RU2793612C1 - Method for forming and directing laser radiation of emitters with optical fibre outputs to a target - Google Patents

Abstract

FIELD: optoelectronic instrumentation.

SUBSTANCE: invention relates to laser systems for formation and guidance of laser radiation at remote targets. The method of formation and guidance of laser radiation from emitters with fibre optic leads to a target differs from the known one in that for each emitter with a fibre optic lead, glare reflected from the target is received, an image is built and the coordinates of the target are measured in the precision pointing receiving unit, precise aiming and focusing of radiation on the target and formation of a given radiation pattern. In this case, the reception of the glare reflected from the target, formation of radiation and formation of a given radiation pattern for each emitter is carried out by a non-axial circular zone of a long-focus collimator common for all emitters, in the focal plane of which the centres of the ends of the cores of the fibre optic leads inclined to the axis of the long-focus collimator are located. The probing radiation reflected from the target and the radiation induced on the target of each emitter with a fibre-optic output are separated by a beam-splitting element.

EFFECT: formation of the diffraction quality of the radiation, an increase in the accuracy of pointing, an increase in the radiation density at the target.

1 cl, 1 dwg

Description

The invention relates to optoelectronic instrumentation and can be used in the development of laser systems in terms of the formation and guidance of laser radiation at remote targets.

A known method of generating and pointing laser radiation of n-emitters at a target [1], including the formation of probing radiation and irradiation of the area of the intended location of the target, search and rough guidance of the probing radiation on the target, receiving a flare reflected from the target and building an image of the target, precise guidance, formation of the output beam of n-emitters and focusing of laser radiation of n-emitters on the target. This method does not allow the formation of a beam of diffraction quality at the output, even when using single-mode fiber lasers. Also, the disadvantages include:

- low radiation density on the target due to the lack of a formation system for each emitter; focusing and aiming the total radiation of n-emitters at the target by a common telescopic formation system;

- degradation of the radiation quality of each emitter when passing through a beam-splitting element mounted at an angle to the optical axis;

- large radiation loads on the eyepiece of the telescope due to its close location to the end of the radiating body of the emitter;

- cumbersome design, tk. the telescope combines all emitters and the output aperture of the telescope is ~∅ 0.5-1 m;

- the difficulty of replacing individual laser modules when they fail or their power drops.

There is a known method of forming and pointing laser radiation at a target [2], including the formation of laser radiation from 4 emitters with short-focus collimators, pointing each emitter at the target with rotary flat mirrors installed behind each collimator, compensating the focal length of the collimator caused by thermal effects in the forming optics of the collimator , longitudinal movement of the eyepiece of the two-fold beam expander. When using this method of forming and pointing radiation at the target, significant disadvantages are: a wide radiation pattern of laser radiation due to the short focus of the collimator ~ 250 mm, low accuracy of pointing each emitter at the target due to the lack of a receiving channel and accurate pointing; low radiation density on the target due to the lack of radiation focusing at a given range and a wide radiation pattern of the emitter.

The closest in technical essence to the proposed method is the method of generating and directing laser radiation from emitters with fiber optic leads to the target [3], including the formation of probing radiation and irradiation of the zone of the intended location of the target, search and rough guidance of the probing radiation on the target, receiving reflected from the target glare and building an image of the target, measuring the coordinates of the detected targets and the distance to them, forming the radiation of each emitter with a short-focus collimator in the form of an aspherical lens, adding the radiation of each emitter by an adder of single laser beams with beam-splitting elements installed at an angle of 45 ° to the optical axis in the form of dichroic plates, formation of the required directivity pattern of the total laser radiation of all emitters in a mirror-lens telescope with an off-axis parabolic mirror objective and a movable aspherical eyepiece lens mounted on a micropositioner of a three-coordinate scanning unit that accurately aims and focuses the total radiation of all emitters on the target. The disadvantages of this method include:

- inefficient formation of the resulting laser beam;

- a large number of optical surfaces in the optical system, the errors of which affect the accuracy of the formed wave front and the accuracy of aiming at the target;

- the complexity and high cost of manufacturing aspherical optics for the collimator and telescopic system, the complexity of adjusting the off-axis parabolic mirror;

- low radiation density on the target due to the focusing and guidance of the total radiation of all emitters on the target by a common telescopic formation system;

- large radiation loads on the collimator and eyepiece of the telescope due to the close location of the optical elements to the end of the radiating body of the emitter;

- additional coordination of the receiving and transmitting channels due to their non-coaxial location relative to each other.

The objective of the invention is the effective formation of the diffraction quality of the radiation, increasing the accuracy of pointing, increasing the radiation density at the target.

The problem is solved by the fact that in the known method of formation and guidance of laser radiation from emitters with fiber optic leads to the target, including search and rough guidance to the target, the formation of probing radiation and irradiation of the zone of the supposed location of the target with it, reception of the flare reflected from the target, imaging and measurement coordinates of the target in the receiving unit of coarse guidance, coarse guidance to the target, reception of the flare reflected from the target, imaging and measurement of target coordinates in the receiver of fine guidance, fine guidance to the target, measurement of the range to the target and focusing of radiation on it, formation of emitter radiation with fiber optic outputs of a given radiation pattern and focusing it on the target, receiving glare reflected from the target, building an image and measuring the coordinates of the target in the receiving unit of fine guidance, precise guidance and focusing of radiation on the target, the formation of a given radiation pattern is performed for each emitter with a fiber optic output, in this case, the reception of the flare reflected from the target, the formation of radiation and the formation of a given radiation pattern for each emitter is carried out by a non-axial circular zone of a long-focus collimator common to all emitters, in the focal plane of which the centers of the ends of the cores of the fiber-optic leads inclined to the axis of the long-focus collimator are located, the probing radiation reflected from the target and the target-directed radiation of each fiber-optic lead emitter is separated by a beam-splitting element.

The figure shows a schematic optical diagram of the implementation of the proposed method, where: 1 - long-focus collimator; 1.1 - non-axial circular zone of the formation system of each emitter; 2 - emitter with fiber optic output; 3 - end of the fiber-optic output core; 4 - scanning device; 5 - receiving unit for precise guidance; 6 - focusing device; 7 - beam-splitting element; 8 - device for probing radiation; 9 - device rough guidance; 10 - receiving block rough guidance; 11 - rangefinder device; 12 - electronic control and processing unit.

The system of formation and guidance of laser radiation emitters on the target using the proposed method includes receiving and transmitting channels.

The receiving channel consists of a long-focus collimator 1, a beam-splitting element 7 and a fine pointing receiving unit 5 and is designed to receive glare reflected from the target and build an image of the target in the fine pointing receiving unit 5. The object plane of the receiving channel is the target plane, the image plane is the sensitive area of the receiving block 5.

The transmitting channel consists of a long-focus collimator 1; beam-splitting element 7. The object plane of the transmitting channel is the plane of the end face of the core 3 of the fiber-optic output of the emitter 2, the image plane is the plane of the target. The transmitting channel is designed to form a given radiation pattern of the laser radiation emitter with a fiber optic output and focus it on the target.

The receiving and transmitting channels are optically separated by a beam splitter 7.

The long-focus collimator 1 is designed to form the radiation of a given radiation pattern of each emitter and is a two or three lens system with standard spherical surfaces. The formation of radiation and the formation of a given radiation pattern for each emitter is carried out by a non-axial circular zone 1.1 of a long-focus collimator 1 common to all emitters. optical surfaces of lenses.

The emitter 2 with a fiber optic output is designed to create laser radiation. The emitters are inclined to the axis of the long-focus collimator, in the focal plane of which the centers of the inclined ends of the cores of the fiber-optic leads 3 are located. At the initial position of the optical length of the long-focus collimator, a beam comes out through it, focused to infinity and focused to a given range when it changes (increases).

The scanning device 4 is intended for precise aiming of laser radiation at the target.

The fine targeting receiving unit 5 is designed to receive glare reflected from the target and build an image of the target on the sensitive area of the receiving unit.

The focusing device 6 is designed to focus the laser radiation on the target.

The beam-splitting element 7 is designed for optical separation of the receiving and transmitting channels.

The probing radiation device 8 is designed to create probing radiation and irradiate the zone of the intended target location with it.

The coarse guidance device 9 can be made in the form of a turntable, on which the devices of the system are placed and is intended for rotation in azimuth and inclination in elevation.

The coarse guidance receiving unit 10 is designed to receive glare reflected from the target and build an image of the target on the sensitive area of the receiving unit.

The rangefinder device 11 is designed to determine the range to the detected targets.

The electronic control and processing unit 12 is designed to control the processes of radiation formation, search for targets, coarse and fine pointing and focusing of radiation on the target, analysis and processing of the obtained images.

The method of formation and guidance of laser radiation emitters with fiber optic output to the target is implemented as follows.

From the electronic control and processing unit 12, a command signal is sent to turn on and operate the coarse guidance device 9 and the coarse guidance receiving unit 10. The terrain is surveyed, the search for targets is carried out by rotating and tilting the turntable of the coarse guidance device 9 in the operating range of angles and the construction of images of the detected targets in the receiving unit of coarse guidance 10. The received information enters the electronic control and processing unit 12 and the analysis and processing of the received images is carried out, the zone of the alleged location of the detected target is determined. To determine the vulnerable spot of the detected target, a command is sent from the electronic control and processing unit 12 to probe this area with probing radiation, and the probing radiation device 8 is turned on.

The radiation of the probing radiation device 8 probes the space of the alleged location of the detected target, is reflected from the target and received by the coarse guidance receiving unit 10. Signals about the location of the detected target from the sensitive area of the coarse guidance receiving unit 10 are sent to the electronic control and processing unit 12, the coordinates of the detected goals. From the electronic control and processing unit 12, a command signal is sent to rough pointing the system at the target. By rotating and tilting the turntable of the coarse guidance device 9, coarse guidance is performed on the target, the target image is brought to the center of the coarse guidance receiving unit 10 with a coarse guidance accuracy equal to or less than the angular field of view of the fine guidance device. The system, with the accuracy of a coarse guidance device, is pointed at a detected target, and the target enters the fine guidance field of view.

Precise targeting is done. The probing radiation reflected from the target is received by the non-axial circular zone 1.1 of the long-focus collimator 1 common to all emitters, passes through the non-axial part of the lenses and the beam-splitting element 7 and builds an image of the target in the plane of the fine targeting receiving unit 5 in the operating range of angles of the field of view of the fine targeting device.

Signals about the location of the detected target are received from the receiving unit of fine guidance 5 to the electronic control and processing unit 12, and the coordinates of the detected target are measured. From the electronic control and processing unit 12, a command signal is sent to turn on the scanning device 4. The system is accurately aimed at the target, the target image is brought to the center of the field of view of the fine guidance receiving unit 5 by scanning. The target is on the axis of the receiving channel.

Since the object plane of the receiving channel is the plane of the target and the plane of the images is the plane of the receiving unit of fine guidance, and the object plane of the transmitting channel is the plane of the end face of the core of the fiber optic output of the emitter, from where a single laser beam comes out and the image plane is the plane of the target, then when the system is precisely aimed at the target and the target image is on the axis of the receiving channel, then the target is also on the axis of the transmitting channel, and the output radiation of each emitter is precisely aimed at the target. And at the same time, the conjugation of each end of the core of the fiber-optic output of the emitter, from where the laser beam comes out, and the target is ensured.

From the electronic control and processing unit 12, a command signal is sent to turn on and operate the range finder device 11. The distance to the target is measured. From the electronic control and processing unit 12, a command signal is sent to turn on the focusing device 6. Each emitter 2 is focused on the target.

From the electronic control and processing unit 12, a control command is given to supply power to each emitter 2. Each emitter begins to generate coherent electromagnetic waves transmitted through its fiber optic output, the end of the core of which 3 is a radiation source, from which a single laser beam comes out.

The output laser radiation of each emitter, coming from the end of the core of the fiber-optic output 3, passes through the beam-splitting element 7, the off-axis part of the spherical lenses 1.1 of the long-focus collimator 1 common for all emitters, forming the radiation of the required radiation pattern close to the diffraction quality, and comes out focused on the target.

The output of each emitter is precisely directed and focused on the target.

In the proposed method for the formation and guidance of laser radiation from emitters with fiber-optic leads to the target, separate implementation for each emitter of precise aiming and focusing of radiation on the target and the use of receiving glare reflected from the target as an optical system, the formation of radiation and the formation of a given radiation pattern for each emitter is non-axial circular a zone of a long-focus collimator common to all emitters of several spherical lenses, in the focal plane of which are located the centers of the ends of the cores of the fiber optic leads inclined to the axis of the long-focus collimator, allow:

- effectively generate diffraction-quality radiation, both of each emitter and the total radiation of all emitters;

- to improve the accuracy of pointing laser radiation at the target due to the formation of the diffraction quality of radiation in each emitter, the use of a non-axial circular zone common to all emitters of a long-focus collimator from several spherical lenses as a radiation formation system for each emitter, a system for forming a given radiation pattern and receiving reflected from the target of glare, precise aiming and focusing of each emitter on the detected target, simplifying alignment and using standard spherical optics;

- increase the radiation density at the target by forming the diffraction quality of the radiation at the output, both of each emitter and the total radiation of all emitters, increasing the accuracy of pointing at the detected target.

Information sources:

1. V.I. Kishko, V.F. Matyukhin. Principles of constructing adaptive repeaters for stratospheric power transmission systems // Avtometriya. 2012. V. 48, No. 2. With. 59-66.

2. Sprangle, Phillip & Ting, A. & Penano, J.R. & Fischer, Richard & Hafizi, Bahman. (2008). Incoherent Combining of High-Power Fiber Lasers for Directed-Energy Applications. 2.25.

3. Patent RU 2663121, published 08/07/2018, bul. No. 22, IPC: G01S 17/88 (2006.01), F41G 3/22 (2006.01) - prototype.

Claims (1)

A method for generating and pointing laser radiation from emitters with fiber optic leads to a target, including searching and coarse aiming at a target, generating probing radiation and irradiating the zone of the intended location of the target with it, receiving a flare reflected from the target, building an image and measuring the target coordinates in the coarse guidance receiving unit, coarse aiming at the target, receiving the flare reflected from the target, building an image and measuring the coordinates of the target in the fine targeting receiving unit, fine targeting, measuring the range to the target and focusing the radiation on it, forming the radiation of emitters with fiber-optic outputs of a given radiation pattern and focusing it on the target, characterized in that the reception of glare reflected from the target, the construction of the image and the measurement of the target coordinates in the receiving unit of fine guidance, the precise guidance and focusing of radiation on the target, the formation of a given radiation pattern are performed for each emitter with a fiber optic output, while receiving the reflected from the target of the flare, the formation of radiation and the formation of a given radiation pattern for each emitter is carried out by a non-axial circular zone of a long-focus collimator common for all emitters, in the focal plane of which there are centers of the ends of the cores of the fiber optic leads inclined to the axis of the long-focus collimator, the probing radiation reflected from the target and induced on the target the radiation of each emitter with a fiber optic output is separated by a beam splitter.

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