SU1677508A1 - Holographic interferometer - Google Patents

Abstract

The invention relates to a control and measuring technique and can be used to study objects using holographic interferometry. The aim of the invention is to expand the operational capabilities by ensuring the operation of the interferometer both in the mode of two exposures and in real time. The radiation from laser 1 is broadened by micro-lens 2 and hits the lens 5 placed on object 9 in attachment unit 8. The outer surface of the lens 5, made in the form of a positive meniscus, being semi-reflective, reflects a part of the beam from / iy, which then, having reflected from the beam splitter 4 and passed the oculus p 6, becomes a collimated reference beam when recording holograms on the recording medium 7. Other the part of the beam that passes the lens 5 is reflected from the object 9. The lens 5 and the ocular 6, form from this part of the radiation an image of the object in the plane of the recording medium 7, which is the object beam when recording holograms. 1 il. YO O VI VI ate about 00

Description

The invention relates to a measuring and control technique and can be used in the study of objects by the method of holographic interferometry.

The purpose of the invention is to expand the operational capabilities by enabling the interferometer to operate both in the two-exposure mode and in real-time mode.

The drawing shows a diagram of a holographic interferometer.

The interferometer contains a laser 1, a microbugging 2, a pinhole 3, a light divider 4, a lens 5, an eyepiece 6, a recording medium 7, a mount 8 of an objective 5 to an object 9.

The interferometer works as follows.

The center of the semi-reflective spherical surface of lens 5 is aligned with the focus of micro-lens 2, which forms the illuminating light flux with a spherical wave front of the same radius, which is successively passed and cleared by the diaphragm 3, beam splitter 4, is partially reflected from lens 5 and returns to beam splitter 4 along the same optical of the way. The focus of the eyepiece 6 is combined with the focus of the reflected light from the lens 5 and the beam splitter 4 of the light flux. The semi-reflective surface of the lens 5 and the ocular p 6 form the afocal system of the reference beam. The radius of the other surface of the lens 5 is determined from the formula of a thin LENS f G1G2 / (P-1HG2-G1), GD6 f - the focal distance of the lens 5; n is the refractive index of the lens material; n, yy - the radii of the spherical surfaces of the lens, in which f rz (in the reverse direction of the rays). At the same time receive p G2-G2 / P. Since the focus of the eyepiece 6 is aligned with the focus of the part of the illuminating light flux that passes twice through the lens 5 and is reflected from the object 9, the eyepiece and the lens form the telescopic system of the object beam forming the image of the object in the plane of the recording medium 7.

The mount 8 of the lens 5 to the object under study 9 is made in the form of three or more supports of rubber-based magnetic elastomers. The design of the supports ensures a tight fit to the uneven surface, the elasticity of the supports compensates for small deformations of the object under loading and ensures geometric stability. For attachment to diamagnetic materials it is necessary

use auxiliary magnets mounted from the unlighted side of the object.

To obtain real-time interferograms, a hologram of the unperturbed state of the object is initially obtained; after photo processing, it is set in the same place, the object is loaded, and the interferogram of the surface deformations is recorded during the exposure by recording the reconstructed image.

Interferometers of the sequential type are resistant to inhomogeneities of air gaps and oscillations of foundations, they can be used to study transparent media, if a flat mirror or diffusely reflecting light is installed behind the objective and lens.

surface. The compensating properties of the hologram allow the use of a large-diameter lens 5 made of optical polystyrene. To reduce the light loss, the beam splitter 4 of

Claims (1)

the interferometer can be eliminated, while the optical axis of the objective 5 is inclined to the axis of the illuminating counting flux at a small angle, the surface of the material of the point aperture 3 is specularly reflective and inclined at an angle to the axis of the laser. The de-alignment errors of lens 5 are negligible and are compensated for in the reconstructed image. Invention Formula A holographic interferometer containing a laser and a micro-lens located along the path of radiation, a pinhole, an attachment point to the object, and a recording medium; characterized in that, in order to expand operational capabilities by providing work also in real time, it is equipped with a lens made in the form of a positive meniscus, the radii n and n of the spherical surfaces of which satisfy the ratio n п2 (1-1 / п), where n is the refractive index of the objective material, and the surface with a radius gy of curvature is semi-reflective, and installed in the mount so that the semi-reflective surface faces the radiation incident on it, and its center of curvature coincides with the focus of the microscope objective todelitelem placed along the radiation between the flyweights and the lens diaphragm and the eyepiece, mounted downstream successively reflected from the beam splitter and the lens so that the lens and ocular focal points coincide.