the recorded holograms achieves 12% when the holographic sensitivity is no less than 105 cm2/J
[en] The He - Ne Laser is the first visible continuous wave laser that has been designed, constructed and operated in Iran. The first He - Ne operated after less than a year effort. Afterward, a few lasers have based one after another. However, the longest life time has been opproximately 400 hours. Due to many shortcomings such as availability of clean space and knowledgeable glass blowers, longer lifetimes have not been achieved yet. The continuous wave (CW) power of these lasers is about 1.5 m.W. These lasers are of the Brewster window type with external mirrors. Except for the Brewster Windows and the dielectric coated laser mirrors, the rest of the system was all built in this center and it is hoped that the other two parts also will be manufactured in the optics shop in the near future. (Author)