CN103594913B - The magnetic confinement device of HeNe laser pack and method - Google Patents

Abstract

The invention relates to a magnetic confinement device and method for HeNe laser beam focusing, and relates to the technical field of laser measurement. The device includes in turn: a four-dimensional motion platform (101) for placing the HeNe laser (102), a magnetic confinement device for converging the laser beam, and a spot size sensor (109) for detecting the laser converging performance; the above-mentioned magnetic confinement The device mainly includes a mutually repulsive magnetic confinement body (108) that can rotate at high speed. The mutually repulsive magnetic confinement body (108) is composed of multiple pairs of magnets with opposite polarities, forming a magnetic cavity (107) in the middle, and the HeNe laser (102) emits A laser beam can pass through the magnetic cavity (107). When the laser passes through the magnetic cavity, because the laser light is deflected in the mutually repulsive magnetic field, the peripheral light of the laser beam is shifted to the center, so as to achieve the purpose of improving the laser focusing performance.

Description

Magnetic confinement device and method for HeNe laser beam focusing

technical field

The invention relates to the technical field of laser detection, more specifically, it is a magnetic confinement of a HeNe laser beam focusing that uses a mutually exclusive magnetic confinement body to improve the performance of HeNe laser beam focusing, thereby improving laser alignment, testing accuracy and range. Devices and methods.

Background technique

Under the action of a magnetic field, the optical properties of light will change. Previous studies include Zeeman effect, Faraday magneto-optic effect, Cotton-Mouton effect and Kerr magneto-optic effect. These effects all originate from the magnetization of matter, reflecting the connection between light and the magnetism of matter.

Michael Faraday found that when linearly polarized light propagates in a medium, if a strong magnetic field is applied parallel to the propagation direction of the light, the light vibration direction will be deflected, and the deflection angle ψ is proportional to the product of the magnetic induction intensity B and the length L of light passing through the medium Proportional, that is, ψ=VBL. The deflection direction depends on the properties of the medium and the direction of the magnetic field. This phenomenon is called the magneto-optical rotation effect. This effect can be used to analyze hydrocarbons, because each hydrocarbon has its own magneto-optical rotation characteristics; it can be used to isolate reflected light in laser technology, and can also be used as a means of modulating light waves.

Aimé Cotton and Henri Mouton found that when light propagates in a transparent liquid medium, if an external magnetic field is applied perpendicular to the direction of light propagation, the medium exhibits the properties of a uniaxial crystal, the optical axis is along the direction of the magnetic field, and the difference between the principal refractive indices is proportional to The square of the magnetic induction, this effect is called magnetically induced birefringence.

KerrJohn discovered that when the incident linearly polarized light is reflected on the surface of a magnetized material, the vibration plane rotates, which is called Magneto-Optic KerrEffect (MOKE). MOKE is divided into three types: polar direction, longitudinal direction and transverse direction, respectively corresponding to the three situations in which the magnetization of the material is perpendicular to the reflecting surface, parallel to the surface and incident surface, and parallel to the surface and perpendicular to the incident surface. The magneto-optical rotation of the poloidal and longitudinal Kerr magneto-optical effects is proportional to the magnetization intensity. Generally, the effect of the poloidal direction is the strongest, followed by the longitudinal direction, and there is no obvious magneto-optic rotation in the transverse direction. Different magnetic domains have different spontaneous magnetization directions, which cause different rotations of the vibration plane of the reflected light. When the reflected light is observed through a polarizer, different light and dark areas corresponding to each magnetic domain will be observed.

The above studies have all explained the phenomenon of laser deflection in a magnetic field. However, there is no relevant research and report on the method and device for laser beam deflection and bunching under the action of a mutually repulsive magnetic field.

The low-power HeNe infrared lasers used in the laser measurement process include laser interferometers, laser trackers, theodolites, etc. The advantages of such instruments lie in large-scale measurement, especially in large-scale aircraft assembly, shipbuilding and other fields. So far, lasers have been widely used in these fields, but it is very difficult to achieve a high precision for ultra-large-scale laser alignment and measurement. This is because the laser beam has a divergence angle. After a large distance travel, the laser divergence is very serious, and high-precision detection cannot be achieved. At present, the most precise laser divergence angle at home and abroad reaches 0.1mrad, that is, the length of 80 meters is collimated, and the diameter of the spot is about 8mm. The accuracy cannot meet the demand, and the energy density cannot meet the requirements for use.

Therefore, the present invention proposes a laser beam focusing method and device of mutual repulsion magnetic confinement. By changing the divergence angle of the emitted laser light, the laser beam is promoted to realize ultra-long-distance laser transmission and precise detection. It brings huge economic benefits and technical support to the technical fields related to laser alignment and measurement in my country, including shipbuilding and aerospace assembly.

Contents of the invention

The object of the present invention is to provide a magnetic confinement method and device for HeNe laser beam focusing to achieve the purpose of improving the laser beam focusing performance.

A magnetic confinement device for HeNe laser beam focusing, which is characterized in that: sequentially comprising: a four-dimensional motion platform for arranging HeNe lasers, a magnetic confinement device for laser beam focusing, and a spot size sensor for detecting laser beam focusing performance The above-mentioned magnetic restraint device includes a precision guide rail, a bearing bracket installed on the precision guide rail, and a horizontal bearing installed in the bearing bracket; it also includes a constraining body rotating bracket installed in the horizontal bearing, and the constraining body rotating bracket is a hollow shaft structure. The hollow shaft structure is also embedded with a mutually exclusive magnetic confinement body, which is composed of multiple pairs of magnets with opposite polarities, forming a magnetic cavity in the middle, and the laser beam emitted by the HeNe laser can pass through the magnetic cavity; A rotation drive mechanism connected to one end of the rotation bracket of the constraining body.

The method for the magnetic confinement device of the HeNe laser beam focusing is characterized in that it includes the following process: when the laser light emitted by the HeNe laser passes through the magnetic cavity formed by the mutually repulsive magnetic confinement body, because the laser light generates light in the mutually repulsive magnetic field The deflection makes the peripheral light of the laser beam shift towards the center, so as to achieve the purpose of improving the laser beam focusing performance; and the improvement of the laser beam focusing performance can be judged by the spot diameter, and the size of the spot diameter can be detected by the spot scale sensor; The change of the bunching performance is changed by adjusting the magnetic field strength in the magnetic cavity, and the magnetic field strength of the magnetic cavity is related to the diameter and length of the magnetic cavity. As the magnetic field strength increases, the diameter of the magnetic cavity becomes smaller, and the beamforming performance improves. On the contrary, the magnetic field strength decreases, the diameter of the magnetic cavity becomes larger, and the bunching performance decreases.

Because the laser beam has a divergence angle, after a large distance travel, the laser divergence is very serious, and high-precision detection cannot be achieved. Aiming at this problem, the present invention proposes a magnetic confinement method and device for HeNe laser beam focusing, using N-N/S-S strong mutually repulsive magnetic fields to act on the laser beam to perform beam focusing and compression on the laser beam to realize the divergence of the epitaxial laser beam angle deflection. Using the strong permanent magnetic mutual repulsion field and the adjustable intensity electromagnetic mutual repulsion field, changing the magnetic field characteristic parameters such as the inner diameter of the magnetic cavity, the number of magnetic pole pairs, and the length of the magnetic cavity, and using the laser spot diameter as the index parameter, the detection of the change of the laser beam spotting characteristics is realized. An isotropic rotating mutually repulsive magnetic field is proposed to avoid the influence of anisotropic magnetic field on the laser focusing performance, and a set of methods and system devices for magnetically confining laser with high focusing characteristics are established. The invention will provide key theories and supporting technologies for research and development in the fields of laser measurement, aerospace, shipbuilding and the like in my country. In the present invention, in order to ensure that the magnetic confinement body can pass through the laser, the rotating bracket of the magnetic confinement body is designed as a hollow shaft through which the laser light can pass. When the laser beam passes through the magnetic cavity, it should be ensured that the laser beam can pass through the center of the head and tail holes of the magnetic cavity. Therefore, the laser beam can pass through the center of the magnetic cavity by adjusting the pose of the laser beam through the four-dimensional motion platform. Adjust the position between the mutually exclusive magnetic confinement body and the HeNe laser to find the most suitable distance for focusing the laser beam. The bearing bracket is on the precision guide rail, and the straightness of the guide rail is very high, so as to ensure that the laser focusing performance will not be affected when the mutually repulsive magnetic confinement body moves axially on the guide rail. The improvement of laser beam focusing performance is detected by the spot size sensor, which is also installed on the central axis of the precision guide rail to ensure that the laser basically hits the center of the sensor.

The mutually repelling magnetic constraints are in the form of permanent magnets or electromagnets. When the mutually exclusive magnetic confinement body is in the form of a permanent magnet, the change of the length of the magnetic cavity is realized by adjusting the axial length of the permanent magnet; the change of the diameter of the magnetic cavity is realized by adjusting the distance between the pairs of magnetic poles in the mutually exclusive magnetic confinement Realize that the distance between the magnetic pole pairs decreases, the magnetic cavity decreases, and the magnetic field intensity increases; on the contrary, the distance between the magnetic pole pairs increases, the magnetic cavity increases, and the magnetic field intensity decreases. When the mutually exclusive magnetic confinement body is formed by an electromagnet, the change of the length of the magnetic cavity is realized by connecting a plurality of electromagnets in series in the axial direction. When the number of electromagnets connected in series increases, the length of the magnetic cavity increases; the diameter of the magnetic cavity The change is realized by adjusting the current of the electromagnet coil, the current increases, the diameter of the magnetic cavity decreases, and the current decreases, the diameter of the magnetic cavity increases.

Description of drawings

Fig. 1 is a structural diagram of a magnetic confinement body focusing device of the present invention;

Label names in Figure 1: 101—four-dimensional motion platform; 102—HeNe laser; 103—precision guide rail; 104—bearing bracket; 105—horizontal bearing; 106—constraining body rotating bracket; 107—magnetic cavity; ; 109—spot size sensor; 110—driven pulley; 111—drive belt; 112—motor; 113—driving pulley.

detailed description

A magnetic confinement method and device for HeNe laser beam focusing of the present invention will be described below with reference to the accompanying drawings.

As shown in Figure 1, the magnetic confinement method and device of the HeNe laser beam focusing of the present invention include:

The four-dimensional motion platform 101, on which the laser is installed, realizes the control and adjustment of the position and posture of the laser, and ensures that the laser beam passes through the center of the magnetic cavity;

HeNe laser 102, a device for emitting HeNe low-power laser;

The precision guide rail 103 adjusts the position between the mutually exclusive magnetic confinement body and the HeNe laser, and finds the most suitable distance for focusing the laser beam;

Bearing bracket 104 supports the bearing and is connected to the precision guide rail at the same time to ensure that the bearing can rotate at high speed;

Horizontal bearing 105, the magnetic constraint body clamped by the hollow shaft is installed on the bearing to ensure the high-speed rotation of the magnetic constraint body and provide an isotropic magnetic field;

Constraining body rotating bracket (hollow shaft) 106 clamps the magnetic constraining body formed by the permanent magnet and the electromagnet, and can realize the adjustment of the distance between the magnetic poles for the electromagnet, and can be assembled on the bearing for rotation; the hollow shaft center hole and the magnet The center hole of the cavity should be as coaxial as possible;

The magnetic cavity 107 is a cylindrical magnetic field area formed by a permanent magnet or an electromagnet, and the variable parameters include two parameters: the diameter of the magnetic cavity and the length of the magnetic cavity;

The mutually exclusive magnetic confinement body 108 is a mutually exclusive magnetic confinement body composed of N-N or S-S, which forms a deflection effect on the laser;

The spot size sensor 109 is installed on the precision guide rail, and is used to detect the diameter of the spot before and after the laser is focused, so as to reflect the change of the focusing performance of the spot by the magnetic confinement body;

The driven pulley 110 is in interference fit with the hollow shaft, and realizes the rotation of the magnetic restraint body together with the transmission belt, providing an isotropic magnetic cavity;

Drive belt 111: connect the pulley and the motor driving wheel to form a belt drive chain;

Motor 112: providing a power source for the rotation of the magnetically constrained body;

The driving pulley 113 is connected with the motor and the transmission belt, and transmits the rotational motion of the motor to the driven pulley to realize the rotation of the magnetic restraint body.

As shown in Figure 1, during the detection process, the magnetic confinement method and device for HeNe laser beamforming are implemented as follows:

Step 1: Adjust the distance of the magnetic confinement body for the electromagnet, adjust the coil current for the permanent magnet, and form a magnetic cavity with a certain diameter and length;

Step 2: Under the action of the four-dimensional motion platform, adjust the laser position and orientation, and with the assistance of the PSD sensor, use the computer control algorithm to realize that the laser passes through the center of the head and tail holes of the magnetic cavity at the same time;

Step 3: On the precision guide rail, adjust the position between the mutually exclusive magnetic confinement body and the HeNe laser to find the most suitable distance for focusing the laser beam;

Step 4: Use the spot size sensor to detect the spot diameter to reflect the laser beam focusing performance, measure the spot size before and after applying magnetic confinement, and compare the spot size before and after the laser beam focusing;

Step 5: Connect the driven pulley on the magnetic restraint body and the driving pulley of the motor through a transmission belt;

Step 6: Rotate the motor to generate an isotropic magnetic field, and observe the improvement in laser beamforming performance in the case of an isotropic magnetic field (motor rotating) and an anisotropic magnetic field (motor stopped).

Step 7: Use the device of the present invention to apply an isotropic magnetic confinement body to any measuring laser or collimated laser to improve the beam focusing performance of the laser and realize the ultra-long-distance precision laser testing function.

Claims (6)

1. a magnetic confinement device for HeNe laser pack, is characterized in that:

Comprise successively: for settling the four-dimensional movement platform (101) of HeNe laser (102), for making the magnetic confinement device of laser pack, the hot spot dimension transducer (109) for detection laser pack performance;

Above-mentioned magnetic confinement device comprises precise guide rail (103), the support of bearing (104) be installed in precise guide rail (103), the horizontal bearing (105) be installed in the support of bearing (104); Also comprise the obligatory point runing rest (106) be installed in horizontal bearing (105), obligatory point runing rest (106) is hollow shaft structure, setting-in mutual exclusion magnetic confinement body (108) is gone back in this hollow shaft structure, this mutual exclusion magnetic confinement body (108) is made up of N-N or S-S, middle formation magnetic cavity (107), the laser beam that HeNe laser (102) sends can pass this magnetic cavity (107); Also comprise the rotary drive mechanism be connected with obligatory point runing rest (106) one end.

2. the magnetic confinement device of HeNe laser pack according to claim 1, is characterized in that: described mutual exclusion magnetic confinement body (108) is permanent magnet form or electromagnet form.

3. the magnetic confinement device of HeNe laser pack according to claim 1, is characterized in that: above-mentioned rotary drive mechanism is made up of motor (112), the driving pulley (113) be connected with motor output shaft, the driven pulley (110) being installed on obligatory point runing rest (106) one end, the driving belt (111) that is connected driving pulley (113) and driven pulley (110).

4. the method for work of the magnetic confinement device of HeNe laser pack according to claim 1, is characterized in that comprising following process:

When the laser that HeNe laser (102) sends is through magnetic cavity (107) that formed by mutual exclusion magnetic confinement body (108), because there is light deflection in laser in mutual exclusion magnetic field, make the peripheral light of laser beam toward off-centring, thus realize the object of laser pack performance raising;

And the raising of laser pack performance can be judged by spot diameter, the size of spot diameter can be detected by hot spot dimension transducer (109);

The change of laser pack performance is changed by the size of magnetic field intensity in adjustment magnetic cavity (107), and the size of magnetic cavity (107) magnetic field intensity and magnetic cavity diameter, magnetic cavity length are relevant.

5. the method for the magnetic confinement device of HeNe laser pack according to claim 4, is characterized in that comprising following process:

When described mutual exclusion magnetic confinement body (108) is for permanent magnet form, the change of magnetic cavity length is realized by the adjustment of permanent magnet axial length; The change of magnetic cavity diameter is realized by the adjustment of pole pair spacing each in mutual exclusion magnetic confinement body (108).

6. the method for the magnetic confinement device of HeNe laser pack according to claim 4, is characterized in that comprising following process:

When described mutual exclusion magnetic confinement body (108) is formed for electromagnet, the change of magnetic cavity length is realized by the multiple electromagnet of axial series, and the electromagnet quantity of series connection increases, then magnetic cavity length increases; The change of magnetic cavity diameter is realized by the adjustment of electromagnet coils size of current, and electric current increases, and magnetic cavity diameter reduces, and electric current reduces, and magnetic cavity diameter increases.