SU480002A1 - Apparatus for determining the quantum yield upon resonant excitation of luminescence - Google Patents

Description

This invention relates to a measurement technique. It can be used to control the quality of materials used in optical quantum generators, as well as on scientific and lighting measurements.

A device is known for determining the quantum yield upon resonant excitation of ruby luminescence, comprising a light source, a photometric sphere with inlet and outlet apertures coinciding with the optical axis, a diffusing screen, and a photo-peak.

In the known device, the mechanical strength of the MgO coated screen is unsatisfactory, and the diffusion reflection coefficient in the region of the resonant transition does not provide high accuracy and reliability of measurements.

The purpose of the invention is to increase the accuracy and reliability of measurements and reduce the complexity of measurements.

The goal is achieved by the fact that the screen is made in the form of an optical-mechanical unit consisting of an optically transparent diffuser of light (in the form of a plate, a turning prism or a flat-bent lens) and the screen itself (aluminum plate, matted or coated with MgO or lighting enamel) mounted on distance /

 () d, where d is the diameter of the screen, which exceeds the size of the test specimen in a section of 10-50% perpendicular to the optical axis.

FIG. 1 shows a diagram of the proposed device comprising a light source 1, an input 2 and an output 3 windows, a photometric sphere 4 within which sample 5 and an optomechanical assembly 6 are placed, and a photon receiver 7.

FIG. 2 shows schematically the construction of an opto-mechanical assembly comprising a diffuser 8 and a screen 9.

The device works as follows.

From source 1, a collimated beam of monochromatic light is applied through hole 2 to sample 5 (for example, a ruby crystal). Beam of light

reflected from the sample enters the surface of the photometric sphere 4, and the beam passing through the sample goes through hole 3 and falls onto the photon receiver 7. Behind sample 5 there is an optical-mechanical

node 6, having two fixed working positions: outside the beam and in the beam of light passing through the sample. This node performs two functions: firstly, it diffuses the light passing through the sample onto the walls of sphere 4 and,

secondly, it prevents the immediate

the illumination of the photodetector 7 by the light and the luminescence transmitted through the sample.

The degradation of characteristics is carried out according to the following scheme: when the optomechanical node is removed from the nook, the spectrum is scanned near the frequency of the resonant transition and the transmission spectrum is recorded, from which cr * is determined. With the introduction of the optomechanical assembly into the beam, scanning is also performed in the same spectral region, and the Ol-magnitude is determined from the spectrogram obtained. The magnitude of the quantum yield is determined by the formula

 "+ (1- /) j (l - / -) iX

p () - L (1-g) 1-g (1-2:

. H - 2) X -) H)

X ((1-2) - + + (1

(1-) p

X

where 5l / 5l is the ratio of the sensitivity of the photodetector to the exciting flux and flux of luminescence; g is the specular reflection coefficient of the sample in the region of the resonant transition; p is the effective diffuse reflectance of the optomechanical assembly.

The use of the optically transparent material of the diffuser 8 in the optomechanical assembly allows one to select the loss of light by absorption and achieve an effective diffuse reflectance, 95, even when the reflectance of the screen 9 is reduced by 30%.

Subject invention

Claims (3)

1. A device for determining the quantum yield under resonant excitation of luminescence, containing a photometric sphere with diametrically opposite inlet and outlet apertures coinciding with the optical axis, and a screen mounted behind the sample under study, characterized in that, in order to improve the accuracy and reliability of measurements, the screen is made in the form of an optical-mechanical one, consisting of an optically transparent light diffuser and the screen itself, set at a distance of 1 () d, where d is the screen diameter exceeding by 10-50% the largest overall size of the sample is in cross section perpendicular to the optical axis. 2. A device according to claim 1, characterized in that the diffuser is made, for example, in the form of a rectangular quartz prism with a polished edge along the beam. 3. The device according to paragraphs. 1 and 2, characterized in that the screen is made in the form of a metal plate with a reflective coating having a diffuse reflectance of not less than 0.7. shlifobanna and surface Otoazhaush, its coverage d