Device for monitoring output power of linear polarization laser in real time

Abstract

The utility model relates to a device for monitoring the output power of a linear polarization laser in real time, which comprises a carrier, a purification assembly and a power sampling assembly are sequentially arranged on the carrier at intervals along the transmission direction of incident laser, the purification assembly comprises an optical adjusting frame A, and a Brewster polaroid pile is arranged on the optical adjusting frame A; a residual light collector is arranged in a direction in which incident laser is reflected by the Brewster polaroid stack; the power sampling assembly comprises an optical adjusting frame B, a Brewster window sheet is arranged on the optical adjusting frame B, and a power detector is arranged in the direction in which the incident laser is reflected by the Brewster window sheet; the included angle between the mirror surface of the Brewster polarizer stack and the transmission direction of the incident laser is a Brewster angle, and the included angle between the mirror surface of the Brewster window sheet and the transmission direction of the incident laser deviates from the Brewster angle. The device has the advantages of being reasonable in structural design, capable of achieving high-precision and low-interference real-time monitoring of the output power of the linear polarization laser, easy to assemble and debug and the like.

Description

Technical fields:

[0001] This utility model relates to the field of laser energy measurement technology, specifically to a device for real-time monitoring of the output power of a linearly polarized laser. Background technology:

[0002] Linearly polarized lasers are widely used in aerospace, automotive, shipbuilding, electronics, and medical fields. In actual production, different materials require different laser powers for processing. Therefore, the real-time output power of the laser directly affects the product processing quality, making real-time monitoring of the laser's output power an important aspect of laser technology. Traditionally, integrated laser power measuring instruments are used to detect the output power of linearly polarized lasers. This technology offers high accuracy and a wide range of detectable laser power and wavelength. However, processing must be stopped before power measurement can be performed, causing some delays in the production process and making it unsuitable for applications requiring real-time laser power monitoring.

[0003] Existing technologies mainly employ two methods for detecting laser power: rotating optical blade sampling and resonant cavity tail mirror sampling. The rotating optical blade sampling method requires a sampling optical blade that rotates at high speed with a motor along the laser output path. As the rotating optical blade passes through the laser path, it reflects a portion of the laser light onto a focusing lens. After being focused by the lens, the laser light is incident on a photodetector. Rotating optical blade sampling requires the motor's rotation period to be much shorter than the photodetector's response time, and also requires a constant reflective cross-sectional area of ​​the sampling optical blade. While these methods can detect power in real time, sampling instability may occur due to the influence of equipment manufacturing processes and the environment, and they cannot be used for high-repetition-rate pulse power detection. Furthermore, tail mirror sampling requires a dielectric mirror with stable low transmittance as one of the mirrors in the resonant cavity. The transmitted light from this mirror is focused onto the detector by a lens, and the detector's output electrical signal is linearly related to the incident light power. However, this technology requires the installation of corresponding components during laser production, and the components are costly, hindering large-scale adoption.

[0004] It should be noted that the above content falls within the inventor's technical knowledge and does not necessarily constitute prior art. Utility Model Content:

[0005] The purpose of this invention is to solve the problems existing in the prior art and provide a device for real-time monitoring of the output power of a linearly polarized laser. It has the advantages of reasonable structural design, high-precision and low-interference real-time monitoring of the output power of a linearly polarized laser, and easy assembly and debugging.

[0006] This utility model achieves the above objectives by adopting the following technical solutions:

[0007] A device for real-time monitoring of the output power of a linearly polarized laser includes a carrier on which a purification component and a power sampling component are sequentially spaced along the incident laser transmission direction. The purification component includes an optical adjustment frame A with a Brewster polarizer stack and a residual light collector positioned in the direction of reflection of the incident laser through the Brewster polarizer stack. The power sampling component includes an optical adjustment frame B with a Brewster window and a power detector positioned in the direction of reflection of the incident laser through the Brewster window. The angle between the mirror surface of the Brewster polarizer stack and the incident laser transmission direction is a Brewster angle, while the angle between the mirror surface of the Brewster window and the incident laser transmission direction deviates from the Brewster angle, thus reflecting a portion of the incident laser. The power detector is used to detect the incident laser power reflected by the power sampling component.

[0008] The optical adjustment frame A is provided with a bracket A, and the bracket A is provided with a channel A for the incident laser to pass through. The front end of the bracket A is mounted on the optical adjustment frame A, and the rear end is provided with a lens mounting seat A. Multiple Brewster windows A are arranged sequentially on the lens mounting seat A. The Brewster windows A are inclined and the multiple Brewster windows A form a Brewster polarizer stack. The upper end of the bracket A is provided with a reflection opening A.

[0009] The optical adjustment frame B is provided with a bracket B, which has a channel B for the incident laser to pass through. The front end of the bracket B is mounted on the optical adjustment frame B, and the rear end is inclinedly provided with a lens mounting seat B. The lens mounting seat B is provided with a Brewster window B, and the upper end of the bracket B is provided with a reflection opening B.

[0010] The present invention adopts the above technical solution, which can bring the following beneficial effects:

[0011] By sequentially placing a purification component and a power sampling component along the transmission direction of the incident laser, the purification component allows the P-polarized component of the incident laser to pass through without loss, while most of the S-polarized component is reflected, thereby reducing the S-polarized component in the incident laser and improving the purity of the P-polarized component. Then, the power sampling component reflects a specific proportion of the incident laser, and a power detector monitors the power of the incident laser in real time. This method achieves high-precision, low-interference real-time monitoring of the output power of a linearly polarized laser. It is easy to assemble and debug, applicable to various types of linearly polarized lasers, and can accurately and effectively measure the real-time output power of the laser while the laser processing equipment is operating, allowing for timely adjustments to processing parameters to ensure processing quality. Attached image description:

[0012] Figure 1 This is a schematic diagram of the device structure for real-time monitoring of the output power of a linearly polarized laser according to this utility model.

[0013] Figure 2 This is a perspective view of the device for real-time monitoring of the output power of a linearly polarized laser according to this invention.

[0014] Figure 3 This is a schematic diagram of the purification component of this utility model;

[0015] Figure 4 This is a bottom view of the purification component of this utility model;

[0016] Figure 5 This is a schematic diagram of the power sampling component of this utility model;

[0017] Figure 6 This is a bottom view of the power sampling component of this utility model.

[0018] Figure 7 This is a schematic diagram illustrating the principle of the Brewster polarizer stack of this utility model.

[0019] Figure 8 This invention relates to the variation of reflectivity of different polarization components with incident angle for a Brewster window made of ZnSe material at a wavelength of 10.6 μm in this embodiment of the invention.

[0020] Figure 9 This invention relates to the variation of reflectivity of different polarization components with incident angle for a Brewster window made of quartz glass material at a wavelength of 1064nm in this embodiment of the invention.

[0021] In the diagram, 1 is the carrier, 2 is the purification component, 201 is the optical adjustment frame A, 202 is the Brewster polarizer stack, 203 is the support A, 204 is the channel A, 205 is the lens mount A, 206 is the Brewster window A, 207 is the reflection opening A, 3 is the power sampling component, 301 is the optical adjustment frame B, 302 is the Brewster window B, 303 is the support B, 304 is the channel B, 305 is the lens mount B, 306 is the reflection opening B, 4 is the residual light collector, 5 is the power detector, and 6 is the incident laser. Detailed implementation method:

[0022] To more clearly illustrate the overall concept of this utility model, a detailed description will be provided below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0024] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "provided with," "set up," "connected," and "connected" should be interpreted broadly. For example, "provided with" and "set up" can refer to fixed installation, detachable installation, or integration; "connected" can refer to direct connection or connection through an intermediate medium; and "connected" in this application mainly refers to the interconnection of air passages. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0026] like Figures 1-2As shown, a device for real-time monitoring of the output power of a linearly polarized laser includes a carrier 1, which can be a shell structure, a box structure, or a plate, depending on the specific application requirements. A purification component 2 and a power sampling component 3 are sequentially spaced along the transmission direction of the incident laser 6 on the carrier 1. The purification component 2 includes an optical adjustment frame A201, on which a Brewster polarizer stack 202 is mounted. A residual light collector 4 is located in the direction of reflection of the incident laser 6 from the Brewster polarizer stack 202. The residual light collector 4 is existing technology and can be directly purchased or customized. The residual light collector 4 is used to absorb the S-polarization component reflected by the Brewster polarizer stack 202. The power sampling component 3 includes an optical adjustment frame B301, on which a Brewster window is mounted. A power detector 5 is provided on the Brewster window 302 in the direction of reflection of the incident laser 6. The mirror surface of the Brewster polarizer stack 202 forms a Brewster angle with the transmission direction of the incident laser 6, thereby filtering out the S-polarization component mixed in the incident laser 6 when the incident laser 6 is incident along the Brewster angle, and improving the purity of the P-polarization component of the incident laser. The angle between the mirror surface of the Brewster window 302 and the transmission direction of the incident laser 6 deviates from the Brewster angle, and is used to reflect part of the incident laser 6, that is, to reflect a specific proportion of the incident laser 6. In practical applications, it usually reflects 1% to 2% (a specific proportion range) of the P-polarization component. The power detector 5 is used to detect the power of the incident laser 6 reflected by the power sampling component 3. The power detector 5 here is existing technology and can be directly purchased or customized. For example, a 10W thermopile laser power meter can be used. By sequentially arranging a purification component 2 and a power sampling component 3 along the transmission direction of the incident laser 6, the purification component 2 allows the P-polarized component of the incident laser 6 to pass through without loss, while most of the S-polarized component is reflected, thereby reducing the S-polarized component in the incident laser and improving the purity of the P-polarized component. Then, the power sampling component 3 reflects a specific proportion of the incident laser 6, and the power of the incident laser 6 is monitored in real time using a power detector 5. This achieves high-precision, low-interference real-time monitoring of the output power of the linearly polarized laser. It is easy to assemble and debug, applicable to various types of linearly polarized lasers, and can accurately and effectively measure the real-time output power of the laser while the laser processing equipment is operating, allowing for timely adjustment of processing parameters to ensure processing quality.

[0027] like Figures 3-4As shown, the optical adjustment frame A201 is equipped with a bracket A203. The bracket A203 has a channel A204 for the incident laser 6 to pass through. The front end of the bracket A203 is mounted on the optical adjustment frame A201, and the rear end is equipped with a lens mounting base A205. Multiple Brewster windows A206 are sequentially arranged on the lens mounting base A205. The Brewster windows A206 are tilted, and the multiple Brewster windows A206 form a Brewster polarizer stack 202. The upper end of the bracket A203 has a reflection opening A207. The optical adjustment frame, also called an optical lens frame or polarizing lens frame, is existing technology and can achieve adjustments in multiple directions (angles). To facilitate the installation and adjustment of the Brewster windows A206, the bracket A203 and lens mounting base A205 are designed, allowing for the installation and adjustment of multiple Brewster windows A206. The lens mounting base A205 is installed on the bracket A via a threaded connection.

[0028] like Figures 5-6 As shown, the optical adjustment frame B301 is equipped with a bracket B303, which has a channel B304 for the incident laser to pass through. The front end of the bracket B303 is mounted on the optical adjustment frame B301, and the rear end is inclinedly equipped with a lens mounting base B305. The lens mounting base B305 has a Brewster window B302, and the upper end of the bracket B303 has a reflection opening B306. The bracket B303 and the lens mounting base B305 are designed to facilitate the reflection of a specific proportion of incident laser 6, and to facilitate angle adjustment and reflection.

[0029] like Figure 7 As shown, the P-polarization direction of the Brewster polarizer stack 202 is parallel to the incident laser 6 on the incident surface of the Brewster polarizer stack 202, and the S-polarization direction is perpendicular to the incident laser 6 on the incident surface of the Brewster polarizer stack 202. The incident surface is the plane containing the laser incident direction and the normal direction of the incident plane when the incident laser 6 is incident on the Brewster polarizer stack 202.

[0030] Instructions for use of the device for real-time monitoring of the output power of a linearly polarized laser:

[0031] S1. The purification component 2 and the power sampling component 3 are sequentially arranged in the transmission direction of the incident laser 6; the residual light collector 4 is arranged in the reflection direction of the incident laser 6 after passing through the Brewster polarizer stack 202; the power detector 5 is arranged in the reflection direction of the incident laser 6 after passing through the power sampling component 3.

[0032] S2. The angle between the Brewster polarizer stack 202 and the incident laser 6 is adjusted to the Brewster angle by the optical adjustment frame A201, that is, the average power of the transmitted light of the incident laser 6 is the maximum and the average power of the reflected light is the minimum.

[0033] S3. Adjust the angle between the Brewster window 302 and the incident laser 6 using the optical adjustment bracket B301 to the Brewster angle, that is, the average power of the transmitted light of the incident laser 6 is the maximum, while the power of the reflected light is 0, and use this as the adjustment reference point.

[0034] S4. Fine-tune the angle of the Brewster window 302 to reflect 1%-2% of the P-polarization component for real-time monitoring, while maintaining the incident laser transmittance >98%, and the power detector monitors the reflected incident laser power in real time.

[0035] Example 1

[0036] When the output wavelength of a CO2 laser is 10.6 μm, ZnSe material is often used to make lenses and windows for CO2 lasers. For example... Figure 8 As shown, under this condition, the Brewster window angle is 67.4°, at which point the reflectivity of the P-polarization component is 0, and the reflectivity of the S-polarization component is 0.497. At this time, the Brewster polarizer stack 202 is composed of four Brewster windows A206 stacked together, with both interfaces of each Brewster window A206 participating in polarization filtering. At this time, the S-polarization component reflectivity of the Brewster polarizer stack 202 is 0.996, which can reflect 99.6% of the S-polarization component of the incident laser.

[0037] Example 2

[0038] When the output wavelength of an Nd:YAG laser is 1064nm, quartz glass is often used as the lens and window material for Nd:YAG lasers. For example... Figure 9 As shown, under this condition, the Brewster window angle is 55.4°, at which point the reflectivity of the P-polarized component is 0, and the reflectivity of the S-polarized component is 0.126. Therefore, the number of Brewster polarizer stacks 202 needs to be increased. When the Brewster polarizer stack 202 is composed of 20 Brewster windows A206 stacked together, 99.5% of the S-polarized component in the incident laser can be reflected.

[0039] By filtering out the S-polarization component mixed in the incident laser 6 using the Brewster polarizer stack assembly 202, the purity of the P-polarization component of the incident laser 6 is improved. This allows a specific proportion of the incident laser reflected by the power sampling assembly 3 to be pure P-polarization components. At this point, the power of the incident laser transmitted through the power sampling assembly 3 is linearly related to the power of the specific proportion of incident laser reflected. Meanwhile, the content of the S-polarization component in the linearly polarized laser may fluctuate continuously with the operating state of the laser resonator. The Brewster window B302 in the power sampling assembly 3 operates near the Brewster angle, at which point the reflectivity of the S-polarization component remains at a high level. If the S-polarization component mixed in the incident laser is not filtered out, a large amount will be reflected to the power detector 5, resulting in a large proportion of S-polarization component in the detected reflected incident beam. The fluctuation of the S-polarization component content within the laser will significantly interfere with the real-time monitoring of the output power of the linearly polarized laser, affecting the monitoring accuracy.

[0040] After the Brewster polarizer stack assembly 202 is adjusted, the ratio between the incident laser power transmitted through the power sampling assembly 3 and the incident laser power reflected by the power sampling assembly 3 is adjusted by rotating the Brewster window B302. Specifically, by rotating the Brewster window B302 of the power sampling assembly 3 around the transmission direction of the incident laser, the transmitted laser power and reflected laser power of the power sampling assembly 3 are detected, so that the average power of the incident laser transmitted light is maximized, while the reflected light power is basically 0. At this time, the Brewster window B302 is strictly at a Brewster angle with the incident laser. By slightly changing the angle of the Brewster window B302, 1%-2% of the P-polarization component is reflected for real-time monitoring, while maintaining the incident laser transmittance >98%.

[0041] For a CO2 laser with an output power of 300W, adjusting the angle between the Brewster window B302 and the incident laser to 72.9° results in a reflectivity of 0.017 for the P-polarized component and a maximum reflected power of 5.1W. For a Nd:YAG laser with an output power of 500W, adjusting the angle between the Brewster window B302 and the incident laser to 63.7° results in a reflectivity of 0.01 for the P-polarized component and a maximum reflected power of 5W.

[0042] The above specific embodiments should not be construed as limiting the scope of protection of this utility model. For those skilled in the art, any alternative improvements or modifications made to the embodiments of this utility model shall fall within the scope of protection of this utility model.

[0043] Any aspects of this utility model not described in detail are known to those skilled in the art.

Claims

1. A device for real-time monitoring of the output power of a linearly polarized laser, characterized in that, The system includes a carrier on which purification components and power sampling components are sequentially spaced along the incident laser transmission direction. The purification components include an optical adjustment frame A with a Brewster polarizer stack and a residual light collector positioned in the direction of reflection of the incident laser through the Brewster polarizer stack. The power sampling components include an optical adjustment frame B with a Brewster window and a power detector positioned in the direction of reflection of the incident laser through the Brewster window. The angle between the mirror surface of the Brewster polarizer stack and the incident laser transmission direction is a Brewster angle, while the angle between the mirror surface of the Brewster window and the incident laser transmission direction deviates from the Brewster angle, serving to reflect a portion of the incident laser. The power detector is used to detect the incident laser power reflected by the power sampling components.

2. The device for real-time monitoring of the output power of a linearly polarized laser according to claim 1, characterized in that, The optical adjustment frame A is provided with a bracket A, and the bracket A is provided with a channel A for the incident laser to pass through. The front end of the bracket A is mounted on the optical adjustment frame A, and the rear end is provided with a lens mounting seat A. Multiple Brewster windows A are arranged sequentially on the lens mounting seat A. The Brewster windows A are inclined and the multiple Brewster windows A form a Brewster polarizer stack. The upper end of the bracket A is provided with a reflection opening A.

3. The device for real-time monitoring of the output power of a linearly polarized laser according to claim 1 or 2, characterized in that, The optical adjustment frame B is provided with a bracket B, which has a channel B for the incident laser to pass through. The front end of the bracket B is mounted on the optical adjustment frame B, and the rear end is inclinedly provided with a lens mounting seat B. The lens mounting seat B is provided with a Brewster window B, and the upper end of the bracket B is provided with a reflection opening B.

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