SU532279A1 - Holographic interferometer - Google Patents

Description

one

The invention relates to optical instrumentation and can be applied in aerodynamics, hydrodynamics, thermophysics, in measurement technology in the qualitative and quantitative studies of inhomogeneities in transparent media.

There are known holographic interferometers ij, fi of which the separation of the light beam occurs before its passage through the cube. Interferograms obtained using such interferometers are easily decoded (they are identical to the interferograms obtained on a Zehnder-Mach interferometer).

However, such interferometers are cumbersome, highly sensitive to vibrations, and there are difficulties in adjusting when using a pulsed source.

Holographic shear interferometers 2} are known, in which the separation of a light beam is carried out after its passage through the inhomogeneity under study. Shear interferometers are used to study phase objects.

Also known is a holographic shear interferometer containing

a coherent radiation point, an optical system for illuminating an object, a diffuse aspirator, a system for dividing a beam into two channels, a recording medium after the object j | h.

The shift interferometers are small in size and are made, for example, in the form of attachments to the shadow device. In addition, they are more resistant to the effects of vibration and other external influences.

Common disadvantages of holographically shear interferometers are the difficulty of deciphering shear interferograms and the small size of the field being observed.

To improve the image quality and obtain an interferogram without shifting the wave fronts in the interlaced interferometer, the diffuse scatterer is located in one of the channels of the system for beam separation.

The purpose of the scatterer located in one of the channels of the system for beam separation is that it forms a scattered reference wave, whose spatial frequency spectrum is much wider than the spatial frequency spectrum of the object. Behind

this, using the double exposure method, makes it possible to obtain high-quality interferograms without shifting wave fronts.

A variant is possible: a diffuse diffuser, in which the surface of one of the optical elements in one of the channels of the system can be diffusing for beam separation.

FIG. 1 shows a variant of the optical scheme of the proposed device; in fig. Figure 2 shows another variant in which the glass diffuse-scattering plate is absent in the scheme, but, for example, a reflecting, scattering plate is installed instead of a mirror.

The scheme includes coherent light source 1, lenses 2 and 3, work zone 4, lenses 5 and b, light separator 7, swivel mirrors 8 and 9, photo layer 10, glass diffusion-scattering plate 11.

The operation of the device is as follows.

The light beam from the coherent light source 1 is expanded by a telescopic system (lenses 2 and 3), shines through the working area 4 and is directed to the light separator 7, is divided into two beams, one beam is scattered by the glass plate 11 and passes on the photo layer 10. At that on the photo layer 10 a hologram of the object located in the working zone 4 is fixed. After that the object; removed from the working area 4 and the second exposure of the photo layer 10 is performed.

5 holograms, an interferogram is obtained without shifting wave fronts.

Claims (3)

1. Author's certificate of the USSR 266103, cl. GDI B 9/02, 1968, 2.J.Opt-Soc Amev. V. 5b, W 7, 19b, p. 865. ; j5 3. Quantum Electronics, 1973, No. 2 (14) 80-83. 2 .one. fvt.t