CN104483018A - Light path structure of small asymmetric high-spectrum-resolution grating monochromator - Google Patents

Abstract

The optical path structure of an asymmetric small-scale high spectral resolution grating monochromator belongs to the technical field of spectral analysis instruments. And the turntable; the light beam emitted by the incident slit is irradiated on the collimating objective lens for collimation, after the beam is collimated, it is dispersed and split by the plane grating, and the dispersed light beam is converged by the converging objective lens, and then focused on the exit slit after refracting the light path by the deflection mirror , so as to obtain quasi-monochromatic light, the plane grating is fixed on the turntable, and the monochromatic light of different wavelengths is output at the exit slit by rotating the grating through the turntable. The system of the invention has the advantages of compact structure, small volume, light weight, and simple processing and assembly. The converging objective lens can obtain a larger focal length so that the spectral line dispersion rate of the monochromator is significantly improved. The folding mirror folds the optical path inside the instrument to effectively compress the volume of the instrument, which can effectively reduce the astigmatism of the system and improve the energy concentration of the output spectrum of the instrument.

Description

Optical path structure of an asymmetric small high spectral resolution grating monochromator

technical field

The invention belongs to the technical field of spectral analysis instruments, and relates to an optical path structure of an asymmetric small-scale high-spectral resolution grating monochromator.

Background technique

A monochromator is a spectroscopic instrument used to obtain quasi-monochromatic light. It is a basic test equipment for spectral analysis and spectral characteristic measurement. It is widely used in scientific research, production and quality control.

With the continuous development of modern science and technology, miniaturization, light weight, portability and high resolution have gradually become the mainstream trend of monochromator development. The conventional monochromator adopts the Czerney-Turner optical path structure. The optical path of this structure is relatively symmetrical. The collimating objective lens of the instrument and the mirror focal length of the imaging object are similar or even equal. To improve the spectral line dispersion rate of the instrument, it is necessary to increase the collimation of the instrument. The focal length of the objective lens and imaging objective lens increases the volume and weight of the instrument.

Contents of the invention

In order to solve the problems existing in the prior art, the present invention provides an optical path structure of an asymmetric small-scale high spectral resolution grating monochromator. In this structure, within a limited volume range, the converging objective lens can obtain a larger focal length so that The spectral line dispersion rate of the monochromator is significantly improved, and it has the characteristics of high resolution, small volume, and compact structure.

The technical solution adopted by the present invention to solve technical problems is as follows:

An optical path structure of an asymmetrical small scale high spectral resolution grating monochromator, the structure includes: incident slit, collimating objective lens, plane grating, converging objective lens, exit slit and turntable, the structure also includes: catadioptric reflection Mirror; the light beam emitted by the incident slit is irradiated on the collimating objective lens for collimation. After the beam is collimated, it is dispersed and split by the plane grating. In order to obtain quasi-monochromatic light, the flat grating is fixed on the turntable, and the flat grating is rotated by the turntable so that monochromatic light of different wavelengths is output at the exit slit.

The beneficial effects of the invention are: the system of the invention is compact in structure, small in volume, light in weight, and simple in processing and assembly. In a limited volume range, the converging objective lens can obtain a larger focal length, so that the spectral line dispersion rate of the monochromator is significantly improved. The folding mirror folds the optical path inside the instrument to effectively compress the volume of the instrument, and when the cylindrical mirror is used as the folding mirror, it can effectively reduce the astigmatism of the system and improve the energy concentration of the output spectrum of the instrument.

Description of drawings

Fig. 1 is a schematic diagram of an optical path structure of an asymmetrical small-scale high spectral resolution grating monochromator of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the optical path structure of an asymmetric small-scale high spectral resolution grating monochromator of the present invention includes an incident slit 1, a collimating objective lens 2, a plane grating 3, a converging objective lens 4, and a refracting mirror 5 , the exit slit 6 and the turntable 7; the collimating objective lens 2 and the converging objective lens 4 all adopt concave spherical reflectors, and the focal length of the converging objective lens 4 is much greater than the focal length of the collimating objective lens to improve the spectral line dispersion rate of the instrument; the plane grating 3 adopts a reflective plane Grating; folding reflector 5 is used to fold the optical path inside the instrument to reduce the volume of the instrument, either a plane reflector or a cylindrical reflector (can eliminate system astigmatism); turntable 7 is used to rotate the plane grating 3 to Monochromatic light of different wavelengths is output at the exit slit. The light beam emitted from the incident slit 1 is irradiated on the collimating objective lens 2. After the beam is collimated, it is dispersed and split by the plane grating 3. The dispersed light beam is converged by the converging objective lens 4, and then focused on the exit slit 6 after refracting the optical path by the deflection mirror 5. to obtain quasi-monochromatic light.

Implementation example 1:

In the optical path structure of the present invention, the working band of the monochromator is 200-850nm, and the object-side numerical aperture is 0.1; the collimating objective lens 2 and the converging objective lens 4 are concave spherical reflectors, and the radii of curvature are respectively 90mm and 193mm, and the off-axis angle 8° and 30° respectively, focal lengths are 45.2mm and 80.8mm respectively; planar grating 3 adopts reflective ruled grating whose grating constant is 1/600mm; cylindrical reflector is used as refracting reflector 5 to eliminate system astigmatism , The radius of curvature of the cylindrical mirror is 294mm.

Through optical design software tracking, the theoretical resolution of the optical path structure of an asymmetrical small-scale high spectral resolution grating monochromator constructed in this example can reach 1nm, and the optical path length and width are 56mm×47mm.

Claims (4)

1. a light channel structure for the small-sized high spectral resolution grating monochromator of asymmetric, this structure comprises: entrance slit, collimator objective, plane grating, convergence object lens, exit slit and turntable, is characterized in that, this structure also comprises: refluxing reflection mirror; The light beam irradiation that described entrance slit sends collimates in collimator objective, by plane grating dispersion light splitting after beam collimation, dispersed light beam is assembled by assembling object lens, exit slit place is focused on after refluxing reflection mirror turns back light path, thus acquisition quasi-monochromatic light, plane grating is fixed on turntable, by turntable rotational plane grating, the monochromatic light of different wave length is exported at exit slit place.

2. the light channel structure of the small-sized high spectral resolution grating monochromator of a kind of asymmetric as claimed in claim 1, is characterized in that, described collimator objective and convergence object lens are concave spherical mirror; Assemble the focal length of focal length much larger than collimator objective of object lens.

3. the light channel structure of the small-sized high spectral resolution grating monochromator of a kind of asymmetric as claimed in claim 1, is characterized in that, described plane grating is reflective planar grating.

4. the light channel structure of the small-sized high spectral resolution grating monochromator of a kind of asymmetric as claimed in claim 1, is characterized in that, described refluxing reflection mirror is cylindrical mirror.