阅读说明：本技术 激光光束自动整形装置 (Automatic shaping device for laser beam ) 是由 丁海波 孙畅 郭一君 于 2021-08-17 设计创作，主要内容包括：本发明公开了激光光束自动整形装置,该装置由光束调制模块和自动控制模块组成,所述光束调制模块包括空间光调制器(1)、第一凸透镜(2)、分束器(3)和第二凸透镜(4),所述自动控制模块包括空间光调制器(1)、光束质量分析仪(5)和计算机(6),所述计算机(6)与空间光调制器(1)、光束质量分析仪(5)通过电缆连接形成闭环反馈系统。本发明以空间光调制器实施激光光束的波前整形,实现任意目标光斑的整形效果；通过引入光束质量分析仪形成闭环反馈系统,提高激光光束的整形质量,降低人工操作的难度与工作量。(The invention discloses an automatic laser beam shaping device which comprises a beam modulation module and an automatic control module, wherein the beam modulation module comprises a spatial light modulator (1), a first convex lens (2), a beam splitter (3) and a second convex lens (4), the automatic control module comprises the spatial light modulator (1), a beam quality analyzer (5) and a computer (6), and the computer (6) is connected with the spatial light modulator (1) and the beam quality analyzer (5) through cables to form a closed-loop feedback system. The invention uses the spatial light modulator to implement the wave front shaping of the laser beam, and realizes the shaping effect of any target light spot; a closed-loop feedback system is formed by introducing a beam quality analyzer, so that the shaping quality of the laser beam is improved, and the difficulty and the workload of manual operation are reduced.)

1. The utility model provides an automatic shaping device of laser beam which characterized in that: the automatic beam modulation system comprises a beam modulation module and an automatic control module, wherein the beam modulation module comprises a spatial light modulator (1), a first convex lens (2), a beam splitter (3) and a second convex lens (4), the automatic control module comprises the spatial light modulator (1), a beam quality analyzer (5) and a computer (6), and the computer (6) is connected with the spatial light modulator (1) and the beam quality analyzer (5) through cables to form a closed-loop feedback system.

2. The automatic shaping device of claim 1, wherein: the spatial light modulator (1) is fixed on the in-situ rotating table, and the mirror surface arrangement direction of the spatial light modulator is consistent with the polarization direction of incident laser.

3. The automatic shaping device of claim 1, wherein: the first convex lens (2) and the second convex lens (4) construct a standard 4f system for adjusting the size of the emergent laser beam, and the ratio of the spot diameter of the emergent laser to the spot diameter of the incident laser is f₂/f₁。

4. The automatic shaping device of claim 1, wherein: the beam splitter (3) adopts a non-polarized flat beam splitter or a non-polarized beam splitting cube, and the distance between the beam splitter and the first convex lens (2) is less than the focal length f of the first convex lens (2)₁。

5. The automatic shaping device of claim 1, wherein: the optical path between the placing position of the beam quality analyzer (5) and the first convex lens (2) is equal to the focal length f of the first convex lens (2)₁。

Technical Field

The invention relates to the field of laser application, in particular to an automatic shaping device for a laser beam.

Background

With the rapid development of lasers, various types of lasers have been widely applied to the fields of microscopic imaging, optical measurement and micro-nano processing. In order to ensure the quality of imaging and processing, laser beam shaping becomes a core technology in the field.

To solve this key problem, beam shaping schemes based on devices such as slits, variable diaphragms, micro-lens arrays, deformable mirrors, spatial light modulators, etc. are gradually developed. The silicon-based liquid crystal spatial light modulator is based on the Fourier optical theory, can actively adjust incident laser to implement phase modulation, thereby realizing high-precision and full-range beam shaping, and is widely applied to holographic imaging, phase difference correction in a microscopic system and multi-beam parallel laser processing. However, in the practical implementation process, the standard monitoring means is lacked to evaluate the beam shaping effect, and the conventional method mainly depends on manual observation and judgment before system construction, so that the common operator is difficult to master and the shaping quality is not uniform. During the operation of the system, once the state of the incident laser changes, the incident laser cannot be found in real time and corrected quickly.

Therefore, an effective solution is needed to solve the difficulty of automatic control in beam shaping, provide an intelligent operation scheme for ordinary users, enhance the automation degree of the system, and improve the beam shaping effect.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide the automatic shaping device of the laser beam, which is convenient to operate and has high automation degree.

The technical scheme is as follows: the invention provides an automatic laser beam shaping device which comprises a beam modulation module and an automatic control module, wherein the beam modulation module comprises a spatial light modulator, a first convex lens, a beam splitter and a second convex lens, the automatic control module comprises the spatial light modulator, a beam quality analyzer and a computer, and the computer is connected with the spatial light modulator and the beam quality analyzer through cables to form a closed-loop feedback system.

Furthermore, the spatial light modulator is fixed on the in-situ rotating table, and the mirror surface arrangement direction of the spatial light modulator is consistent with the polarization direction of the incident laser. The first convex lens and the second convex lens construct a standard 4f system for adjusting the size of the emergent laser beam, and the ratio of the spot diameter of the emergent laser to the spot diameter of the incident laser is f₂/f₁. The beam splitter is a non-polarizing flat plate beam splitter or a non-polarizing beam splitting cube, and the distance between the beam splitter and the first convex lens is less than the focal length f of the first convex lens₁. The optical path between the placing position of the beam quality analyzer and the first convex lens is equal to the focal length f of the first convex lens₁。

The spatial light modulator modulates the incident laser through the loading holographic phase diagram, the beam quality analyzer monitors the modulated emergent laser in real time, and the loading pattern of the spatial light modulator is adjusted according to the comparison result of the target beam and the emergent beam.

Has the advantages that: compared with the prior art, the invention adds the beam quality analyzer to provide real-time monitoring and form a closed-loop feedback system, and has the following advantages:

1. the automation degree of the beam shaping device is improved, the use difficulty of an operator is reduced, and possible laser safety accidents are avoided by removing manual operation.

2. The unified machine judgment replaces manual judgment, so that the method is not only suitable for the incident laser of any facula pattern, but also improves the quality of the emergent laser after beam shaping.

3. The spatial light modulator is used for implementing wave front shaping of the laser beam, and the shaping effect of any target light spot is realized.

Drawings

FIG. 1 is a schematic diagram of the structure of the apparatus;

fig. 2 is a flow chart of the operation of the apparatus.

Detailed Description

As shown in fig. 1, the laser beam automatic shaping device of the present embodiment is composed of a beam modulation module and an automatic control module. The light beam modulation module comprises a spatial light modulator 1, a first convex lens 2, a beam splitter 3 and a second convex lens 4, and the automatic control module comprises the spatial light modulator 1, a light beam quality analyzer 5 and a computer 6.

In this embodiment, the spatial light modulator 1 is fixed to the in-situ rotation stage, so that the mirror surface arrangement direction is consistent with the polarization direction of the incident laser.

In this embodiment, the first convex lens and the second convex lens constitute a standard 4f system for adjusting the size of the outgoing laser beam, and the ratio of the spot diameter of the outgoing laser beam to the spot diameter of the incoming laser beam is f2/f 1.

In this embodiment, the beam splitter 2 is a non-polarizing plate beam splitter or a non-polarizing beam splitting cube, the splitting ratio is less than 10: 90 (reflection: transmission), and the distance between the beam splitter and the first convex lens is less than the focal length f1 of the first convex lens.

In this embodiment, the optical path length between the placement position of the beam quality analyzer 5 and the first convex lens is equal to the focal length f1 of the first convex lens.

In this embodiment, the computer 6 is connected with the spatial light modulator 1 and the beam quality analyzer 5 through cables to form a closed-loop feedback system, and the provided control program can acquire measurement data of the beam quality analyzer in real time, calculate an appropriate holographic phase diagram and automatically load the holographic phase diagram to the spatial light modulator until the coincidence rate of the measurement data and the target beam reaches a preset threshold value or more.

As shown in fig. 2, a specific working flow of the automatic laser beam shaping device in this embodiment includes:

1) adjusting and fixing the installation angle of the spatial light modulator 1 to make the installation angle consistent with the polarization direction of incident laser;

2) inputting a target light beam pattern, which can be in a picture format or equation description, from a control program port of the computer 6, and setting a threshold value of a comparison result, wherein the recommended value is 99%;

3) after starting the operation program, the computer 6 automatically calculates the holographic phase diagram and loads the holographic phase diagram to the spatial light modulator 1;

4) the light beam quality analyzer 5 transmits the detection result back to the computer 6, and the control program compares the detection result with the comparison result of the target group;

5) if the comparison result is higher than the preset threshold value, the control program keeps loading the pattern until the operation is finished; and if the comparison result is lower than the preset threshold value, the control program returns to the step 3, and the hologram is recalculated and loaded until the comparison result exceeds the threshold value.

Example 1

This embodiment is directed to laser holographic imaging. The incident laser is continuous laser after beam expanding treatment, and the wavelength is 532 nanometers. According to the requirement of the imaging size, the focal lengths of the first convex lens 2 and the second convex lens 4 are 250 mm and 500 mm respectively, the beam splitter 3 selects a flat plate beam splitter with the splitting ratio of 50: 50, and finally the target pattern can be presented on the image plane of the second convex lens 4.

Example 2

This embodiment is directed to wavefront shaping for microscopic imaging. The incident laser is femtosecond laser processed by beam expansion, and the wavelength is 488 nanometers. Because the emergent laser needs to be further coupled to a focusing objective lens, the focal lengths of the first convex lens 2 and the second convex lens 4 are 500 mm and 400 mm respectively, the beam splitter 3 selects a beam splitting cube with the beam splitting ratio of 10: 90, the length-diameter ratio of the focus can be finally adjusted at the focus of the second convex lens 4, and the aberration influence after the observation depth is increased is reduced.

Example 3

The embodiment is directed to femtosecond laser parallel processing. The incident laser is femtosecond laser processed by beam expansion, and the wavelength is 800 nanometers. Because the emergent laser needs to be further coupled to the focusing objective lens, the focal lengths of the first convex lens 2 and the second convex lens 4 are 500 mm and 400 mm respectively, the beam splitter selects a beam splitting cube with the beam splitting ratio of 10: 90, and finally, a uniform multi-focus array can be formed on the focal plane of the subsequent focusing objective lens.