SU1693394A1 - Device for measuring relative spectral sensitivity of photo detectors - Google Patents

Abstract

This invention relates to the metrology of threshold characteristics of photodetectors and photoreceivers, and concerns the determination of relative spectral sensitivity (OFS). In order to improve the accuracy of measuring the OFS of small-sized photodetectors, a wavelength mixer was additionally inserted between the monochromator and the photoreceiver in the device for measuring the OFS containing consecutive emitters, modulators and monochromators, as well as photodetectors of the test and reference channels. The mixer consists of a collimator, the focus of which is the exit slit of the monochromator, we take in one half of the output stream of the collimator a node is installed that turns the image of the exit slit, and in the other - a non-turning optical compensator of the path length, two auxiliary flat mirrors angled to one another, and a projection lens, the focus of which is a photodetector, 4 Il.

Description

The invention relates to metrology, namely photometry, and can be used in determining the threshold characteristics of photoreceivers (AF) and photoreceiving devices (PD).

The aim of the invention is to improve the accuracy of measuring the relative spectral sensitivity (OFS) in the region of absorption bands in the atmosphere.

FIG. 1 is a block diagram of the device; in fig. 2 - energy distribution across the width of the slit in the absorption band, where L is the width of the exit slit of the monochromator,

Xi and Xa are the different positions of the studied FP of width b, DI and U2 corresponding to the positions Xi and Xs of the magnitudes of the signals; in fig. 3 - radiation energy distribution (E) across the width of the image of the output slit (L) in the case of work on the descending branch of the absorption band for unwrapped and wrapped (b) and total (c) images; in fig. 4 - an experimentally obtained device for the OFS phoS resistor PbS curve with a pad size of 0.05x0.05. mm

The device comprises a control unit 1, a radiation source 2, a modulator 3, a monochromator 4, a collimator lens 5, a first flat mirror 6, a wrapping node prism 7, a flat mirror turning mirror 8, a compensator prism 9, a flat mirror of the compensator 10, a second flat mirror 11 , projection lens 12, power supply unit 13 of the investigated FP, investigated FP 14, measuring path 15, the first recording device 16, block 17 of the power supply of the reference FP, the reference FP 18, measuring path 19 of the reference FP, the second recording device 20.

The device works as follows

The radiation of source 1 is modulated by the modulator 3 and illuminates the entrance slit of the monochromator 4. The radiation of the exit slit of the monochromator located in the focus of the objective 5 of the collimator is incident on a flat mirror b by a parallel beam, after which it is divided into two beams of equal intensity using prisms 7 and 9, Image the output slit in one beam is wrapped with a prism 7 and a flat mirror 8. The resulting extension of the beam travel is compensated in the second parallel beam with a compensator consisting of a prism 9 and flat mirrors 10 without wrapping the image. A flat mirror 11 directs parallel beams of light onto summing lens 12, which builds a summary image of the exit slit in the plane of placement of the sensitive areas of photodetectors 14 and 18.

Switching radiation from the receiver to the reference one is performed, for example, using a flat mirror (not shown).

The signal from the investigated photodetector 1 is measured in the measuring path 15 and is recorded by the recording device 16.

The signal from the reference photodetector 18, powered by power supply 17, is recorded in the measuring path consisting of the meter 19 and the recorder 20

Then, by adjusting the monochromator, another spectral interval is selected, and the procedure for measuring signals is repeated,

The method laid down in the device is based on a comparison of the spectral sensitivity of the Zyiss of the investigated receiver with the known spectral sensitivity of the reference receiver.

Zyoporn also consists in the fact that the photosensitive areas of the reference and test receivers are irradiated successively with the radiation of the exit slit of the monochromator, which separates a certain spectral interval Mi. With the help of recording equipment, the output signals of the reference fmx) and the tested (η) receivers are measured, respectively.

The monochromator is then rearranged to a different spectral interval, Afe, and the signal measurement process is repeated. Thus, signals are measured in the entire spectral range of interest to the researcher.

The value of the OFS, in each spectral interval allocated by the monochromator, is determined by the formula (for the case of a non-selective reference AF):

PYa m I max TI P I max

(one)

where F is the indication of the device registering the signal in the circuit of the studied OP or FPU;

TL is the indication of the instrument recording the signal in the reference OP circuit;

p I max the reading of the instrument recording the signal in the circuit of the studied OP at the maximum sensitivity;

m I max - the instrument reading the signal in the reference OP circuit

the maximum sensitivity of the OFS of the receiver under investigation, is determined by the formula

(D.

Thus, radiation arrives at the inputs of the receivers, the distribution of energy of which along the width of the gap is constant. In this case, the signal from the reference receiver does not depend on the initial installation of the receiver at one or another point B within the width of the output slit, which does not distort the shape of the OFS curve, especially in the absorption bands in the atmosphere.

The OFS curve for a receiver of 0.5x0.5 mm2 in size (FIG. 4) was obtained at the facility,

where the monochromator was an IK-31 infrared spectrometer monochromator, the reference receiver was an OAP-5M optoacoustic receiver, the signals were recorded using a Sht1516 digital voltmeter, which was retrieved using a DZ-28 microcomputer. All mirrors in the installation of aluminized.

When analyzing the OFS (FIG. 4), it can be seen that the distortion of the curve in the area

absorption bands in the atmosphere at a wavelength of 2.7 µm,

Claims (1)

The invention The device for measuring the relative spectral sensitivity of photodetectors and photodetectors, comprising a successively located on the optical axis an emitter, a modulator and a monochromator, also a reference-channel photoreceiver, connected to the first recording device, and a photodetector holder, connected to the second recording device, characterized in that, in order to increase accuracy, an additional cm is installed between the monochromator and the photo-receiver in the device Sitel wavelength, consisting of the collimator, the focus which is located at the exit slit of the monochromator, at an angle to one another of two auxiliary plane seals, the centers of which lie on the optical axis of the device, between which in one half of the aperture of the collimator there is a node that turns the image of the exit slit, and in the second half - non-turning optical a compensator for the path length of the beam, and a projection lens, the first auxiliary mirror being optically connected to the collimator, and the second auxiliary mirror to the projection lens, with In this case, the photodetector of the reference channel and the holder of the investigated photodetector are installed with the possibility of alternate optical sapping with a projection lens. Fig. / // 9 Have Mr. MF bseb91 IS II U 2.6 18 5.0 U 5.4 U Pieve A um