We dealt with the problem of shading of dense polydispersed aerosol particles during registration of holographic images. It is a suggested technique that is based on the three-wave holographic recording of a cloud of micron and submicron particles. We present the calculated and experimental results of effective reconstruction of cloud particles with concentration of up to 100 × 106 / cm3. Simultaneous use of three-wave scheme provides complete analysis of the resulting holograms and more effectively restore the volume distribution of dense aerosol formatting.
The results of experimental and theoretical studies aimed at creating of the device for high-precision measurements of the extended optical fiber length are presented. Now the length of fibers with a length about tens kilometer is measured with an accuracy of several meters. However, in the case of some interferometric measurements it is necessary to know lengths of long fibers with an accuracy of millimeters. The equipment by means of which it can be done is rather expensive. In this work the description of the simple device developed by us which allows measuring a fiber length with extreme accuracy to millimeters is submitted, the results of measurements and the assessment of their accuracy are shown. The principle of work consists of the registration of a phase shift when you change settings of parameters of the laser radiation extended through an optical fiber. The effectiveness of measuring technique was checked on segments of optical fiber of a predetermined length with accuracy about 1 mm.
The influence of thermal deformation processes on the phase-matching temperature bandwidth of nonlinear frequency conversion in different uniaxial and biaxial crystals is determined by using the results of calculations and experimental measurements. It is shown that the temperature bandwidths in borate crystals differ considerably in the case of different methods of nonlinear crystal fixation.
The results of transmitted wavefront distortion correction are presented for a YAG:Nd3+ active element with a diameter 45 mm. Halftone mask and proximity printing were used for fabrication of the freeform corrector. Experimental results show a three-fold decrease of the wavefront distortion. Because the corrector presented a high damage threshold, it can be used with high power laser systems.