CN103017659B - Swash combiner and launch the small potential difference of light path detection system synchronous with angular difference - Google Patents

Abstract

The synchronous detection system for the small position difference and angular difference of the laser beam combining and emitting optical path belongs to the field of photoelectric detection. At the same time, it solves the disadvantage that the current single-point near-field laser angular displacement detection method cannot effectively distinguish the small angular displacement between the laser beams, so it needs to be verified by a certain far-field calibration method. The invention adopts a single detector and two distance point detection method to realize the separation of the angular difference and the potential difference between the laser beams in the laser beam combining system under laboratory conditions, so as to use this precise measurement value to perform high-precision beam combining laser interior decoration. This solution can simplify the detection method, improve the efficiency of detection and adjustment, and reduce the difficulty of installation and adjustment. <!--1-->

Description

Synchronous detection system for small position difference and angle difference of laser beam combining emission optical path

technical field

The invention belongs to the field of photoelectric detection, and in particular relates to a synchronous detection system for the small position difference and angle difference in the assembly and adjustment of each laser in the laser beam combining system and the assembly and adjustment of each device in the beam combining laser light path.

Background technique

Combining multiple laser beams by means of reflection or transmission is a common way of use in the current laser application field. There are two common beam combining technologies. One is to increase the total power of laser modules with the same wavelength and the same power through beam combining technology. The other is to combine the lasers output by lasers with different wavelengths, different powers, and even different divergence angles into one beam for comprehensive application. Regardless of the application form, it is necessary to detect the relative deviation of each laser beam through certain means when performing beam combining and high-precision adjustment. Due to the straight-line transmission characteristics of the beam, if there is a slight position difference between the laser beams output by each optical device in the beam combining laser, the laser beams at the short-range position within a few meters of the laser emission and at the remote position tens of kilometers away will be different. The position of the laser beam spot caused by the position deviation between them will remain unchanged. However, if there is a small angle difference between the laser beams output by each laser in the combined laser beam at the exit position, the laser spot position deviation caused by the angle difference between the laser beams will be enlarged when the laser beam is irradiated tens of kilometers away. The spot position difference caused by angular deviation is proportional to the propagation distance of the beam. During the installation and adjustment of the laser beam combining system, it is necessary to reduce the angle deviation between different laser beams, and the small position difference between the laser beams does not need to be adjusted because there is no effect of amplification with the increase of propagation distance. In order to improve the versatility of the present invention, the present invention will be described by taking laser beam combining of lasers in different wavelength bands as an application background. The traditional laser beam combination method is to detect the angle difference of the laser beam through long-distance real light calibration. The advantage of this method is that the effect is direct, because the small position difference of the combined laser beam at the exit position will not decrease The difference in the position of the spot caused by the angle difference of the laser beam at the far field is much larger than that formed by the position difference of the original laser beam. The laser position deviation is all caused by the angle deviation of the laser beam. However, this primitive detection method requires a lot of manpower and material resources to cooperate, and the efficiency is very low. Therefore, there are currently some detection methods that use laser detectors to detect the position of the laser beam. The method commonly used in these methods is to measure the angle difference of the laser beam by means of close-range laser beam imaging detection at the exit of the beam combining laser, but this The main problem of this short-distance single-point measurement method is that it cannot distinguish the small position difference and angle difference between the laser beams in the combined laser beam. Due to the close-range position detection of the light outlet of the system, the angle difference and position difference between the laser beams are detected, and the position difference of the spot caused by the angle difference between the laser beams with a short optical path is very small (beam combination cannot be ignored like the long-distance real light calibration detection method) The original position difference between the lasers), the laser beam irradiation position deviation measured in this way mixes the position difference and the angle difference, and cannot be effectively distinguished. After finely adjusting the original angle difference of the laser beam converted from the laser beam spot position difference obtained by this detection method, the laser beam may still have a large spot position difference at a distance of tens of kilometers (regardless of the laser beam original angle difference). When the position difference of the laser spot caused by the position difference). Therefore, the scheme of using this short-distance single-point detection method to detect the beam angle and adjust it based on this method often needs to assist a certain long-distance real light calibration for verification. This detection method can simplify the installation and adjustment of the multi-laser beam combining optical path to a certain extent, but it cannot completely replace the traditional real light calibration detection scheme, so the above detection method needs to be improved.

Contents of the invention

The purpose of the present invention is to propose a method for synchronous detection of the small position difference and angle difference between the laser beams emitted by different lasers in the laser beam combining emission path by two-point detection at a short distance (at the exit position of the combined laser beam) The scheme can effectively distinguish the small position difference and the small angle difference between the original laser beams, so as to eliminate the influence of the laser beam spot position difference caused by the original position difference of the laser beam during the precise assembly process of the system, and solve the shortcomings existing in the existing detection technology .

Synchronous detection system for small position difference and angular difference of laser beam combining and emitting optical path, including: beam combining laser, laser beam shaping mirror group, attenuating mirror group, beam splitter, far-field laser beam, near-field laser beam, first reflector, The second reflector, the third reflector, the fourth reflector, the reflective mirror, the beam splitter mirror group, the laser detector and the installation housing; the combined laser beam passes through the laser beam combined and shaped mirror group, and the beam is shaped into a small spot collimation The light beam, through the rotation of the attenuating sheet lens group, selects the attenuating sheet with a suitable attenuation ratio for power attenuation in real time according to the wavelength band and power density of the outgoing laser. The laser beam is divided into a near-field laser beam and a far-field laser through a semi-reflective and semi-transparent beam splitter Two beams, the near-field laser beam directly enters the laser detector through the beam splitter mirror group and the reflective transmission mirror, while the far-field laser beam passes through the first reflector, the second reflector, the third reflector, and the fourth reflector After the reflection of the mirror and the reflective and transmissive mirror, it is combined with the near-field laser in form to form a beam and then enters the laser detector.

The beneficial effects of the present invention are: compared with the prior art, the present invention adopts a short-distance two-point detection method to determine the small position difference and small angle difference of each laser beam in the combined laser beam. The combined laser beam 1 is divided into two laser beams in the far field 5 and the near field 6 through the beam splitter 4 , and then the two laser beams are incident on the same laser detector 13 by means of beam combining. The invention greatly reduces the volume of the system, and at the same time, using a single laser detector for detection can greatly reduce the cost and measurement error, and improve the detection accuracy. This short-distance two-point measurement scheme can determine whether there is a position between the laser beams by comparing the laser spot position map formed by each beam of laser irradiation at the near-field position with the laser spot position map formed by each beam of laser irradiation at the far-field position. At the same time, it can be calculated and inverted to obtain the position and angle difference between the laser beams. In the precision adjustment, the precise adjustment is only performed according to the angle difference, so that the better adjustment results obtained under short-distance conditions due to the elimination of the influence of the original laser position difference will still be better after long-distance amplification. Therefore, this detection scheme can completely replace the traditional complex far-field real cursor calibration detection method, and at the same time, it can make up for the inability to effectively distinguish the position difference and angle difference of each laser beam in the short-range single-point beam combining laser detection. Compared with the traditional long-distance real light calibration detection method, this detection method can greatly reduce the cost, reduce the consumption of manpower and material resources, and improve the efficiency. Compared with the single-point combined laser close-range detection scheme, this detection method can detect the small angle difference and position difference of each laser beam at one time, which solves the need for external field real cursor calibration verification under the single-point detection method, and the verification In the end, if there is a deviation, further adjustments and repeated verifications are required. This two-point detection and adjustment scheme can be completely carried out in the laboratory, which greatly facilitates the precise assembly and adjustment operation before the equipment leaves the factory. This solution adopts a common interface and has a focusing function, which can adapt to the precise detection of beam combination accuracy and optical path transmission accuracy of small and medium power beam combination photoelectric systems.

Description of drawings

Fig. 1 is a schematic diagram of overall optical path transmission in the present invention;

Fig. 2 is the sectional view of overall structural system among the present invention;

Fig. 3 is the structure schematic diagram of attenuation lens group in the present invention;

Fig. 4 is a schematic diagram of the structure of the beam splitting mirror group in the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to accompanying drawing 1, accompanying drawing 2, accompanying drawing 3 and accompanying drawing 4, the synchronous detection system of the micro-phase difference and angular difference of the laser beam combining and emitting optical path of the present invention comprises: laser beam 1, shaping mirror group 2, attenuating sheet mirror group 3 , beam splitter 4, first mirror 7, second mirror 8, third mirror 9, fourth mirror 10, reflection and transmission mirror 11, beam splitter mirror group 12, laser detector 13 and installation housing 14. The beam combining laser 1 passes through the laser beam combining and shaping mirror group 2, and the beam is shaped into a small spot collimated beam. Through the rotation of the attenuating lens group 3, the attenuating film corresponding to the attenuation factor is selected in real time according to the wavelength band and power density of the outgoing laser to adjust the power. Attenuation, the laser beam is divided into two beams, the near-field laser beam 6 and the far-field laser beam 5, through the semi-reflective and semi-transparent beam splitter 4, and the near-field laser beam 6 is directly incident on the laser detector through the beam splitter mirror group 12 and the reflective and transmissive mirror 11 13, the far-field laser beam 5 is combined with the near-field laser beam 6 after being reflected by the first reflector 7, the second reflector 8, the third reflector 9, the fourth reflector 10 and the reflection-transmitting mirror 11 The beam then enters the laser detector 13. Since the greater the optical path difference between the far-field laser beam and the near-field laser beam, the greater the relative deviation of the spot position formed by the irradiation of each laser beam on the far and near images after detection, in order to effectively amplify the The original angle difference and the potential difference, the far-field laser beam 5 enters the laser detector 13 after multiple reflections. During this process, the rotation of the beam splitter mirror group 12 can be used to shield the far-field laser beam 5 when the near-field laser beam 6 is incident or to shield the near-field laser beam 6 when the far-field laser beam 5 is incident.

The specific implementation process is as follows (infrared short, medium, and long-wavelength three-light combined beams are used as an example to illustrate): firstly, the detection system described in the present invention is precisely adjusted with 532nm laser light as the indicator light, when the 532nm laser is vertically incident on the system laser shaping Mirror group, adjust the reflectors in the system to make the laser beam incident in the form of near-field beam and far-field beam incident on the detector as a spot, and adjust each sub-system to meet the requirements of the system. Then erect the packaged detection system to the position of the light outlet of the three-light combining system. Three beams of infrared short-, medium-, and long-wavelength lasers are emitted respectively, and the near-field laser of each laser beam passes through the optical path through the rotation of the beam splitter mirror group 12 to block the far-field laser, so that three wavebands will be formed on the laser detector. Points of the spot position of the laser beam, record the laser spot image with the positions of these three points, and define this image as the near-field laser spot position map. Then emit three laser beams of infrared short, medium, and long-wave bands respectively, and the far-field laser of each laser beam passes through the optical path to block the near-field laser through the rotation of the beam splitter mirror group 12, so that three laser beams will be formed on the laser detector. The spot position point of the laser beam in the wavelength band, record the laser spot image with the positions of these three points, and define this image as the far-field laser spot position map. In this process, if the short, medium, and long-band lasers have their own divergence angles and laser power densities, it is necessary to realize that each laser beam is a small spot through the focusing movement of the laser beam shaping mirror group 2 during the laser emission process. To collimate the laser, select the corresponding attenuation sheets in the attenuation sheet lens group 3 at the same time. In this way, the first round of laser beam angle and position deviation detection is completed. Then compare the relative deviation of the spot positions formed by each laser band in the far-field and near-field positions on the near-field laser spot position map and the far-field laser spot position map, and the spot positions formed between each laser band in the far-field and near-field positions Relative deviation can determine whether there is original angular or positional deviation in the three-beam combining system. The original angle difference and position difference between the beams in the three-beam combining system can be accurately calculated through the deviation value of the spot position output by the laser detector and the optical path length of each laser beam in the three-beam combining system and the detection system. Finally, according to the detected value, the position of each laser in the three-light system or the position of each mirror group during the optical path transmission process is precisely adjusted. The above-mentioned real-time detection is carried out during the assembly and adjustment process, and finally the beam combining accuracy of the laser beams of the three-beam combining system meets the requirements for use.

The laser beam shaping mirror group 2 is composed of a plurality of mirrors arranged in front and back. The focal length adjustment of the system is realized through the fine-tuning movement of some lenses in the system, and the laser beam with a divergence angle within a certain range is shaped into a small spot collimation. Parallel light, so as to compress the spot size that is finally irradiated on the detector CCD, and then effectively distinguish the relative position of each laser beam;

The attenuation sheet lens group 3 includes: a first attenuation sheet 3-1, a second attenuation sheet 3-2, a third attenuation sheet 3-3, a fourth attenuation sheet 3-4, a large gear plate 3-5, a small Gear shaft 3-6, torque motor 3-7, encoder 3-8, base 3-9, torque motor 3-7 are installed in the center of large gear plate 3-5, large gear plate 3-5 outer edge and pinion The outer edge of the shaft 3-6 is meshed, the pinion shaft 3-6 is coaxially installed with the angle measuring encoder 3-8, the first attenuation plate 3-1, the second attenuation plate 3-2, the third attenuation plate 3-3, The fourth attenuator 3-4 adopts different sensitive bands and attenuation magnifications respectively, and is evenly distributed on the large gear plate 3-5, and the large gear plate 3-5 and the pinion shaft 3-6 are installed on the base 3-9 in parallel. On the same side, and achieve mutual meshing, the torque motor 3-7 is coaxially installed with the large gear plate 3-5, and fixed on the other side of the base 3-9, while the encoder 3-8 is coaxially installed with the pinion shaft , and fixed on the base 3-9 on the same side as the torque motor;

The large gear plate 3-5 is driven to rotate through the torque motor 3-7 installed in the center of the gear plate, and the attenuation plate corresponding to the attenuation magnification and sensitive waveband is aligned with the optical axis as required. In this process, the angle measurement encoder 3-8 on the pinion shaft meshing with the large gear plate 3-5 is used to feedback the position of the large gear plate 3-5, so as to ensure that the attenuation plate can still be used after many times of use of the system. Accurate alignment of the optical axis, the system adopts the format of placing the torque motor 3-7 and the angle measuring encoder 3-8 parallel and radially;

The semi-reflective and semi-transparent beam splitter 4 is coated with a laser anti-reflection film and a high-reflection film at the laser incident surface, and the coating system takes into account the short, medium and long infrared laser bands used in the current mainstream beam combining system;

The first reflector 7, the second reflector 8, the third reflector 9, and the fourth reflector 10 are all coated with high-reflection films that take into account multiple laser bands, and the area of the reflectors must be sufficient to ensure that when the incident laser light is relative to the central axis of the optical path When there is a small angle difference or position difference, the beam can also shine on the mirror;

The beam splitting mirror group 12 includes: a disc 12-1, a first through hole 12-2, a second through hole 12-3, a third through hole 12-4, a motor 12-5, and an encoder 12-6 , where the motor 12-5 and the encoder 12-6 are respectively installed on both sides of the disc 12-1, and these three parts are installed coaxially, and the disc 12-1 is directly installed on the side of the motor 12-5 to save space. On the rotor, the stator of the motor 12-5 and the fixed part of the encoder 12-6 are all installed on the installation shell 14. The system adopts a disc structure with three through holes distributed around its periphery, and the size of the through holes can ensure that the laser beam can pass through completely. When the motor 12-5 rotates to align the first through hole 12-2 with the near-field laser beam 6, it can ensure that only the near-field laser beam 6 passes through and the far-field laser beam 5 is blocked. When the hole 12-2 is aligned with the far-field laser beam 5, it can ensure that the far-field laser beam 5 passes through and blocks the near-field laser beam 6. When the second through hole 12-3 and the third through hole 12-4 are respectively aligned with the far-field laser beam The field laser beam 5 and the near-field laser beam 6 can ensure that the two laser beams pass through at the same time, and when the position of the disc 12-1 without a through hole is aligned with the far-field laser beam 5 and the near-field laser beam 6, the system can simultaneously block Propagation of near and far laser beams;

The reflective transmissive mirror 11 is coated with an anti-reflection film on the incident surface of the near-field laser beam 6, and coated with a high-reflection film on the incident surface of the far-field laser beam 5;

The detection target surface of the laser detector 13 can effectively receive and detect the position of the laser beam with a certain angular difference or potential difference;

The installation shell 14 adopts a lightweight design integrated casting and molding technical solution, and adopts a universal port design at the incident end of the laser beam to be suitable for different laser emission ports of various photoelectric systems.

During the assembly and adjustment of the first reflector 7, the second reflector 8, the third reflector 9, and the fourth reflector 10, a small-spot single-band laser beam can be used as an indicating laser for high-precision indication. The near-field laser beam 6 and the far-field laser beam 5 incident on the laser detector 13 are synthesized into one beam through precise adjustment. The installation and adjustment of this system is carried out at room temperature, and the precision detection of the combined beam laser after the installation and adjustment is also carried out in this environment, thereby eliminating the random error of the system caused by changes in environmental conditions.

Claims (6)

1. swash combiner and launch the small potential difference of light path detection system synchronous with angular difference, comprise laser beam (1), shaping mirror group (2), attenuator mirror group (3), half-reflection and half-transmission spectroscope (4), first catoptron (7), second catoptron (8), 3rd catoptron (9), 4th catoptron (10), reflection and transmission mirror (11), light beam shunting mirror group (12), laser detector (13) and mounting casing (14), laser beam (1) forms small light spot collimated light beam after shaping mirror group (2), corresponding attenuator is selected with power density by the rotation of attenuator mirror group (3) according to the wave band of the laser beam (1) of outgoing, laser beam (1) is divided near field laser beam (6) and far-field laser bundle (5) by half-reflection and half-transmission spectroscope (4), near field laser beam (6) incides laser detector (13) through light beam shunting mirror group (12) and reflection and transmission mirror (11), and far-field laser bundle (5) is by the first catoptron (7), second catoptron (8), 3rd catoptron (9), 4th catoptron (10) and reflection and transmission mirror (11) reflection after and near field laser beam (6) synthesize a branch of after be incident in laser detector (13).

2. swash combiner according to claim 1 and launch the small potential difference of light path detection system synchronous with angular difference, it is characterized in that, described attenuator mirror group (3) comprising: the first attenuator (3-1), second attenuator (3-2), 3rd attenuator (3-3), 4th attenuator (3-4), canine tooth wheel disc (3-5), pinion shaft (3-6), torque motor (3-7), measurement of angle scrambler (3-8) and base (3-9), canine tooth wheel disc (3-5) outer rim engages with pinion shaft (3-6) outer rim, pinion shaft (3-6) and measurement of angle scrambler (3-8) are coaxially installed, first attenuator (3-1), second attenuator (3-2), 3rd attenuator (3-3), 4th attenuator (3-4) is evenly distributed on canine tooth wheel disc (3-5), canine tooth wheel disc (3-5) and pinion shaft (3-6) are installed in parallel in the same side of base (3-9), torque motor (3-7) and canine tooth wheel disc (3-5) are coaxially installed, and be fixed on the opposite side of base (3-9), measurement of angle scrambler (3-8) and torque motor are arranged on the same side of base (3-9).

3. swash combiner according to claim 1 and launch the small potential difference of light path detection system synchronous with angular difference, it is characterized in that, half-reflection and half-transmission spectroscope (4) is at laser entrance face place plating laser anti-reflection film and highly reflecting films.

4. swash combiner according to claim 1 and launch the small potential difference of light path detection system synchronous with angular difference, it is characterized in that, the first catoptron (7), the second catoptron (8), the 3rd catoptron (9) and the 4th catoptron (10) all plate the highly reflecting films of many laser wavelengths.

5. swash combiner according to claim 1 and launch the small potential difference of light path detection system synchronous with angular difference, it is characterized in that, described light beam shunting mirror group (12) comprises disk (12-1), first through hole (12-2), second through hole (12-3), third through-hole (12-4), motor (12-5) and scrambler (12-6), scrambler (12-6) is installed in disk (12-1) side, opposite side mounted motor (12-5), disk (12-1), scrambler (12-6) and motor (12-5) three coaxially install, disk (12-1) is arranged on the rotor of motor (12-5), the stator of motor (12-5) and the fixed part of scrambler (12-6) are installed on mounting casing (14), ensure only to block far-field laser bundle (5) by near field laser beam (6) when motor (12-5) rotates and enables the first through hole (12-2) aim near field laser beam (6), ensure that when rotating and making the first through hole (12-2) aim at far-field laser bundle (5) to another angle far-field laser bundle (5) passes through and blocks near field laser beam (6), ensure that two laser passes through simultaneously when enabling the second through hole (12-3) and third through-hole (12-4) aim at far-field laser bundle (5) and near field laser beam (6) respectively, and when enabling disk (12-1) block the propagation of far and near field laser beam without system during lead to the hole site aligning far-field laser bundle (5) and near field laser beam (6) simultaneously.

6. swash combiner according to claim 1 and launch the small potential difference of light path detection system synchronous with angular difference, it is characterized in that, reflection and transmission mirror (11), near field laser beam (6) plane of incidence plating anti-reflection film, plates highly reflecting films at far-field laser bundle (5) plane of incidence.