CN105352639A - Test system of impulse coupling efficiency of target under the action of laser - Google Patents

Abstract

The present invention proposes a testing system for the coupling efficiency of the laser acting on the target, which consists of a compound pendulum device for placing the target, a movable scale device for detecting the maximum swing angle of the compound pendulum, a detection light source, an oscilloscope, a laser energy adjustment unit, an energy The compound pendulum device is composed of a compound pendulum and a compound pendulum bracket; the movable scale device is composed of a GHz photoelectric sensor, a one-dimensional translation platform and a horizontal slide rail; the photoelectric sensing unit is used to capture the measured target and obtain the impulse under laser irradiation And the maximum swing angle reached by pushing the compound pendulum, and then using the law of energy conservation to obtain the initial impulse of the compound pendulum under laser irradiation, and through the dimensionless processing of the impulse coupling efficiency, the impulse to the target when the laser single pulse energy changes Coupling coefficient change curve. The invention can adapt to the test of the coupling efficiency of the laser acting on the target under the non-friction suspension state of the target, and realizes accurate measurement with GHz dynamic response, large range, large swing angle and high sensitivity.

Description

A testing system for the impulse coupling efficiency of laser on the target

technical field

The invention belongs to the technical field of optical measurement, in particular to a testing system for measuring the impulse coupling efficiency of a laser acting on a target, which can be used for optical testing of the measuring impulse coupling efficiency of a laser acting on space debris, and for research on laser space debris cleaning technology.

Background technique

In the prior art, for the measurement of the impulse coupling efficiency obtained by the target under the action of the laser, the compound pendulum device is used to suspend the target, and the initial velocity or angular velocity of the target under the action of the laser is obtained by high-speed photography technology or beam deflection method, and then the entire compound pendulum The device integrates the velocity of all mass elements to obtain the initial momentum or angular momentum of the system. Another method is to measure the maximum deflection angle that the compound pendulum device can reach after laser action, and then convert the initial momentum of the system through the principle of energy conservation. However, it is difficult to accurately measure the mass distribution of a compound pendulum device, especially for targets with special shapes or complex internal structures, and it is easy to introduce large errors in the determination of the center of mass of the system and the distribution of mass elements. For the application of the measurement of the impulse coupling coefficient obtained by space debris under the action of laser, it faces the problem that the internal structure of the debris target is complex and it is difficult to accurately measure its mass distribution. In addition, due to the limited frame rate of high-speed photography technology, it will cause the maximum swing angle measurement error, which becomes another source of measurement error.

Some scholars also use transient mechanical sensors to directly measure the recoil pressure obtained by the target under the action of laser. However, the measurement accuracy, measurement time resolution and range of this method depend directly on the sensitivity, dynamic response range and range of the pressure sensor. The working principle of piezoelectric components determines that it must exchange for a larger range by losing sensitivity and dynamic response range. For the application of the measurement of the impulse coupling coefficient of space debris under the action of laser, it is necessary to obtain the action laser parameters that maximize the coupling coefficient, that is to say, the pressure sensor needs to have a measurement range of gigapascal level. On the other hand, the laser action source used for space debris removal has a nanosecond (10^-9s) pulse width, and the recoil pressure generated by the action on the surface of the debris target is on the order of microseconds (10^-6s). This requires the pressure sensor to have at least a MHz dynamic response range. Pressure sensors made of common piezoelectric ceramic stacks or piezoelectric films cannot meet the requirements of large range and high response frequency at the same time.

It is also reported that the guide rail method is used, for example, the horizontal double-line support method is used to reduce the friction between the guide rail and the target, so that the measured initial average velocity of the target within a small initial distance is closer to the initial initial velocity obtained under the action of the laser. or use an air cushion guide rail, by approximating the friction force generated by the air film between the target and the guide rail to be constant, and fitting the displacement data of the target at the sequence time to the uniform deceleration linear motion formula to obtain the target under the action of the laser. Initialising speed. However, the disadvantages of using the guide rail method are obvious, especially for the application of the measurement of the impulse coupling coefficient obtained by space debris under the action of laser, because the space debris target is in a frictionless suspension state under the action of laser, any small recoil pressure generated by laser action will achieve effective momentum transfer to the target. Therefore, the error caused by the friction between the guide rail and the target on the measurement of the impulse coupling coefficient cannot be ignored.

Contents of the invention

The purpose of the present invention is to provide a test system for measuring the coupling efficiency of the impulse of the laser on the space debris, which is adapted to the test of the coupling efficiency of the impulse of the laser on the target in the frictionless suspension state by greatly reducing the frictional force.

In order to solve the above-mentioned technical problems, the present invention provides a test system for measuring the coupling efficiency of the laser acting on the target, including a compound pendulum device for placing the target, a movable scale device for detecting the maximum swing angle of the compound pendulum, a detection light source, an oscilloscope, Trigger photoelectric sensor, action laser, action laser energy adjustment unit composed of half-wave plate and polarizer, energy meter and beam expander focusing lens group; compound pendulum device includes compound pendulum and compound pendulum bracket; compound pendulum consists of two compound pendulum rods frame, a support rod frame, a reflector mounted on the support rod frame, and a target fixing bracket; two complex swing rod frames, a support rod frame, and a target fixing bracket form a rectangular frame; the support rod frame is a metal sheet, and its lower edge is Sharp edges, the metal sheet is installed vertically on the upper ends of the two compound swing rod frames, and the target fixing bracket is installed on the lower ends of the two compound swing rod frames; The swing direction of the compound pendulum is vertical; the compound pendulum bracket is two metal sheets with sharp edges, the compound pendulum is placed on the compound pendulum support through the support rod frame, and the sharp edge of the support rod frame is in contact with the sharp edge of the compound pendulum bracket; it can be moved The scale device consists of a gigahertz photoelectric sensor, a one-dimensional translation stage, a horizontal slide rail and a scale that can slide along the horizontal slide rail; the gigahertz photoelectric sensor is fixed on the one-dimensional translation stage, and the one-dimensional translation stage is installed on the scale. And it can slide vertically along the ruler; the gigahertz photoelectric sensor and the one-dimensional translation stage are connected to the oscilloscope on the slide rail, and the oscilloscope is connected to the trigger photoelectric sensor.

Further, the detection light emitted by the detection light source is reflected by the reflector on the compound pendulum device, and is vertically incident on the photosensitive surface of the gigahertz photoelectric sensor in the movable scale device; the half-wave plate, polarizer and beam expander focusing lens group The optical axis coincides with each other, and the spot center of the active laser on the target coincides with the center of the target.

Further, when detecting a small deflection angle of the compound pendulum, adjust the position of the one-dimensional translation stage on the horizontal slide rail to keep the gigahertz photoelectric sensor away from the compound pendulum; The position on the slide rail makes the gigahertz photoelectric sensor close to the compound pendulum, and the displacement difference between the starting position and the ending position of the photoelectric sensor corresponding to the maximum swing angle of the compound pendulum is reduced to within the moving range of the one-dimensional translation platform.

Further, the calibration data set of the corresponding relationship between the swing angle of the complex pendulum and the displacement difference between the starting position and the end position of the gigahertz photoelectric sensor is determined through prior experiments, and the measurement of any maximum swing angle is realized by interpolating the corresponding relationship calibration data set .

Further, the method for obtaining the corresponding calibration data set is to align the center of the target on the target fixing bracket with a spiral micrometer, and make the irradiation center of the laser on the target coincide with the alignment position of the spiral micrometer, and The reading of the spiral micrometer at this time is used as the starting position of the target; the target is moved by a small displacement s through the spiral micrometer, and the end position of the gigahertz photoelectric sensor is recorded, so as to obtain the distance between the displacement s and the end position of the gigahertz photoelectric sensor The calibration data set of the corresponding relationship between them; then through the calibration data set of the corresponding relationship between the displacement s and the termination position of the gigahertz photoelectric sensor and the formula s=l sin(θ) to obtain the calibration data set of the corresponding relationship between the swing angle θ of the complex pendulum and the termination position of the photoelectric sensor .

Further, according to the following formula, when the energy of the i-th laser single pulse is E _i , the maximum impulse coupling coefficient C _i /C ₁ relative to the energy of the first laser single pulse is E ₁ ,

$\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}\sqrt{\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}}$

Among them, θ ₁ is the maximum swing angle of the complex pendulum when the laser single pulse energy is E ₁ , θ _i is the maximum swing angle of the complex pendulum when the laser single pulse energy is E _i , and C ₁ is the single laser pulse energy of one laser pulse is E ₁ The impulse coupling coefficient when , C _i is the impulse coupling coefficient when the i laser single pulse energy is E _i .

Compared with the prior art, the present invention has significant advantages in that: (1) between the compound pendulum and the compound pendulum bracket, the state of almost zero frictional resistance can be achieved through the contact and support of the sharp metal edge, so as to more realistically simulate the target in the absence of Test the impulse coupling efficiency of the laser on the target in the frictional suspension state; (2) realize the gigahertz high dynamic response range through the gigahertz photoelectric sensor; (3) increase and decrease the distance between the photoelectric sensor and the compound pendulum device (4) Measure the corresponding relationship between the swing angle of the compound pendulum and the displacement difference between the starting position and the ending position of the photoelectric sensor to calibrate the data set, so that the data set can be calibrated through the corresponding relationship Interpolation realizes the precise measurement of any maximum pendulum angle; (5) Eliminates the error that may be introduced due to the difficulty in determining the mass distribution of the complex pendulum through the non-dimensionalized impulse coupling efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the test system for the coupling efficiency of the impulse of the laser on the space debris of the present invention.

Fig. 2 is a schematic diagram of the compound pendulum device in the present invention.

Fig. 3 is a schematic diagram of the movable scale device in the present invention.

Fig. 4 is a schematic diagram when the compound pendulum device reaches the swing angle θ.

Fig. 5 is a calibration data set of the corresponding relationship between the displacement s of the center of the target on the compound pendulum along the positive direction of the x-axis and the termination position of the photoelectric sensor when the probe light can be incident on the center of the photosensitive surface of the photoelectric sensor.

Fig. 6 is a schematic diagram of the relationship between the impulse coupling efficiency and the energy density of the applied laser.

detailed description

It is easy to understand that, according to the technical solution of the present invention, without changing the essence of the present invention, those skilled in the art can imagine various implementations of the laser-to-target impulse coupling efficiency test system of the present invention. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the entirety of the present invention or as a limitation or limitation on the technical solution of the present invention.

Referring to accompanying drawing 1, the test system of the coupling efficiency of the laser on the target action impulse of the present invention is mainly composed of a compound pendulum device A for placing the target, a movable scale device B for detecting the maximum swing angle of the compound pendulum, a detection light source 17, Oscilloscope 10, trigger photoelectric sensor 11, action laser 12, action laser energy adjustment unit composed of half-wave plate 13 and polarizer 14, energy meter 15 and beam expander focusing lens group 16.

The compound pendulum device A includes a compound pendulum and a compound pendulum bracket 4 . The compound pendulum is made up of two complex pendulum rod frames 1, a support rod frame 5, a reflector 2 installed on the support rod frame 5, and a target fixing bracket 3. Two complex swing rod frames 1, support rod frames 5, and target fixing brackets 3 form a rectangular frame; the support rod frame 5 is a metal sheet, and its lower edge is a sharp edge, and the metal sheet is vertically installed on the upper ends of the two compound swing rod frames 1 , the target fixing bracket 3 is installed on the lower ends of the two compound swing rod frames 1; the two compound swing rod frames 1 are in the shape of a high-rigidity elongated sheet whose thickness direction is perpendicular to the swing direction of the compound swing rod. The compound pendulum bracket 4 is two sheets of metal with sharp edges. The compound pendulum is placed on the compound pendulum support 4 through the support bar frame 5 , and the sharp edge of the support bar frame 5 contacts with the sharp edge of the compound pendulum support 4 .

The movable scale device B is composed of a gigahertz photoelectric sensor 6 , a one-dimensional translation stage 7 , a horizontal slide rail 8 and a scale 9 that can slide along the horizontal slide rail 8 . The gigahertz photoelectric sensor 6 is connected to an oscilloscope 10 , and the oscilloscope 10 is connected to a trigger photoelectric sensor 11 . The gigahertz photoelectric sensor 6 is fixed on the one-dimensional translation platform 7, and the one-dimensional translation platform 7 is installed on the scale 9 by fastening screws, and can slide vertically along the scale 9. By adjusting the fastening screw that the one-dimensional translation platform 7 is connected with the scale 9, the one-dimensional translation platform 7 can slide on the scale 9, and the sliding direction of the gigahertz photoelectric sensor 6 and the one-dimensional translation platform 7 on the slide rail 8 is consistent with the photoelectric The photosensitive surface of the sensor is parallel to the normal direction.

In this embodiment, the detection light source 17 is a semiconductor continuous laser with a power of 75mw, whose output power changes less than 2% after 10 hours of continuous operation, and a wavelength of 660nm. When using this system, the detection light emitted by the detection light source 17 is reflected by the reflector 2 on the compound pendulum device A, and then vertically incident on the gigahertz photoelectric sensor 6 in the movable scale device B. The maximum single pulse energy of the action laser emitted by the action laser 12 is 440mJ, the pulse width is 7ns, and the wavelength is 1064nm. The optical axes of the half-wave plate 13, the polarizer 14, and the beam expander focusing lens group 16 are coincident, and the center of the spot of the applied laser light on the target coincides with the center of the target. When the acting laser is incident on the surface of the target, the impulse is transmitted to the target; then the compound pendulum used to fix the target will swing, and the maximum swing angle of the compound pendulum can be detected through the movable scale device B, so as to obtain the impulse coupling of the acting laser to the target efficiency.

(1) The present invention realizes a state of nearly no frictional resistance through contact and support of sharp metal edges.

In conjunction with Fig. 1, the compound pendulum device in the present invention utilizes a metal sheet 5 with a sharp edge and two highly rigid strip-shaped sheets fixed at both ends of the metal sheet 5 to form a compound swing rod frame 1, and the two highly rigid strip-shaped sheets The thickness direction is perpendicular to the swing direction of the compound pendulum, so as to minimize the deformation of the compound pendulum bar frame 1 in the direction of the force when it is subjected to the laser action to generate recoil pressure. The surface of the metal sheet 5 is attached to the reflector 2, so that the detection light is reflected to the photoelectric sensor during the swinging process of the compound pendulum. A target fixing bracket 3 is fixed between the other ends of the two high-rigidity elongated thin pieces of the complex pendulum frame 1 for placing targets.

The compound pendulum bracket 4 is composed of two pairs of obtuse-angled metal sheets with sharp edges, and the metal sheet 5 in the compound swing rod frame 1 is vertically placed on the compound pendulum support 4, so that the sharp edges of the compound pendulum bracket 4 and the metal sheet 5 contact with sharp edges. In this case, the contact point between the two is a nearly ideal geometric point, and the friction force tends to zero.

(2) The present invention realizes high dynamic response range, high sensitivity and large range through the combination of a gigahertz photoelectric sensor and a movable scale.

Referring to FIG. 2 , the photoelectric sensor 6 whose photoelectric response time rising edge is only 2ns is fixed on the one-dimensional translation stage 7 so that the spatial position of the photoelectric sensor 6 in the vertical direction can be read by the scale 9 . The one-dimensional translation stage 7 and the photoelectric sensor 6 are vertically fixed on the horizontal slide rail 8, and the sliding direction of the photoelectric sensor 6 and the one-dimensional translation stage 7 on the slide rail 8 is parallel to the normal direction of the photosensitive surface of the photoelectric sensor.

Referring to FIG. 1 , the detection light is reflected by the mirror 2 , and then incident on the center of the photosensitive surface of the photoelectric sensor 6 along the sliding direction of the slide rail 8 . The photoelectric sensor 6 is connected with an oscilloscope 10 for reading the detection light signal. First record the height of the photoelectric sensor 6 fixed on the one-dimensional translation platform 7 when the compound pendulum device is stationary is the vertical position of the compound pendulum, and as the starting position of the photoelectric sensor 6, it is the corresponding compound pendulum at 0 degree pendulum equivalent position at the corner. When the laser acts on the target, it will generate an impulse transfer to the compound pendulum to make the compound pendulum swing. At this time, by moving the one-dimensional translation platform 7 in the vertical direction, the photoelectric sensor 6 moves to the edge position that the vertical swing of the detection light can reach. At this time Record the height of the one-dimensional translation platform in the vertical direction as the end position of the photoelectric sensor 6, which is the equivalent position of the corresponding maximum swing angle of the compound pendulum. Owing to being connected with the oscilloscope 10, the oscilloscope 10 can just display a detection light signal as a sign that the photoelectric sensor reaches the termination position.

For the detection of the small deflection angle of the compound pendulum, by adjusting the position of the one-dimensional translation platform 7 on the horizontal slide rail 8, the photoelectric sensor 6 is kept away from the compound pendulum, thereby amplifying the initial position of the photoelectric sensor 6 corresponding to the maximum swing angle of the same compound pendulum. The displacement difference d and d between the end positions are read by the scale 9, which improves the measurement sensitivity of the test system for the tiny impulse transmission of the laser to the target. For the detection of the larger deflection angle of the compound pendulum, by adjusting the position of the one-dimensional translation platform 7 on the horizontal slide rail 8, the photoelectric sensor is brought close to the compound pendulum, thereby reducing the distance between the initial position of the photoelectric sensor 6 corresponding to the maximum swing angle of the same compound pendulum. The displacement difference d between the end positions is within the moving range of the one-dimensional translation stage, which improves the measurement range of the test system for the impulse transmission of the laser to the target.

(3) The present invention measures the complex pendulum swing angle θ and the displacement difference d corresponding relationship between the photoelectric sensor 6 starting position and the end position through prior experiments to calibrate the data set, thereby realizing any maximum swing angle by interpolating the corresponding relationship calibration data set precise measurement.

As shown in FIG. 2 , align the spiral micrometer 5 with the center of the target located on the target fixing bracket 3 , and the reading of the spiral micrometer at this time is used as the starting position of the target. And in the experimental test, the irradiation center of the laser on the target coincides with the alignment position of the spiral micrometer 5 . The target is moved by a small displacement s through the screw micrometer 5, and the end position of the photoelectric sensor 6 is recorded, so as to obtain a calibration data set of the corresponding relationship between the displacement s and the end position of the photoelectric sensor 6 . l is the distance between the suspension fulcrum of the compound pendulum and the center of the target, and θ is the swing angle of the compound pendulum. At this time, s=l·sin(θ) can be obtained. Then, the calibration data set of the corresponding relationship between the displacement s and the photoelectric sensor 6 termination position and the formula s=l sin(θ) can be obtained to obtain the calibration data set of the corresponding relationship between the swing angle θ of the complex pendulum and the photoelectric sensor 6 termination position, and then through the experimentally recorded The interpolation of the calibration data set of the correspondence relationship at the termination position of the photoelectric sensor 6 can obtain any reading of the complex pendulum swing angle θ.

(4) The present invention eliminates the error that may be introduced due to the difficulty in determining the mass distribution of the complex pendulum by dimensionless impulse coupling efficiency.

According to the following equations (1) and (2), the initial momentum p _i of the equivalent mass m of the compound pendulum device under the action of the energy E _i of the i-time laser single pulse when the equivalent pendulum length is L, the initial momentum p _i As shown in formula (3). h _i shown in formula (2) is the center of mass elevation distance of the compound pendulum device under the action of laser single pulse energy E _i . Since the present invention is concerned with finding the laser parameters that make the momentum coupling coefficient C _i maximize under the action of the i-th laser single pulse energy E _i of the compound pendulum device shown in formula (4), then the formula (5) can be used The dimensionless method is used to obtain the maximum impulse coupling coefficient C _i /C ₁ when the laser single pulse energy is E _i , compared to the first laser single pulse energy E ₁ .

$\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; mgh</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

h _i ＝L(1-cosθ _i )(2)

${\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; g</span>}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; g</span>}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

$\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; g</span>}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; /</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; g</span>}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}\sqrt{\frac{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; cos\&theta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Among them, θ ₁ is the maximum swing angle of the complex pendulum and the target when the laser single pulse energy is E ₁ , θ _i is the maximum swing angle of the complex pendulum and the target when the laser single pulse energy is E _i , C ₁ is 1 laser single pulse The impulse coupling coefficient when the energy is E ₁ , C _i is the impulse coupling coefficient when the i laser single pulse energy is E _i .

In this embodiment, the detection light source 17 is a semiconductor continuous laser with a power of 75mw, whose output power changes less than 2% after 10 hours of continuous operation, and a wavelength of 660nm. The detection light emitted by the detection light source 17 is reflected by the reflector 2 on the compound pendulum device A, and is vertically incident on the gigahertz photoelectric sensor 6 in the movable scale device B. The maximum single pulse energy of the action laser emitted by the action laser 12 is 440mJ, the pulse width is 7ns, and the wavelength is 1064nm. The optical axes of the half-wave plate 13, the polarizer 14, and the beam expander focusing lens group 16 are coincident, and the center of the spot of the applied laser light on the target coincides with the center of the target. The impact of the laser light on the surface of the target generates impulse transmission to the target; then the compound pendulum used to fix the target will swing, and the gigahertz photoelectric sensor 6 in the movable scale device B can detect the maximum swing angle of the compound pendulum, thereby Obtain the impulse coupling efficiency of the acting laser to the target.

When the target is in a static state, adjust the position of the detection light and the gigahertz photoelectric sensor 6 so that the detection light can be incident on the gigahertz photoelectric sensor 6 along the sliding direction of the horizontal slide rail 8 (i.e. the normal direction of the gigahertz photoelectric sensor 6). At the center of the photosensitive surface of the sensor 6, the oscilloscope 10 reads that the photoelectric signal measured by the gigahertz photoelectric sensor 6 reaches the maximum value, and records the height of the vertical direction of the gigahertz photoelectric sensor 6 as the starting point of the gigahertz photoelectric sensor 6 Location. Before the measurement starts, calibrate the data set of the corresponding relationship between the displacement s of the center of the target on the compound pendulum along the positive direction of the x-axis and the termination position of the gigahertz photoelectric sensor 6 when the probe light can be incident on the center of the photosensitive surface of the gigahertz photoelectric sensor 6, such as Figure 3 shows. When the active laser 12 emits light in a single pulse, the trigger photoelectric sensor 11 triggers the oscilloscope 10 to start recording the detection light signal obtained by the gigahertz photoelectric sensor 6, so as to obtain the corresponding maximum displacement of the gigahertz photoelectric sensor 6 when the compound pendulum reaches the maximum swing angle d, so that the maximum displacement s of the target center can be obtained through the interpolation of the corresponding calibration data set, and then the maximum swing angle θ of the compound pendulum can be calculated; at the same time, the single pulse energy of the laser 12 is monitored by the energy meter 15, so as to calculate the energy coupling efficiency. The active laser energy adjustment unit composed of half-wave plate 13 and polarizer 14 changes the laser energy acting on the target from small to large, and records the maximum swing angle of the compound pendulum corresponding to each laser energy, and conducts 5 tests to get the average value. After completing a set of experiments, the change curve of the impulse coupling coefficient to the target is obtained by calculating the energy of the laser single pulse through formula (5), and then the laser energy density at which the impulse coupling efficiency is maximized is obtained, as shown in Figure 4.

In the present invention, the contact edge between the compound pendulum and the compound pendulum bracket is sharp to reduce friction as much as possible, and the detection light is reflected to the photoelectric sensor through the reflector fixed on the compound pendulum rod frame to detect the maximum swing angle of the compound pendulum; the movable scale device It can easily capture the impulse transfer effect generated by the high-speed transient source on the target, and adapt to the test range of different compound pendulum swing angles; calibrate the data set by measuring the corresponding relationship between the compound pendulum swing angle and the displacement difference between the starting position and the ending position of the photoelectric sensor, Therefore, the precise measurement of any maximum pendulum angle can be realized by interpolating the corresponding calibration data set; the error that may be introduced by the measurement of the mass distribution of the complex pendulum can be eliminated by the non-dimensionalized impulse coupling efficiency. The measured impulse coupling efficiency applicable to the present invention can be the impulse coupling efficiency of targets of various materials under laser irradiation, or the impulse of the target under the action of instantaneous pulse force such as magnetic force pulse, liquid or gas jet impact, bullet impact, etc. coupling efficiency.

Claims (6)

1. a laser is to target effect Impulse coupling efficiency test system, it is characterized in that, comprise the pendulum device (A) for placing target, for detecting the removable scale device (B) of physical pendulum maximum pendulum angle, probe source (17), oscillograph (10), trigger photoelectric sensor (11), effect laser instrument (12), the effect laser energy regulon be made up of half-wave plate (13) and polaroid (14), energy meter (15) and expand focus lens group (16);

Pendulum device (A) comprises physical pendulum and physical pendulum support (4); Physical pendulum is made up of two physical pendulum bridges (1), bracing member (5), the catoptron (2) be arranged on bracing member (5), target fixed support (3); Two physical pendulum bridges (1), bracing member (5), target fixed supports (3) form rectangular frame; Bracing member (5) is sheet metal, and its lower limb is sharp edges, and sheet metal is vertically mounted on the upper end of two physical pendulum bridges (1), and target fixed support (3) is arranged on the lower end of two physical pendulum bridges (1); Two physical pendulum bridges (1) are high rigidity strip flake, and its thickness direction is vertical with physical pendulum swaying direction; Physical pendulum support (4) has the sheet metal of sharp edges for two panels, physical pendulum is placed on physical pendulum support (4) by bracing member (5), and the sharp edges of bracing member (5) contacts with the sharp edges of physical pendulum support (4);

Removable scale device (B) is made up of Gigahertz photoelectric sensor (6), one dimension translation stage (7), horizontal slide rail (8) and the scale (9) that can slide along horizontal slide rail (8); Gigahertz photoelectric sensor (6) is fixed on one dimension translation stage (7), and one dimension translation stage (7) is arranged on scale (9), and can slide in the vertical direction along scale (9); (glide direction on 8 is parallel with photoelectric sensor light-sensitive surface normal direction at slide rail for Gigahertz photoelectric sensor (6) and one dimension translation stage (7); Gigahertz photoelectric sensor (6) is connected with oscillograph (10), and oscillograph (10) is connected with triggering photoelectric sensor (11).

2. as claimed in claim 1 laser to target effect Impulse coupling efficiency test system, it is characterized in that, the detection light that probe source (17) sends, via after catoptron (2) reflection in pendulum device (A), impinges perpendicularly on the light-sensitive surface of the Gigahertz photoelectric sensor (6) in removable scale device (B); Half-wave plate (13), polaroid (14) and expand the optical axis coincidence of focus lens group (16), and make the spot center of effect laser on target and target center superposition.

3. as claimed in claim 1 laser to target effect Impulse coupling efficiency test system, it is characterized in that, when detecting the small deflection angle of physical pendulum, regulate one dimension translation stage (7) position on horizontal slide rail (8), make Gigahertz photoelectric sensor (6) away from physical pendulum; Detection physical pendulum comparatively large deflection angle time, regulate one dimension translation stage (7) position on horizontal slide rail (8), make Gigahertz photoelectric sensor (6) near physical pendulum, within photoelectric sensor (6) displacement difference between reference position and final position corresponding for physical pendulum maximum pendulum angle is narrowed down to one dimension translation stage moving range.

4. as claimed in claim 1 laser to target effect Impulse coupling efficiency test system, it is characterized in that, the corresponding relation nominal data collection of displacement difference between reference position and final position by priori measuring physical pendulum pivot angle and Gigahertz photoelectric sensor (6), by realizing the measurement of any maximum pendulum angle to this corresponding relation nominal data collection interpolation.

5. as claimed in claim 1 laser to target effect Impulse coupling efficiency test system, it is characterized in that, the method obtaining corresponding relation nominal data collection is, screw-thread micrometer (5) is used to aim at the target center being positioned at (3) on target fixed support, and the Radiation Center of laser on target is overlapped, using screw-thread micrometer reading now as target reference position with the aligned position of screw-thread micrometer (5); Target is made to move micro-displacement s by screw-thread micrometer (5), and record the final position of Gigahertz photoelectric sensor (6), thus obtain corresponding relation nominal data collection between displacement s and Gigahertz photoelectric sensor (6) final position; Then pass through displacement s and Gigahertz photoelectric sensor (6) final position corresponding relation nominal data collection and formula s=lsin (θ) and obtain physical pendulum pivot angle θ and photoelectric sensor (6) final position corresponding relation nominal data collection.

6. laser, to target effect Impulse coupling efficiency test system, is characterized in that as claimed in claim 1, obtains when i-th laser single-pulse energy is E according to following formula _itime, relative 1st laser single-pulse energy is E ₁time maximum thrust coupling coefficient C _i/ C ₁,

$\frac{C_i}{C_1}=\frac{E_1}{E_i}\sqrt{\frac{(1-{\mathrm{cos\&theta;}}_i)}{(1-{\mathrm{cos\&theta;}}_1)}}$

Wherein, θ ₁be laser single-pulse energy be E ₁time physical pendulum maximum pendulum angle, θ _ibe laser single-pulse energy be E _itime physical pendulum maximum pendulum angle, C ₁be 1 laser single-pulse energy be E ₁time impulse coupling coefficient, C _ibe i laser single-pulse energy be E _itime impulse coupling coefficient.