SU1557452A1 - Apparatus for holographic recording of interferograms - Google Patents

Abstract

The invention relates to holography, in particular to methods of holographic interferometry, and can be used for interferometric measurements in various aspects of science and technology. The purpose of the invention is to increase the contrast of the interference fringes and increase the time of observation of the interference pattern when registering interferograms using the real-time method. The goal is achieved by changing the design of the heating device of the photothermoplastic recording cell. The heating device is in the form of a glass plate with a double-sided metallic coating, with one layer with a resistance of 300 to 500 ohms serving to provide a predetermined preheating, and a short-term developing impulse of additional heating is applied to the other layer with a resistance of 20 to 40 ohms. 2 Il.

Description

The invention relates to holography, namely to holographic interferometry, and can be used for interferometric measurements in various fields of science and technology.

The purpose of the invention is to increase the contrast of the interference fringes and increase the time of observation of the interference pattern in real time.

Figure 1 shows a cell of a photothermoplastic recording device for holographic recording of interferograms using the real-time method; Fig. 2 is a graph of temporal dependences of the temperature of the heater (curve A) and the diffraction efficiency of the holograms of the initial state. (curve B).

The device contains (Fig. 1) a photothermoplastic (FTP) layer 1, a metal layer 2 with a resistance of 300-500 Ohm, a cell body 3, contact points kt glass plate 5, a metal layer 6 of resistance

By using an ohm corona-forming frame 7, a corona electrode 8, a control unit 9, a heating power unit 10, a heating pulse power unit 11 and a high-voltage unit 12.

The FTP layer 1 is pressed from the side of the substrate to the metal layer 6 by resistance Ohm, to which a short-term developing impulse of additional heating is applied. On the other side of the glass plate 5, a metallic layer 2 is applied with a resistance of 300-500 Ohm, by applying a voltage to which the preheating temperature is controlled through the contact leads. Corps cell 3 and the corona frame 7 is made of PCB. The corona electrode 8, which is a tungsten filament d of 20-30 µm, is located at a distance of 15-18 mm from the surface of the carrier. The process of recording holographic interferograms on the proposed device is carried out as follows.

The preheating temperature is set which is 60 ° C for the thermoplastic layer of the PTPN made on the basis of the prepolymer of diallyl isophthalate. The preheating temperature is controlled by applying voltage to the first layer 2. When the heating device reaches the set temperature, high potential is applied corona electrode 8 with simultaneous exposure of the carrier surface by converging beams. After the charging is completed, the latent image is produced by applying a short-term thermal impulse of additional heating to the second layer 6 of the plate 5. The preheating temperature is determined by the glass transition temperature of the material of the thermoplastic layer and is 5–10 ° C lower than its value.

The duration of the developing pulse can vary from 1 to 9 seconds, and its value controls the temperature of the final additional heating. The magnitudes of the resistances of metalized layers are universal for all types of FPNF, and their values

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selected on the basis of the power of the power sources operating from transformers TPP-2 -127 / 220-50, TAG-127 / 200-50, ensuring the continuity of the coating (with a layer resistance of more than 500 ohms, the layer thickness corresponds to tens of angstroms and possible discontinuity of the coating) and minimizing the amount of overshoot during positional control of the preheating temperature.

The ratio between the resistances of the layers (the resistance of one layer is an order of magnitude less than the resistance of the other) is due to the achievement of the required rate of final heating.

Compared with the known device, it has been possible to increase the contrast of interference fringes by 0.2 relative units. and increase the observation time of the interference pattern from 15 minutes to 1 hour without loss of contrast.

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A device for topographic recording of interferograms on a photothermoplastic carrier containing optically coupled coherent radiation source, an optical system for forming a reference and objective beams, and a photothermoplastic carrier consisting of a glass substrate, a conductive layer, a photothermoplastic layer, a control unit with parallel connected power units heating, high-voltage unit, and the output of the power supply unit heating is connected to koprovodyushchy layer, the high-voltage unit is connected to the mouth An over-carrier corona electrode, characterized in that, in order to increase the contrast of interference fringes and increase the time of observation of interference patterns in real time, a second conductive layer is additionally applied on the other side of the glass substrate; 300-500 and 20-AO Ohm, and an additional pulse power supply unit is connected to the second conductive layer, its input is connected to the output of the control unit.

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Editor A. Ogar

Compiled by E. Dorofeeva Tehred A. Kravchuk

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FIG. 2

Proofreader M.Samborsk

Claims (1)

Claim A device for holographic recording of interferograms on a photothermrplastic carrier, containing an optically coupled coherent radiation source, an optical system for forming reference and objective beams, and a photothermoplastic carrier, consisting of 35 conductive glass substrates. 'layer, a photothermoplastic layer, a control unit with a parallel connected heating power supply, a high voltage block, the output 40 of the heating power supply being connected to the same conductive layer, the high voltage block connected to a corona electrode mounted above the carrier, characterized in that, with the aim of increasing contrast interference fringes and increase the time of observation of interference patterns in real time, on the other side of the glass substrate 5θ a second conductive layer is additionally applied, pr moreover, both layers are made of metal with resistances of 300-500 and 20-40 Ohms, with an additional block of pulse power supply of heating connected to the second conductive layer, the input of which is connected to the output of the control unit.