A simple two-ray interferometer based on a beamsplitter cube

Results of analysis of a very simple, compact interferometer for recording holographic diffraction gratings, which allows continuous tuning of the angle between the interfering beams from 0° to 80°, are presented. The device consists of a single optical element, a beamsplitter cube. The lengths of arms in such an interferometer are automatically equal, and tuning is accomplished by changing the angle of incidence of the beam on the input face. Formulas for calculating the principal characteristics of the device are derived. It is shown that using a cube material with a higher index of refraction allows increasing the beam diameter and broadening the tuning range. Recommendations on the device design are provided.     

Synthesis and nonlinear optical properties of donor-acceptor dyes based on triphenylpyrazolines as a donor block and dicyanoisophorone as acceptor

A series of donor-acceptor dyes based on polyfluoro-substituted triarylpyrazolines (as a donor block) and a dicyanoisophorone group (as an acceptor) were synthesized using the Knoevenagel condensation. The dyes have an absorption in the region of 509–514 nm and intense luminescence at 648–663 nm in chloroform with a large Stokes shift (up to 4410 cm^–1). Based on the synthesized dyes, chromophore–polymer (guest–host) films were obtained in a polycarbonate matrix with a chromophore content up to 27 wt.%. Poling of chromophore–polymer films was carried out in an electric field of a corona discharge and the coefficient of nonlinear optical response d₃₃ was measured by the second-harmonic generation method of the fundamental frequency of a Nd-YAG laser (1064 nm). The obtained films have a high initial thermal stability and a nonlinear optical response up to 80 pm V^–1, which persists up to 115 °С.