Laser interference etching optical device with actively adjustable period

Abstract

The utility model discloses a laser interference etching optical device with an actively adjustable period, and belongs to the technical field of laser processing optical systems. The laser interference etching optical device comprises a laser processing light source, a lens, a shaping device, a fixed-time beam expander and a focus lens which are arranged in sequence, emergent light of the laser processing light source is a collimated light beam; the lens is used for converting emergent light of the laser processing light source into a point light beam serving as a to-be-shaped light beam; the shaping device is used for shaping a to-be-shaped light beam into multiple light beams with positive divergence angles and is arranged on the displacement mechanism; the fixed-magnification beam expander is used for carrying out negative angle conversion on emergent light of the shaping device; the distance between the focus lens and the fixed-time beam expander is smaller than the focal length of the fixed-time beam expander, and the focus lens is used for focusing emergent light of the fixed-time beam expander. According to the utility model, the purpose of multi-beam interference can be achieved, active and continuous regulation and control of an interference pattern period can be realized, and the regulation range is large.

Description

Technical Field

[0001] The utility model relates to the technical field of laser processing optical systems, in particular to a laser interference etching optical device with actively adjustable period. Background Art

[0002] Laser beam interference refers to the use of laser coherence to separate two or more laser beams from the same laser source through a beam splitter (such as a semi-transparent and semi-reflective mirror, a prism, a diffraction grating, etc.), or to generate them from independent but coherent lasers, and then make these two or more laser beams pass through different optical paths and then re-superimpose them at a certain point or surface in space to achieve the purpose of interference.

[0003] The reason why laser is used is that laser is a highly coherent light source, and its beam has the characteristics of good monochromaticity (i.e. single frequency), strong directionality, high brightness, and long coherence length. These characteristics enable the laser beam to maintain good coherence in space and time, that is, the light waves of different parts have a stable phase relationship, which is the basis for the interference phenomenon. Laser beam interferometry technology is widely used in many fields such as precision measurement, optical element and thin film property analysis, surface morphology and roughness measurement, quantum optics and basic research, industrial quality control and non-destructive testing, as well as lidar and remote sensing due to its high precision and real-time performance.

[0004] Among them, the laser interference etching method uses the interference pattern generated by the interference of laser beams as a template, and selectively irradiates and removes the material in a specific area to prepare a periodic or specific pattern of micro-nano structures on the substrate. This method combines the characteristics of laser etching technology and laser interference technology and has many significant advantages. First, laser interference can easily obtain submicron or even nanometer-level periodic structures. At the same time, because the interference effect is global, large-area and uniform pattern etching can be achieved, which is very suitable for large-scale production needs. Secondly, compared with traditional photolithography, laser interference etching does not require expensive photomasks. Pattern etching can be achieved by directly manipulating the laser beam, which reduces costs and simplifies the process flow. It is particularly suitable for rapid prototyping and customized production. In addition, laser interference etching can process a variety of hard, soft, transparent, opaque, metal, non-metal and other materials, including some materials that are resistant to traditional etching methods. Finally, by adjusting laser parameters (such as wavelength, power, pulse width, etc.) and interference conditions (such as optical path settings, phase difference, etc.), the period, shape, depth, etc. of the etched pattern can be flexibly changed to achieve precise control of the micro-nano structure. Therefore, in recent years, laser interference etching technology has been widely used in microelectronics, optoelectronics, biomedicine, optical components, data storage, surface modification and other fields.

[0005] However, since the prisms used in the interference system to collimate multiple divergent light beams into multiple parallel light beams are difficult to design and manufacture, the existing laser interference processing systems are mainly based on dual-beam interference solutions. However, compared with dual-beam interference, multi-beam interference has higher fringe contrast and sharpness, and the light and dark contrast is more significant, which is very beneficial for interference etching. In addition, multi-beam interference has a finer fringe structure, which is particularly important for high-precision micro-nano processing. Moreover, multi-beam interference has strong stability and anti-interference capabilities, and the fluctuation or interference of a single beam has relatively little effect on the overall interference pattern. This is because the superposition of multiple coherent beams averages the instability of a single beam to a certain extent, which is beneficial to improve the stability and reliability of the entire interference system. Utility Model Content

[0006] The purpose of the utility model is to provide a laser interference etching optical device with an actively adjustable period in response to the existing technical status, which can not only achieve the purpose of multi-beam interference, but also realize active and continuous regulation of the interference pattern period with a large adjustment range.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A laser interference etching optical device with active and adjustable period, comprising a laser processing light source, a lens, a shaping device, a fixed-magnification beam expander and a focusing lens;

[0009] The output light of the laser processing light source is a collimated light beam;

[0010] The lens is arranged before the laser processing light source, and is used to convert the outgoing light of the laser processing light source into a point light beam as the light beam to be shaped;

[0011] The shaping device is arranged before the lens, and is used to shape the light beam to be shaped into multiple light beams with positive divergence angles, and the number of light beams in the multiple light beams is greater than 2. The shaping device is arranged on a displacement mechanism, and the displacement mechanism is used to drive the shaping device to move along the optical axis of the light beam to be shaped;

[0012] The fixed-power beam expander is arranged before the shaping device, and is used to transform the output light of the shaping device into a negative angle to form multiple light beams with negative divergence angles;

[0013] The focusing mirror is arranged before the fixed-power beam expander, and the distance between the focusing mirror and the fixed-power beam expander is less than the focal length thereof. The focusing mirror is used to focus the output light of the fixed-power beam expander.

[0014] Furthermore, the fixed-power beam expander performs negative angle transformation on the outgoing light of the shaping device, and the conversion rate thereof is -0.5 to -2.

[0015] Furthermore, the displacement mechanism is an electric displacement stage, and also includes a control system, which is electrically connected to the displacement mechanism and the laser processing light source, and is used for real-time dynamic adjustment of the period of the light spot interference pattern formed on the processing surface of the product to be processed.

[0016] Furthermore, the displacement mechanism is a manual slide for manually adjusting the period of the light spot interference pattern formed on the processing surface of the product to be processed.

[0017] Furthermore, the laser processing light source is a single-mode light source or a multi-mode light source.

[0018] Furthermore, the shaping device is a microlens array or a diffractive optical element or a grating.

[0019] Furthermore, the lens is a negative lens or a positive lens or an emitting lens.

[0020] The beneficial effects of the utility model are:

[0021] The utility model firstly shapes the light beam to be shaped into multiple light beams with positive divergence angles through a shaping device, then transforms the output light of the shaping device into a negative angle through a fixed-power beam expander to form multiple light beams with negative divergence angles, and finally focuses the output light of the fixed-power beam expander through a focusing lens, thereby constructing a laser interference processing system that causes multiple light beams to interfere with each other. At the same time, in the processing project, the shaping device is continuously moved along the optical axis of the light beam to be shaped through a displacement mechanism, and the period of the light spot interference pattern formed on the processing surface of the product to be processed is continuously adjusted, thereby realizing active adjustment of the interference period.

[0022] According to the above design, the utility model can not only achieve the purpose of multi-beam interference and improve the contrast and accuracy of interference etching, but also realize active and continuous regulation of the interference pattern period with a large adjustment range, thus having a wide range of applications and extremely high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of a laser interference etching optical device with an actively adjustable period according to the utility model;

[0024] Figure 2 This is a comparison diagram of the spot interference pattern when the divergence angle of the shaped light beam changes after the fixed-magnification beam expander undergoes negative angle transformation and reaches the focusing lens.

[0025] Label instructions: 1. Laser processing light source, 2. Lens, 3. Shaping device, 4. Displacement mechanism, 5. Fixed-magnification beam expander, 6. Focusing lens, 7. Control system. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below with reference to the accompanying drawings and implementation examples. It should be understood that the specific examples described here are only used to explain the utility model and are not used to limit the utility model.

[0027] See also Figure 1 As shown, a laser interference etching optical device with active and adjustable period includes a laser processing light source 1, a lens 2, a shaping device 3, a fixed-magnification beam expander 5 and a focusing lens 6.

[0028] The emitted light of the laser processing light source 1 is a collimated light beam. Optionally, in this embodiment, the laser processing light source 1 is a single-mode light source or a multi-mode light source, which is selected according to the processing requirements.

[0029] The lens 2 is arranged before the laser processing light source 1, and is used to convert the outgoing light of the laser processing light source 1 into a point beam as the beam to be shaped. Optionally, in this embodiment, the lens 2 is a negative lens or a positive lens or an emission lens, which is selected according to the processing requirements.

[0030] The shaping device 3 is arranged before the lens 2, and the shaping device 3 is used to shape the light beam to be shaped into multiple light beams with positive divergence angles, and the number of light beams in the multiple light beams is greater than 2. The shaping device 3 is arranged on the displacement mechanism 4, and the displacement mechanism 4 is used to drive the shaping device 3 to move along the optical axis of the light beam to be shaped. Optionally, in this embodiment, the shaping device 3 is a microlens array or a diffractive optical element or a grating, which is selected according to the processing requirements.

[0031] The fixed-power beam expander 5 is arranged before the shaping device 3, and is used to transform the output light of the shaping device 3 into a negative angle to form a multi-beam with a negative divergence angle. For the output light of the fixed-power beam expander 5, its divergence angle is jointly determined by the distance between the shaping device 3 and the fixed-power beam expander 5 and the transformation rate of the fixed-power beam expander 5. Optionally, in this embodiment, the transformation rate of the fixed-power beam expander 5 for transforming the output light of the shaping device 3 into a negative angle is -0.5 to -2, which is selected according to the processing requirements.

[0032] The focusing mirror 6 is arranged before the fixed-power beam expander 5, and the distance between the focusing mirror 6 and the fixed-power beam expander 5 is less than its focal length. The focusing mirror 6 is used to focus the output light of the fixed-power beam expander 5 to increase the energy density and realize interference etching. It should be pointed out that since the incident light of the focusing mirror 6 is a multi-beam with a negative divergence angle, there is a phenomenon of early focusing, so the convergent light spot on its front focal plane is not the smallest light spot, and multiple laser focal points will be formed in front of its front focal plane, and the number of focal points matches the number of light beams in the output light of the shaping device 3.

[0033] In the above technical scheme, as one implementation scheme, the displacement mechanism 4 is an electric displacement table, and also includes a control system 7. The control system 7 is electrically connected to the displacement mechanism 4 and the laser processing light source 1, and is used to dynamically adjust the period of the light spot interference pattern formed on the processing surface of the product to be processed in real time; as another implementation scheme, the displacement mechanism 4 is a manual slide, which is used to manually adjust the period of the light spot interference pattern formed on the processing surface of the product to be processed.

[0034] Specifically, based on the laser interference etching optical device with active periodicity adjustment, the steps of the laser interference etching method with active periodicity adjustment are as follows:

[0035] The processing surface of the product to be processed is made to coincide with the front focal plane of the focusing mirror 6, and a spot interference pattern is formed on the processing surface of the product to be processed. Then, the product to be processed is moved along a preset path relative to the focusing mirror 6, and the target features are processed on the processing surface of the product to be processed according to the spot interference pattern.

[0036] More specifically, during the processing, the shaping device 3 is continuously moved along the optical axis of the light beam to be shaped, and the period of the light spot interference pattern formed on the processing surface of the product to be processed is continuously adjusted, wherein:

[0037] If it is necessary to reduce the period of the light spot interference pattern, the shaping device 3 is moved on the displacement mechanism 4 toward the direction close to the laser processing light source 1;

[0038] If it is necessary to increase the period of the light spot interference pattern, the shaping device 3 is moved on the displacement mechanism 4 in a direction away from the laser processing light source 1 .

[0039] The reason why continuous adjustment can be achieved is as follows:

[0040] The light beam to be shaped (spot light beam) is incident on the shaping device 3 at a certain angle θ, and the shaping device 3 will superimpose a divergence angle θ1 on the light beam to be shaped (spot light beam). Therefore, when the shaped light beam is incident on the fixed-power beam expander 5, its divergence angle is θ+θ1. It should be clear that when the distance between the shaping device 3 and the fixed-power beam expander 5 changes, that is, when the position of the shaping device 3 changes, this angle relationship still holds, that is, the shaped light beam is always incident on the fixed-power beam expander 5 at a divergence angle of θ+θ1.

[0041] However, the movement of the shaping device 3 along the optical axis of the light beam to be shaped will cause the distance between it and the fixed-power beam expander 5 to change, so that the light beam to be shaped (point light beam) with the same divergence angle will be incident on different positions of the fixed-power beam expander 5 after being shaped, and the divergence angle of the shaped light beam after passing through the fixed-power beam expander 5 will also be different, and finally enter the focusing lens 6. After the shaped light beam is transformed into a negative angle by the fixed-power beam expander 5, the divergence angle after reaching the focusing lens 6 is different, and the focusing effect changes accordingly (such as Figure 2),in:

[0042] When the divergence angle of the shaped light beam after negative angle transformation by the fixed-power beam expander 5 and after reaching the focusing lens 6 is small, the period of the light spot interference pattern is large;

[0043] When the divergence angle of the shaped light beam after negative angle transformation by the fixed-power beam expander 5 and reaching the focusing lens 6 is large, the period of the light spot interference pattern is small.

[0044] In general, the utility model first shapes the light beam to be shaped into multiple light beams with a positive divergence angle through the shaping device 3, and then transforms the output light of the shaping device 3 into a negative angle through the fixed-power beam expander 5 to form multiple light beams with a negative divergence angle, and finally focuses the output light of the fixed-power beam expander 5 through the focusing lens 6, thereby constructing a laser interference processing system that causes multiple light beams to interfere with each other. At the same time, during the processing, the shaping device 3 is continuously moved along the optical axis of the light beam to be shaped through the displacement mechanism 4, and the period of the light spot interference pattern formed on the processing surface of the product to be processed is continuously adjusted, thereby realizing active adjustment of the interference period.

[0045] According to the above design, the utility model can not only achieve the purpose of multi-beam interference and improve the contrast and accuracy of interference etching, but also realize active and continuous regulation of the interference pattern period with a large adjustment range, thus having a wide range of applications and extremely high application value.

[0046] The present invention is not limited to the above-mentioned specific implementation modes. A person skilled in the art can implement the present invention in various other specific implementation modes according to the contents disclosed in the present invention. Therefore, any design that adopts the design structure and concept of the present invention and makes some simple changes or modifications shall fall within the scope of protection of the present invention.

Claims

1. A laser interference etching optical device with active adjustable period, characterized in that: Including laser processing light source, lens, shaping device, fixed-magnification beam expander and focusing lens; The output light of the laser processing light source is a collimated light beam; The lens is arranged before the laser processing light source, and is used to convert the outgoing light of the laser processing light source into a point light beam as the light beam to be shaped; The shaping device is arranged before the lens, and is used to shape the light beam to be shaped into multiple light beams with positive divergence angles, and the number of light beams in the multiple light beams is greater than 2. The shaping device is arranged on a displacement mechanism, and the displacement mechanism is used to drive the shaping device to move along the optical axis of the light beam to be shaped; The fixed-power beam expander is arranged before the shaping device, and is used to transform the output light of the shaping device into a negative angle to form multiple light beams with negative divergence angles; The focusing mirror is arranged before the fixed-power beam expander, and the distance between the focusing mirror and the fixed-power beam expander is less than the focal length thereof. The focusing mirror is used to focus the output light of the fixed-power beam expander.

2. The laser interference etching optical device with active adjustable period according to claim 1, characterized in that: The fixed-power beam expander performs negative angle transformation on the outgoing light of the shaping device at a conversion rate of -0.5 to -2.

3. The laser interference etching optical device with active adjustable period according to claim 1, characterized in that: The displacement mechanism is an electric displacement stage, and also includes a control system, which is electrically connected to the displacement mechanism and the laser processing light source, and is used for real-time dynamic adjustment of the period of the light spot interference pattern formed on the processing surface of the product to be processed.

4. The laser interference etching optical device with active adjustable period according to claim 1, characterized in that: The displacement mechanism is a manual slide, which is used to manually adjust the period of the light spot interference pattern formed on the processing surface of the product to be processed.

5. The laser interference etching optical device with active adjustable period according to any one of claims 1 to 4, characterized in that: The laser processing light source is a single-mode light source or a multi-mode light source.

6. The laser interference etching optical device with active adjustable period according to any one of claims 1 to 4, characterized in that: The shaping device is a microlens array or a diffractive optical element.

7. The laser interference etching optical device with active adjustable period according to any one of claims 1 to 4, characterized in that: The lens is a negative lens or a positive lens or a transmitting lens.

Images