CN108459419B

CN108459419B - Filter pinhole alignment adjusting device and method based on grating diffraction

Info

Publication number: CN108459419B
Application number: CN201810045968.4A
Authority: CN
Inventors: 刘代中; 闫世森; 林强; 李红; 龚蕾; 张攀正; 朱宝强
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2018-01-17
Filing date: 2018-01-17
Publication date: 2020-05-05
Anticipated expiration: 2038-01-17
Also published as: CN108459419A

Abstract

The filter pinhole alignment adjusting device based on grating diffraction comprises: an insertable transmission grating disposed closely in front of the aperture of the filter; the detector is arranged in the direction of the diffracted light beams of the transmission grating to form an imaging system, and the output of the detector is connected with a computer. Computer controlled filter aperture requiring auto-collimation adjustment. The invention has the characteristics of simple equipment, easy adjustment and high precision.

Description

Filter pinhole alignment adjusting device and method based on grating diffraction

Technical Field

The invention belongs to the technical field of high-power laser devices, and particularly relates to a device and a method for adjusting the alignment of small holes of two spatial filters in one optical path in a high-power laser device.

Background

The traditional filter pinhole alignment technology adopts the steps that firstly, a concave lens 1 is inserted in front of a first spatial filter 2, as shown in figure 1, parallel laser is dispersed by the concave lens 1 and then completely fills a filter pinhole 3, then the outline of the filter pinhole 3 passes through a slightly larger filter pinhole 6 and finally images on a far-field detector 9 to obtain the central position information of the filter pinhole 3, then the concave lens 1 is removed, a concave lens 4 is inserted in front of a second spatial filter 5, as shown in figure 2, light completely fills the filter pinhole at the filter pinhole 6 and finally images on the far-field detector 9, and the far-field detector 9 records the central position information of the pinhole 6.

This solution has a high requirement for filter pinholes, which must be smaller than the latter, or else alignment cannot be achieved.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provides a filter pinhole alignment adjusting device based on grating diffraction, which has the characteristics of simple equipment, easiness in adjustment and high precision.

The technical solution of the invention is as follows:

a filter pinhole alignment adjusting device based on grating diffraction comprises a first filter pinhole, a second filter pinhole and a reflector which are sequentially arranged along a light path, and is characterized in that a transmission grating is arranged in front of the second filter pinhole in a manner of being tightly attached to the second filter pinhole, a second detector is arranged in the diffracted light beam direction of the transmission grating and is externally connected with a computer, and the computer is respectively connected with the first filter pinhole and the second filter pinhole.

The filter pinhole alignment method in the high-power laser device is realized by utilizing the filter pinhole alignment adjusting device based on grating diffraction, and is characterized by comprising the following steps:

① placing a transmission grating in close proximity to the second filter aperture in front of the second filter aperture such that the center of the second filter aperture coincides with the center of the transmission grating;

②, turning on the laser, reflecting the laser to the second detector through the projection grating, and transmitting the focal spot position to the computer by the second detector with the collected focal spot as the reference optical axis position;

③ placing the first concave lens on the light path between the laser and the first lens to make the transmission grating generate the first order diffraction light, the first filter aperture outline image on the second detector, the second detector transmits the first filter aperture outline image to the computer;

④ adjusting the first filter pinhole according to the first filter pinhole outline image presented on the computer to make the center position of the first filter pinhole outline image coincide with the reference optical axis position;

⑤ moving the first concave lens out of the optical path and moving the convex mirror into the optical path between the fourth lens and the reflector, so that the laser is reflected by the convex mirror and then enters the transmission grating through the second filter aperture, the transmission grating generates the first order diffraction light, the second filter aperture profile is imaged on the second detector, and the second detector transmits the second filter aperture profile image to the computer;

⑥ according to the second filter pinhole outline image presented on the computer, adjusting the second filter pinhole to make the center position of the second filter pinhole outline image coincide with the reference optical axis position.

Compared with the prior art, the invention has the following technical effects:

1) the first-order diffraction light generated by the transmission grating enables the outline of the small hole of the filter to be imaged on the detector through the transmission grating arranged in front of the small hole of the filter in a close fit mode, the outline of the small hole of the filter is accurately adjusted into the center of the detector according to the outline image of the small hole on the detector, and operation is simple.

2) The method has the characteristics of simple equipment, easy adjustment and high precision.

Drawings

FIG. 1 is a schematic diagram of an optical path of a conventional filter aperture alignment adjustment device aligned with a first filter aperture.

Fig. 2 is a schematic diagram of an optical path of a conventional filter aperture alignment adjustment device aligned with a second filter aperture.

FIG. 3 is a schematic diagram of an optical path of a filter aperture alignment adjustment device aligned with a first filter aperture based on transmission grating diffraction according to the present invention.

FIG. 4 is a schematic diagram of an optical path of a filter aperture alignment adjustment device aligned with a second filter aperture based on transmission grating diffraction according to the present invention.

In the figure: 1-first concave lens 2-first lens 3-first filter aperture 4-second lens 5-second concave lens 6-third lens 7-second filter aperture 8-fourth lens 9-reflector 10-far field beam shrinking lens 11-first detector 12-second detector 13-transmission grating 14-convex reflector

Detailed Description

The present invention will be further described with reference to the following examples and drawings, but the scope of the present invention should not be limited thereto.

Referring to fig. 3 and 4, there are shown schematic light path diagrams of the filter pinhole alignment adjustment device based on grating diffraction according to the present invention, and it can be seen from the drawings that the filter pinhole alignment adjustment device based on grating diffraction according to the present invention comprises:

a transmission grating 13 closely attached to the front of the filter aperture 7;

the second detector 12 is arranged in the direction of the diffracted light beam of the transmission grating 13 to form an imaging system, and the output of the second detector 12 is connected with a computer;

computer controlled filter aperture 3 and filter aperture 7 that require auto-collimation adjustment.

The filter pinhole alignment method in the high-power laser device is realized by using the filter pinhole alignment adjusting device based on grating diffraction, and is characterized by comprising the following steps:

① placing the transmission grating 13 in close proximity to the second filter aperture 7 in front of it, so that the centre of the second filter aperture coincides with the centre of the transmission grating 13;

②, the laser is turned on, the laser is reflected to the second detector 12 through the transmission grating 13, the second detector 12 takes the collected focal spot as the reference optical axis position, and transmits the focal spot position to the computer to confirm the optical axis position;

③ inserting the first concave lens 1 into the light path between the laser and the first lens 2 to make the transmission grating 13 generate the first order diffraction light, the first filter pinhole 3 outline image on the second detector 12, the second detector 12 transmits the first filter pinhole 3 outline image to the computer;

④ adjusting the first filter pinhole 3 according to the first filter pinhole 3 outline image presented on the computer to make the first filter pinhole 3 outline image center position coincide with the reference optical axis position;

⑤ moving the first concave lens 1 out of the optical path, moving the convex mirror 14 into the optical path between the fourth lens 8 and the reflector 9, making the laser reflected by the convex mirror 14 and then emitted into the transmission grating 13 through the second filter aperture 7, making the transmission grating 13 generate the first order diffraction light, imaging the second filter aperture 7 profile on the second detector 12, and transmitting the second filter aperture 7 profile image to the computer by the second detector 12;

⑥ according to the outline image of the second filter pinhole 7 presented on the computer, the second filter pinhole 7 is adjusted so that the center position of the outline image of the second filter pinhole 7 coincides with the reference optical axis position.

In conclusion, the device and the method have the characteristics of simple equipment, easy adjustment and high precision.

Claims

1. A filter pinhole alignment adjusting device based on grating diffraction realizes a filter pinhole alignment method in a high-power laser device, the device comprises a first lens, a first filter pinhole, a second lens, a third lens, a second filter pinhole, a fourth lens and a reflector which are sequentially arranged along a light path, a transmission grating is arranged in front of the second filter pinhole in a manner of being clung to the second filter pinhole, a second detector is arranged in the diffracted beam direction of the transmission grating, the second detector is externally connected with a computer, and the computer is respectively connected with the first filter pinhole and the second filter pinhole; the method is characterized by comprising the following steps:

②, turning on the laser, reflecting the laser to the second detector through the transmission grating, and transmitting the collected focal spot to the computer as the reference optical axis position;