SU1562717A1 - Monochromator - Google Patents

Abstract

The invention relates to the field of optical spectral instrumentation. The aim of the invention is to increase the spectral transmittance and the monochromaticity of the emitted radiation. The radiation through the entrance slit 1 hits the collimator mirror 2 and then a parallel beam on the grid 3. The monochromator slots are located along the perpendicular to the plane of the main section of the grid 3 on opposite sides of this plane. A flat autocollimation mirror 4 is installed on the normal to the grating 3. The radiation with the wavelength λ diffracted on the grating 3 in the second order coincides with the emission of the same wavelength diffracted on the grating 3 in the reverse course in the first order. The normal to mirror 4 coincides with the normal to lattice 3. The addition of radiation of the same wavelength in the first and second order of diffraction increases the monochromaticity of the radiation. The monochromator can be used to study spectra with a low intensity of radiation and absorption. 1 il.

Description

. -. -, KAN

 sin if --7,

(one)

  ---- - simf, coso

6 -6,

de tf, Q are the angles formed with the normal to the diffraction grating by 3 projections of rays of the incident and diffracted beams onto the plane of its main section, respectively,

B is the angle formed between the incident beam and its projection onto the plane of the main section of the diffraction grating 3;

45

instead of sinif, the expression (3) is substituted for diffraction in the second order, then, taking into account that A is the same,

 Guo AN sin tf

Cos (s)

AN cos6

0

Thus, the projection of rays of the 1st order A, falling in the 2nd order into the exit slit, will go along the normal to the plane of the diffraction grating 3.

Having established perpendicular to the normal to the diffraction grating 3 on the path of the rays, a flat autocollimation mirror

4, thereby directing the beam diffracted in the first order so that its projection is directed along the normal to the diffraction grating 3 in the opposite direction, i.e. along the same path. In fact, the projection of the diffraction angle on the grating 3 in the forward direction and the reverse is the projection of the angle of incidence on the grating and is equal to 0. The beam itself in the vertical plane upon reflection changes the sign of the angle: (-b.

For the projection of radiation during diffraction on the grating 3 of the considered L in the first order in the reverse course, we can write /

  (five)

 / h

where 6- is the angle between the main plane and the 2nd-order radiation beam diffracted in the reverse direction.

Equating to, get 6 Ј, then the expression (3) can be written

. - AN

sin h -.

cos6

Instead of the right-hand side, the expression (2) is substituted, since D is the same for the 1st and 2nd order, then sin sin sin (f. This means that the projection of the diffraction angle on the grating 3 in the 1st pore Even in the reverse course, it coincides with the projections of the diffraction angle of the same A in the second order.

Consider the diffraction angles in the vertical plane for the 1st and 2nd order. For the 2nd - 6U, for the 1st, equating to 6, receive - 6-6. Thus, in the vertical plane, the diffraction angles in the direction of the collimator mirror 2 coincide, thereby the emission of the 1st and 2nd order of the same wavelength L, falling into the output slit 5. Thus, the total radiation at the output slit 5 1st and 2nd orders of the same wavelength of the same double dispersion.

Consequently, the radiation in the wavelength A, diffracted by the diffraction grating 3 in the second order, coincides with the emission of the same length, diffracted by the diffraction grating in the reverse direction in the first order,

Q

five

0

five

0

0 $ 0

17 °

if, in the 1st order, the projection of the diffraction angle on a flat plane of the main section of the diffraction grating 3 and the projection of the angle of incidence on the same plane in the reverse course are equal to zero.

Turning the diffraction grating 3 around an axis that is in its plane parallel to the strokes, i.e. perpendicular to the plane of the main section of the grating coinciding with the main plane of the monochromator, and at the same time having an autocollimation mirror 4 so that its normal coincides with the normal to the diffraction grating 3, the spectrum of the total radiation of the 1st and 2 is obtained at the output slit 5 th order, coinciding in wavelengths.

The increase in intensity in this case is achieved by the fact that the radiation of the 2nd order, diffracted by the diffraction grating on the collimator mirror and the exit slit, is folded with the radiation of the 1st order of the same wavelength, diffracted from the diffraction grating on the flat autocollimation a mirror and, reflected from it, again diffracted on the diffraction grating in the direction of the collimator mirror and the exit slit. Due to the addition of radiation of the same wavelength from the 1st and 2nd order at the exit slit, the monochromaticity of the radiation in relation to the known monochromator increases.

Thus, the proposed solution increases the intensity and increases the monochromaticity of the radiation emitted by the monochromator.

The drawing, as an example, shows the layout of the optical elements in which the flat autocollimation mirror 4 and the diffraction grating 3 are rigidly connected to each other, their normals drawn from the centers coincide and, when scanning, they jointly rotate around a common axis located in the plane of the diffraction grating parallel to its strokes.

The monochromator can be used to study spectra with a low intensity of radiation and absorption.

Claims (1)

Claims of the Monochrome Mountains, containing optically coupled entrance slit, collima 715627178 torus mirror, diffracted sieve and monochromaticity of the extracted izku, installed with the possibility of receiving, flat autocollimation the gate around the axis lying in a flat-mirror is installed perpendicularly diffraction lattice of the parallel of the normal, drawn from the center of the dash to the dashes, a flat autocollimation fractional lattice and with the possibility this mirror and the exit slit, in this case together with the diffraction the main focus of the collimator mirror-lattice around its axis of rotation, with la, its center and the center of the flat auto-this input and output slit size. the collimation mirror is located along the line connecting the centerpiece of the main section of the diffraction and parallel to the strokes of the diffraction grating, which distinguishes the Noah grating symmetrically relative to so that, in order to increase the co-main focus of the collimator mirror coefficient of the spectral transmittance of la ..