CN-121994352-A - Off-axis beam quality detection method based on super surface

Abstract

The invention relates to the technical field of laser beam quality detection, and particularly discloses an off-axis beam quality detection method based on a super surface, which is realized based on a system comprising a light source, a light source and a light source, wherein the light beam to be detected emitted by the light source is red light with unknown wave front phase distribution; the system comprises a beam processing system, an off-axis beam quality analysis system and an off-axis detection light path, wherein the beam processing system consists of a polarizer and a 1/4 wave plate, the beam splitting system is used for splitting beams in a working area of the beam splitting system at a certain angle, the off-axis beam quality analysis system consists of a CCD camera and an analysis computer, and the off-axis detection light path is used for receiving off-axis beams deflected by a super-surface and guiding the off-axis beams to a beam quality analyzer (such as the CCD camera, a wavefront sensor and the like). The off-axis beam quality detection method based on the super surface does not need to remove or move the original optical element, greatly simplifies the fault checking flow, saves a great amount of debugging time and labor cost, and is particularly suitable for an integrated, sealed or high-stability optical path system.

Inventors

• LI LI
• LIU XINGDONG
• WANG YU
• TAN PENG
• HU CHENGPENG

Assignees

• 哈尔滨工业大学

Dates

Publication Date

20260508

Application Date

20260309

Claims (4)

1. 1. An off-axis beam quality detection method based on a super-surface is characterized by comprising the following steps: The device comprises a light source (1), wherein a light beam (2) to be detected emitted by the light source (1) is red light with unknown wave front phase distribution; the light beam processing system consists of a polarizer (3) and a 1/4 wave plate (4); a beam splitting system for splitting the beam in its working area at an angle; The off-axis beam quality analysis system consists of a CCD camera (7) and an analysis computer (8); The off-axis detection light path (6) is used for receiving off-axis light beams deflected by the super surface, guiding the off-axis light beams to the light beam quality analyzer, and obtaining quality information maps of light intensity distribution, wave front phase and the like of the whole light beam section through image splicing and algorithm reconstruction; The detection method comprises the following steps: The ultra-surface moves to a certain area of the light beam under control, and off-axis phase modulation is applied to the micro-area light beam so as to deflect the micro-area light beam to a detection light path; the detection unit acquires the quality parameters of the micro-area light beam; Then the super surface moves to the next area, and the process is repeated; and finally, synthesizing a complete two-dimensional distribution map of the beam quality through data processing.
2. 2. The method of claim 1, wherein the light source (1) is a helium-neon laser with a wavelength of 632.8 nm.
3. 3. A method for off-axis beam quality detection based on a subsurface as claimed in claim 1, wherein the polarizer (3) in the beam processing system is used only when the polarization state of the beam is unknown, and the component can be omitted if the polarization state of the beam is known.
4. 4. A method of off-axis beam quality detection based on a subsurface, as claimed in claim 1, wherein the beam splitting system is comprised of a subsurface element (5) equipped with a scanning drive, the subsurface element (5) being comprised of an array of sub-wavelength scale nanostructures.

Description

Off-axis beam quality detection method based on super surface Technical Field The invention relates to the technical field of laser beam quality detection, in particular to an off-axis beam quality detection method based on a super surface. Background With the rapid development of optical technology, the number of integrated optical elements in a complex laser optical path system is increasing. Processing errors, modulation errors, or degradation of performance due to long-term use of each optical device (e.g., lens, mirror, modulator, etc.) may cause degradation of beam quality, such as wavefront distortion, uneven light intensity distribution, mode degradation, etc. These localized or cumulative defects can severely impact the final output performance of the optical path and the reliability of the experimental results. Currently, beam quality detection mainly depends on a coaxial detection method, that is, a beam to be detected needs to be directly incident into a beam quality analyzer (such as a wavefront sensor, a beam profiler, etc.) for measurement. However, such instruments are typically bulky and must be inserted into the optical path to function. When fault diagnosis is carried out on a complex light path system, the optical element is often required to be repeatedly disassembled and assembled to be inserted into the detection equipment, and a problem device is positioned in a section-by-section removal mode. The process is complex in operation, time-consuming and labor-consuming, and easy to introduce an adjustment error, so that the stability of the system is affected. In addition, the coaxial detection mode is difficult to realize real-time and online quality monitoring, early warning can not be performed immediately when a problem occurs, and investigation can only be performed afterwards, so that the reliability and maintenance efficiency of the system are reduced. In order to reduce interference to the main optical path, an off-axis detection technique (such as using a beam splitter to sample) has been developed, but it usually splits the whole beam of light, so that the power of the main optical path is significantly reduced, and the sampled beam may still be affected by aberration of the beam splitter, so that it is difficult to realize high-spatial resolution local diagnosis. Therefore, there is an urgent need for a beam quality detection means that can be non-invasive, high spatial resolution, and real-time on-line to cope with the debugging, monitoring and maintenance requirements of complex optical path systems. Disclosure of Invention In order to solve the technical problems, the invention is realized by the following technical scheme that the off-axis beam quality detection method based on the super surface is realized based on the following system, and the system comprises the following steps: The light source emits a light beam to be detected, and the light beam to be detected is red light with unknown wave front phase distribution; The light beam processing system consists of a polarizer and a 1/4 wave plate; a beam splitting system for splitting the beam in its working area at an angle; The off-axis beam quality analysis system consists of a CCD camera and an analysis computer; An off-axis detection light path is used for receiving off-axis light beams deflected by the super surface, guiding the off-axis light beams to a light beam quality analyzer (such as a CCD camera, a wavefront sensor and the like), and obtaining quality information maps of light intensity distribution, wavefront phase and the like of a full light beam section through image stitching and algorithm reconstruction; The system has the core that the flexible regulation and control capability of the super surface to the wave front phase of the light beam is utilized, the scanning movement mechanism and the detection analysis unit are combined to form a set of online diagnosis device which can be integrated in the light path, the scanning step length is equal to the size parameter of the working area of the super surface, when the light beam quality detection is carried out on visible light, the step length is smaller than 100 mu m, and for a light spot with the diameter of 2mm, the scanning area of 100 mu m is equivalent to dividing the light beam into 400 areas for sampling reconstruction, the detection precision can meet the requirement of reconstructing the wave front, and the scanning area is not overlapped in the scanning process, but the jump can not occur continuously. The detection method comprises the following steps: The ultra-surface moves to a certain area of the light beam under control, and off-axis phase modulation is applied to the micro-area light beam so as to deflect the micro-area light beam to a detection light path; the detection unit acquires the quality parameters of the micro-area light beam; Then the super surface moves to the next area, and the process is repeated; and finally, synthesiz