CN201724738U - High Power Laser Near Field Tester - Google Patents

Abstract

The utility model provides a high-power laser near-field tester. In the optical path of the tester, the high-power laser beam sequentially passes through the first lens, the pinhole filter, the second lens and the attenuator, and enters the CCD. The first lens and the second lens form a large-diameter beam reduction system. The collimated light after the beam reduction passes through the attenuator, and the measured beam is imaged on the CCD through the beam reduction system and the attenuator. A pinhole filter is provided on the common focus. The attenuator is composed of a fixed attenuation plate and a variable attenuation plate. The first incident surface of the combination of the fixed attenuation plate and the variable attenuation plate is coated with a reflective film with different reflectivity, and the second incident surface is coated with an anti-reflection film. Various attenuation magnifications can be obtained by using a combination of several fixed attenuation plates and variable attenuation plates. The signal of the measured laser passing through the attenuator is within the linear response range of the CCD. The utility model has the advantages of simple structure, convenient adjustment and high near-field test precision.

Description

High Power Laser Near Field Tester

technical field

The utility model belongs to the field of high-power laser parameter testing, and mainly relates to a high-power laser near-field tester. the

Background technique

For high-power laser devices, the near-field distribution refers to the optical energy density distribution on the cross-section of the laser beam at a specific spatial position. Due to the nonlinear effect of high-power laser devices, the near-field is strongly modulated. In the near-field position, the risk of damage is relatively high, which greatly limits the load capacity of the device. The purpose of near-field testing is to ensure beam alignment, evaluate beam spatial quality, monitor damage to laser optical components, and provide a basis for the operation and maintenance of high-power laser devices through near-field testing. the

Contents of the invention

The utility model provides a high-power laser near-field tester. the

The technical solution adopted by the utility model to solve the technical problem is: in the optical path of the high-power laser near-field tester of the utility model, the high-power laser beam passes through the first lens, the pinhole filter, the second lens and the attenuator in sequence, incident on the CCD. The first lens and the second lens form a large-diameter beam reduction system. The collimated light after the beam reduction passes through the attenuator, and the measured beam is imaged on the CCD through the beam reduction system and the attenuator. A small hole filter is set on the common focus. The attenuator is composed of the first fixed attenuation plate, the second fixed attenuation plate, the third fixed attenuation plate, the fourth fixed attenuation plate and the variable attenuation plate, the first fixed attenuation plate, the second fixed attenuation plate, the third fixed attenuation plate 1. The fourth fixed attenuation plate and the first incident surface of the variable attenuation plate are coated with reflective films with different reflectivity, and the second incident surface is coated with anti-reflection film. the

The beneficial effect of the utility model is that the high-power attenuation of the measured high-power laser is transmitted through the fixed attenuation plate and the variable attenuation plate with high attenuation magnification, and near-field distribution without distortion can be obtained. The utility model has the advantages of simple structure, convenient adjustment and high near-field test precision. the

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described. the

Figure 1 is a schematic diagram of the optical path structure of the high-power laser near-field tester of the present invention. the

Fig. 2 is a schematic diagram of the optical structure of the attenuator in the utility model. the

In the figure 1. First lens 2. Pinhole filter 3. Second lens 4. Attenuator 5. CCD 21. First fixed attenuation plate 22. Second fixed attenuation plate 23. Third fixed attenuation plate 24. Fourth Fixed attenuation plate 25. Variable attenuation sheet. the

Detailed ways

Figure 1 is a schematic diagram of the optical path structure of the high-power laser near-field tester of the present invention. As shown in Figure 1, a high-power laser with a wavelength of 1.054 μm and a beam diameter of 70mm×70mm passes through the first lens 1, the pinhole filter 2, the second lens 3 and the attenuator 4 in sequence, and enters the CCD5. The first lens 1 and the second lens 3 to form a large-diameter beam reduction system. In order to prevent the ambient stray light from entering the test system and affecting the contrast and clarity of the image, a small hole filter 2 is set on the common focus of the first lens 1 and the second lens 3. The collimated light of 10mm×10mm after beam reduction passes through the attenuator 4, and the measured beam is imaged on the CCD5 through the beam reduction system and the attenuator 4 to obtain the near-field energy distribution. In Fig. 2, the attenuator 4 is made up of the first fixed attenuation plate 21, the second fixed attenuation plate 22, the third fixed attenuation plate 23, the fourth fixed attenuation plate 24 and the variable attenuation sheet 25, the first fixed attenuation plate 21, The second fixed attenuation plate 22 , the third fixed attenuation plate 23 , and the fourth fixed attenuation plate 24 perform large-magnification attenuation, and the variable attenuation sheet 25 is used for small-magnification attenuation. The first incident surface of the first fixed attenuation flat plate 21, the second fixed attenuation flat plate 22, the third fixed attenuation flat plate 23, the fourth fixed attenuation flat plate 24 and the variable attenuation sheet 25 is plated with reflective films of different reflectivity as required, and the second The incident surface is coated with anti-reflection coating. The incident beam is transmitted and attenuated by the attenuating plate and the variable attenuating plate, and various attenuation magnifications are obtained by using different attenuating plates and attenuating plate combinations. the

In order to ensure the imaging relationship, a beam reduction system with a real focus is used to reduce the beam from 70mm×70mm to 10mm×10mm. Due to the large beam reduction ratio, the conjugate distance of the single-lens contraction system composed of two lenses is large, and the instrument structure is huge. The combined lens structure is used, and the reflection images on the surfaces of the combined lens cannot be focused on other optical elements. the

For the measured high-power laser, in order to make the signal entering the detector CCD5 not saturated, it is necessary to insert an attenuator 4 with a high attenuation factor in the optical path. The wave aberration is as small as possible. If the attenuator 4 is placed in front of the first lens 1, a large-diameter attenuation plate is required, which will increase the cost. If it is placed in the converging optical path, a large additional aberration will be generated, so the attenuator 4 is placed after the narrowing beam in parallel light. The attenuator 4 is composed of a first fixed attenuation plate 21 , a second fixed attenuation plate 22 , a third fixed attenuation plate 23 , a fourth fixed attenuation plate 24 and a variable attenuation plate 25 . The first fixed attenuation plate 21 , the second fixed attenuation plate 22 , the third fixed attenuation plate 23 , and the fourth fixed attenuation plate 24 are used for large-magnification attenuation. In order to reduce the interference formed by the light beams between the first fixed attenuation plate 21, the second fixed attenuation plate 22, the third fixed attenuation plate 23, and the fourth fixed attenuation plate 24, the attenuation plate is placed at 45 ^° , and the fixed attenuation plate is formed by Composed of K9 glass coating, the first incident surface is coated with high-reflection film, the reflectivity is 99% when placed at 45 degrees, the second incident surface is coated with anti-reflection film, the reflectivity is less than 0.5% when placed at 45 degrees, and the two sides of the fixed attenuation plate The flatness is λ/10; the fixed attenuation plate is fixed on its own mobile bracket, which can be manually or automatically moved into or out of the optical path, and has an automatic positioning function. The variable attenuation plate 25 placed behind the fixed attenuation plate is used for small-magnification attenuation. For the convenience of adjustment, it is placed at 0 ^0. There are six variable attenuation plates 25, each of which is composed of K9 glass coating, and the first incident surface is coated with reflection film, the reflectivity is 90%, 80%, 60%, 50%, 20%, 10%, respectively, the second incident surface is coated with anti-reflection film, the reflectivity is less than 0.5%, the planes of the two sides of the variable attenuation sheet 25 The degree is λ/10. The variable attenuation plate 25 is placed on the rotary arm type turntable. The turntable can be rotated manually and has the functions of positioning and identification. By turning the turntable, six different attenuation values can be obtained conveniently. The adjustment method of the variable attenuation plate 25 can also be adjusted by translation Realize the conversion of six attenuation slices.

In order to avoid multi-beam interference in the first fixed attenuation plate 21, the second fixed attenuation plate 22, the third fixed attenuation plate 23, the fourth fixed attenuation plate 24 and the variable attenuation plate 25, the attenuation plate can be processed to have a certain The splitting board with a wedge angle, such as a wedge angle of 10 degrees; the inner wall of the attenuator tube is all blackened to absorb stray light. The CCD5 can be adjusted two-dimensionally in the horizontal plane. By moving the CCD5, the surface of the measured object can be imaged on the CCD5. The CCD5 has a real-time acquisition function. The inner wall of the entire instrument is made of absorbing glass, and all light-shielding surfaces are painted with black matte paint to absorb scattered light. And reflected light, improve the signal-to-noise ratio of images collected by CCD5. the

Claims (3)

1. high power laser light near-field test instrument, it is characterized in that: high-power laser beams through first lens (1), small filter (2), second lens (3) and attenuator (4), incides CCD(5 successively); First lens (1) and second lens (3) are formed the heavy caliber beam system that contracts, the collimated light that contracts after restrainting passes through attenuator (4), tested light beam through contract beam system and attenuator (4) imaging in CCD(5) on, on the public focus of first lens (1) and second lens (3), be provided with a small filter (2), attenuator (4) is by the first fixed attenuation flat board (21), the second fixed attenuation flat board (22), the 3rd fixed attenuation flat board (23), the 4th fixed attenuation flat board (24) and variable attenuation sheet (25) are formed, the first fixed attenuation flat board (21), the second fixed attenuation flat board (22), the 3rd fixed attenuation flat board (23), the reflectance coating of the 4th fixed attenuation flat board (24) and variable attenuation sheet (25) first incidence surfaces plating different reflectivity, second incidence surface plating antireflective film.

2. high power laser light near-field test instrument according to claim 1, it is characterized in that: the described first fixed attenuation flat board (21), the second fixed attenuation flat board (22), the 3rd fixed attenuation flat board (23), the 4th fixed attenuation flat board (24) carry out the transmission decay to incident beam, and 45 degree are positioned in the light path; The dull and stereotyped peace of each fixed attenuation frame is on traversing carriage separately.

3. high power laser light near-field test instrument according to claim 1 is characterized in that: the described first fixed attenuation flat board (21), the second fixed attenuation flat board (22), the 3rd fixed attenuation flat board (23), the 4th fixed attenuation flat board (24) and variable attenuation sheet (25) are for having the plate of splitting of carving the angle.

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