SU1486792A1 - Device for recording interferograms - Google Patents

Description

The invention relates to the field of optical instrumentation, in particular to interferometers used to measure the characteristics of photosensitive materials. The purpose of the invention is to simplify the design of the device by combining the functions

2

focusing and reflecting with one element - a mirror (convex or concave). The light flux from the coherent radiation source 1 is divided by the beam-splitting mirror 2 into the first transmitted and the second reflected light beams. The first light beam is reflected sequentially from the first concave mirror 3 and the second concave mirror 4 and is directed to the photosensitive material attached to the holder 6, the second light beam is reflected from the convex mirror 5 and interferes with the first one. The interference pattern thus obtained is recorded on the photosensitive material. 1 il.

The invention relates to an optical instrument, namely the interferometers used to measure the characteristics of photosensitive materials. ,;

The purpose of the invention is to simplify the design of the device by combining? focus and reflection functions

the element is a mirror (convex and concave).

The drawing shows a diagram of the device.

The device contains an optically coupled coherent light source 1 and a beam-splitting mirror 2 for dividing the light flux into the first light beam transmitted

'through the mirror and the second light beam, reflected, installed first successively in the course of the first light beam, the first convex mirror

3 and the second concave mirror 4, installed along the second light beam, the third convex mirror 5 and the holder 6 of the photosensitive material mounted at the intersection of the axes of the first and second light beams reflected from the second and third mirrors, respectively

4 and 5. The second and third mirrors 4 and

5 are installed with the possibility of rotation around the holder in the plane passing through the axes of the first and second light beams, reflected

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3

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four

respectively from mirrors 4 and 5. The ratios of the radii of curvature of the mirrors satisfy the condition

; K _th ; Kz = £ § --- s

and;

_8a

2a + b

where K,, K5 ,, K. _a - the radii of curvature

respectively the first, second and third mirrors 3,4 and 5;

a is the distance from the second mirror 4 to the place of installation of the holder 6, equal to the distance from the third mirror 5 to the place of installation of the holder 6;

B is the distance from the first mirror 3 to the second mirror 4;

and - the aperture angle of convergence of the first light beam reflected from the second mirror 4, equal to the divergence angle of the second light beam reflected from the third mirror 5.

The device works as follows.

The light flux from the coherent radiation 1 of radiation by means of a beam-splitting mirror 2, operating according to the principle of dividing the front of a light wave, is divided into the first light beam passing through the mirror 3 and the second light beam reflected from the mirror 3 with the same amplitudes. The first light beam, reflected in series from the mirrors 3 to 4, and the second light beam, reflecting from mirror 5, are directed to the material under study, which is located in the holder 6.

Mirrors 4 and 5, directing light beams on the material under study, simultaneously perform the functions of optical focusing systems and diverging light beams, which simplifies the design of the device.

In the interference pattern recorded on the surface of photosensitive30

ten

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25

35

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45

50

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material studied, the period of the bands varies in the range of ° ^T 2 8 2η (y-i)

to a, = ^_ 2 “5Ϊπ" (ί + ΰ3 '

where 8, and is the period of interference fringes;

- the angle of inclination of the axial beam;

and - aperture angle of divergence (convergence) of the beam;

Ά - radiation wavelength. Joint rotation of mirrors 4 and

5 around the holder 6 in the plane passing through the axes of the first and second light beams, reflected respectively from mirrors 4 and 5 and mirrors 2 and 3, around the axis of the first light beam, the period of interference fringes is changed. In this case, point B, from which one beam diverges, and point C, to which another beam converges, remain symmetrical with respect to the surface of the material under study. If the change in the angle of inclination <Y to the surface of the light-sensitive material is made by the value yo (= 2 and upward (decrease), then the lowest (high) frequency, which is recorded at this setting, is equal to the highest (low) frequency of the previous installation. Additional the extension of the frequency range of the recorded interferograms is provided by turning the holder

6 to 90 °.

Claims (1)

Claim A device for recording interferograms containing an optically coupled coherent light source and a beam-splitting mirror for dividing the light flux into the first light beam passing through the beam-splitting mirror, and a second light beam reflected from the beam-splitting mirror mounted in series along the first light beam first and second mirrors in the course of the second light beam, the third mirror and the holder, designed for installation, of a photosensitive material in 5 1486792 the intersection of the axes of the first and second light beams so that the normal to the material surface is the bisector of the angle between the axes of the first and second light beams ®, the second and third mirrors are installed with the possibility of synchronous rotation around the holder in the plane passing through the axes of the first and ιθ of the second light beams, characterized in that, in order to simplify the design, the first and third mirrors are convex, the second mirror is concave, and the ratio of the radii of curvature of the mirrors satisfy the condition Κ, ί k ,; E _b . _Cg -2- and; . ²⁰ G8 and / 2, where K _<9 K3 - the radii of curvature respectively περ6 second, third and third mirrors; the distance from the second mirror to the place of installation of the holder, equal to the distance from the third mirror to the place of installation of the holder, the distance from the first mirror to the second mirror, the aperture angle of convergence of the first light beam,. reflected from the second mirror, equal to the angle of divergence of the second light beam reflected from the third mirror. ί