CN212458661U - Light polarization state detection system - Google Patents

Abstract

The utility model belongs to the field of light measurement and discloses a light polarization state detection system, which comprises an optical system and a data acquisition system; the optical system comprises a laser generator, a first polaroid, a first 1/4 wave plate, a second 1/4 wave plate, a second polaroid and a light detector which are sequentially arranged along the same optical axis, wherein a 1/4 wave plate is arranged on a rotary mirror bracket which is arranged on an electric rotary table, and the electric rotary table is driven to rotate by a stepping motor; the data acquisition system comprises a main control chip, a motor driver and a direct current power supply, wherein the main control chip is connected with an upper computer, the motor driver and the main control chip are powered by the direct current power supply, the input end of the motor driver is connected with the output end of the main control chip, and the output end of the motor driver is connected with the stepping motor; the output end of a photoelectric sensor in the optical detector is connected with the input end of the main control chip. The utility model discloses utilize one set of optical equipment + one set of data acquisition device to realize the detection to the polarization state promptly.

Description

Light polarization state detection system

Technical Field

The utility model belongs to the light measurement field, concretely relates to light polarization state detecting system.

Background

For the research on the polarization state measurement technology, the prior art often uses a partial amplitude method and a modulation method to measure the packets vector. The method is characterized in that the polarization state of a light beam is measured by an amplitude splitting method, one incident light beam is split into four outgoing light beams by the amplitude splitting method, each split light beam carries different polarization modulation information, and the outgoing light beams are received by a detector with unified calibration. However, the method has complex structure, a large number of required detectors, difficult data acquisition and large equipment volume. In the conventional modulation method, a plurality of groups of data need to be collected and then calculated, so that real-time measurement cannot be realized, and the polarization state of light cannot be visually displayed. Meanwhile, errors caused by mechanical rotation exist, and the measurement precision is influenced.

Disclosure of Invention

The utility model aims at manufacturing a light polarization state measuring device, optical equipment, control motor drive, data acquisition and data display storage are as an organic whole, have solved current measuring instrument device complicacy, read the data difficulty, and the precision is low, the not directly perceived scheduling problem of experimental result.

The utility model adopts the following technical scheme:

a light polarization state detection system comprises an optical system and a data acquisition system; the optical system comprises a laser generator, a first polaroid, a first 1/4 wave plate, a second 1/4 wave plate, a second polaroid and a light detector which are sequentially arranged along the same optical axis, wherein a 1/4 wave plate is arranged on a rotary mirror bracket which is arranged on an electric rotary table, and the electric rotary table is driven to rotate by a stepping motor; the data acquisition system comprises a main control chip, a motor driver and a direct current power supply, wherein the main control chip is connected with an upper computer, the motor driver and the main control chip are powered by the direct current power supply, the input end of the motor driver is connected with the output end of the main control chip, and the output end of the motor driver is connected with the stepping motor; the output end of a photoelectric sensor in the optical detector is connected with the input end of the main control chip. The main control chip obtains the photoelectric sensor signal promptly, and the main control chip passes through motor drive ware and then controls step motor rotatory to the drive of electric turntable simultaneously.

An amplifying and filtering circuit is arranged between the input ends of the main control chip at the output end of the photoelectric sensor, and the amplifying and filtering circuit is powered by a direct current power supply through a power supply conversion module.

The stepping motor adopts a 2-phase stepping mode, and the rotation angle is 1.8 degrees.

The rotation angle of the 1/4 wave plate II is 0 degree, 30 degrees, 45 degrees and 60 degrees.

The main control chip is an Arduino single chip microcomputer.

The electric rotating platform is a PX-GD60 high-precision electric rotating platform.

And the upper computer connected with the main control chip is a LabVIEW virtual instrument.

The utility model discloses following beneficial effect has:

the device of the utility model is simple, and only one set of optical equipment and one set of data acquisition device are needed;

the utility model adopts the mechanical rotation and the photocell to acquire data in real time, and has simple and convenient operation and high measuring speed;

thirdly, the measurement precision is high, and a PX-GD60 high-precision electric rotating table is adopted;

and fourthly, the system is divided into a motor driving module, a photoelectric conversion module, a conditioning signal module, an AD conversion module and a serial port communication module. The accuracy, stability and high efficiency of system measurement are ensured by a modular design idea, a simple hardware circuit design and a parallel data processing flow, and the cost performance of the detection system is greatly improved; compared with the existing instrument, the multifunctional instrument has the characteristics of small size and convenience in use, and is more convenient for teaching and scientific research.

Fifthly, the utility model discloses use LabVIEW's powerful to accomplish data from communication, analysis, processing, show the whole process of storage to reach the sexual valence relative altitude, fast, wide, the instrument interface friendly of scope, show effect such as the result is directly perceived abundantly, as shown in fig. three.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention;

FIG. 2 is a schematic diagram of an optical system;

FIG. 3 LabVIEW interface diagram;

FIG. 4 is a schematic diagram of a data acquisition system;

FIG. 5 is a block diagram of the system of the present invention;

FIG. 6 is a schematic view of a motorized turntable;

FIG. 7 is a wiring diagram of a motor drive;

FIG. 8 is an enlarged filter circuit diagram of the photosensor;

FIG. 9 is a LabVIEW flow diagram;

FIG. 10 is a graph of LabVIEW formula node calculation parameters;

FIG. 11 is a graph of the measurement results x-y, a three-dimensional graph showing;

in the figure: the device comprises a 1-laser generator, a 2-polaroid I, a 3-1/4 wave plate I, a 4-1/4 wave plate II, a 5-polaroid II, a 6-photodetector (photoelectric sensor), a 7-main control chip, an 8-stepping motor and a 9-rotating mirror frame.

Detailed Description

Fig. 1 is a schematic diagram of the system of the present invention, which mainly includes three parts: optical system, data acquisition, virtual instrument.

A first part: an optical system as shown in fig. 2. The optical system is composed of a laser generator 1, a polaroid I2, a 1/4 wave plate I3, a 1/4 wave plate II 4, a polaroid II 5 and a light detector 6, and the combination of the polaroid I2 and the 1/4 wave plate I3 is used for manufacturing different types of polarized light: when only the polarizer I2 is placed, the polarizer is linearly polarized light; and when the optical axis included angle of the first polarizer 2 and the first 1/4 wave plate 3 is 45 degrees, the polarizer is circularly polarized light, and the other angles are elliptically polarized light. 1/4 wave plate two 4 and polarizer two 5 are analyzer. The rotary mirror bracket is controlled by the Arduino single chip microcomputer to enable the 1/4 wave plate II 4 to rotate to four special angles: and the light intensity is detected by a photoelectric sensor of the light detector 6 at 0 degrees, 30 degrees, 45 degrees and 60 degrees, and the data acquisition of the next stage is carried out. Wherein, electronic revolving stage is current market spare, its principle and basic mounting means the utility model discloses do not describe repeatedly.

A second part: and (6) data acquisition. The present embodiment provides a system integrating motor driving and data acquisition. As shown in fig. 4, a PX-GD60 high-precision electric rotary table in a motor driving circuit is connected to a TC8642 type two-phase hybrid stepping motor driver, the stepping motor adopts a 2-phase stepping mode, the rotation angle is 1.8 °, the used power voltage range is 24V ± 10%, a control interface is a DB9 male connector, and the stepping motor is connected to the driver through the interface. As shown in fig. 7, the + V, GND of the driver is connected with a power supply, + V is connected with a positive level of a direct-current power supply, the power supply voltage is direct current of 16-50V, the maximum current is 5A, and GND is connected with a negative level of the direct-current power supply; a + A-B + B-of the driver is connected with the two-phase hybrid stepping motor. The motorized rotary stage is controlled to rotate by Arduino to achieve mechanical rotational modulation of the optical part. The optical signal obtained by the optical part is converted into an electric signal through an S1133 Hamamatsu photosensitive photodiode silicon photocell to obtain an original electric signal; the electrical signal obtained from the photosensor may be weak or non-linear or contain a significant amount of noise that must be conditioned prior to analog-to-digital conversion. The signal conditioning is to improve the measurement precision by controlling signals, and the types of signal conditioning include amplification, linearization, attenuation, filtering, sensor excitation, isolation and the like. The signal conditioning of the system comprises two parts, namely, the output signal of the optical detector is subjected to pre-amplification, and an amplification filter circuit is shown in figure 8; secondly, the amplitude of the signal after pre-amplification is adjusted to a range suitable for analog-to-digital conversion in a program control mode. The original electrical signal is transmitted into Arduino for AD conversion after passing through the signal conditioning circuit, wherein the Arduino has 6 pins (A0-A5) which are specially used for AD conversion, and can convert the voltage signal into a value represented by 10 bits, the measuring range is 0-5V, the maximum value is 1023, and the minimum value is 0. Analog to digital conversion function by arduino: int analog read (agent 8_ t) (input port of analog signal in bracket), the return value of port is the digital value of analog signal conversion, the maximum value is 1023 to 5V, and the minimum value is 0 to 0V. After digital-to-analog conversion, the signal is transmitted to the host computer through Arduino, and then the next stage of data processing is carried out.

And a third part: a virtual instrument. The utility model discloses use LabVIEW virtual instrument platform to accomplish pc end software design part.

Parameters detectable with the system include: the electric rotating table respectively rotates to 0 degree, 30 degrees, 45 degrees and 60 degrees to measure the light intensity. The appropriate amount of stokes, the type of light polarization state, the Pongamer sphere, and the x-y image were obtained by LabVIEW calculation.

The specific detection process is as follows:

and in the detection process, the rotation of the wave plate is controlled by adopting a mechanical rotation method. The polaroid is fixed, the 1/4 wave plate II is placed on the rotating platform, the Arduino control stepping motor drives the rotating platform PC-GD60 to rotate, and then the optical axis of the 1/4 wave plate II rotates along with the rotation. Changing the direction of its optical axis to take several sets of special values, e.g.

The photosensitive photodiode silicon photocell of the hamamatsu is detected through the photoelectric sensor S1133, the signal conditioning circuit amplifies, filters and turns into voltage signal with the electric signal to measure with Arduino, transmit the measured light intensity data to the computer through the communication of Arduino serial port, according to the formula:

solving four Stokes parameters of measured light by using LabVIEW virtual instrument

The normalization processing is carried out on the numerical values to obtain the Stokes vector values of the light, and the polarization state of the light is judged and visually displayed.

The software part adopts a modular design, and the functions of each module are set as data communication, data processing, data display and data storage. And the data communication part is used for carrying out a control command through a LabVIEW serial interface, establishing communication with the Arduino, sending a control motor command to the Arduino and receiving data obtained by measurement of the Arduino. And the data processing part substitutes the received data into a Stokes vector calculation formula and calculates the related parameters by using a MathScript node of LabVIEW having a text programming language function. And the data display part judges the light polarization state according to the parameters, displays the light polarization state on the interface, draws a plane curve by using an X-Y chart, and calls a 3D Parametric Graph to realize the display of the Ponga ball as shown in the figure 11. And the data storage part uses a 'writing text file' component to timely store the measured data result and the calculated Stokes vector.

And under the condition of ensuring that the hardware connection is normal, pressing a Reset key to restart Arduino, clicking a 'motor switch' button on a LabVIEW front panel interface, and starting to run a program. It can be observed that the led lamp on Arduino is on. And when the progress bar reaches 100, the program is completely operated, the operating result stokes vector, the light polarization state, the ellipse graph, the bound sphere and the like can be displayed on the interface, and the stokes vector can be checked in a txt file for storing data, operated for many times and recorded for many times.

The above software part is only the application software example on the system of the utility model, and the specific algorithm of this software does not constitute right the utility model discloses the restriction of system can not influence yet the utility model discloses the implementation of system. Namely the utility model discloses the system as long as can pass through the deflection angle of the rotatory mirror holder of Arduino single chip microcomputer control to obtain different deflection angle's optical signal can. Further computational processing of the optical signals obtained with the system does not affect the basic functionality of the hardware system.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be considered as the protection scope of the present invention.

Claims (7)

1. A light polarization state detection system is characterized by comprising an optical system and a data acquisition system;

the optical system comprises a laser generator (1), a polaroid I (2), an 1/4 wave plate I (3), a 1/4 wave plate II (4), a polaroid II (5) and a light detector (6) which are sequentially arranged along the same optical axis, wherein the 1/4 wave plate II (4) is arranged on a rotating mirror bracket (9), the rotating mirror bracket (9) is arranged on an electric rotating platform, and the electric rotating platform is driven to rotate by a stepping motor (8);

the data acquisition system comprises a main control chip (7), a motor driver and a direct current power supply, wherein the main control chip (7) is connected with an upper computer, the motor driver and the main control chip (7) are powered by the direct current power supply, the input end of the motor driver is connected with the output end of the main control chip (7), and the output end of the motor driver is connected with a stepping motor (8); the output end of a photoelectric sensor in the optical detector (6) is connected with the input end of the main control chip (7).

2. A light polarization state detection system according to claim 1, wherein an amplifying and filtering circuit is arranged between the output end of the photoelectric sensor and the input end of the main control chip (7), and the amplifying and filtering circuit is powered by a direct current power supply through the power conversion module.

3. A light polarization state detection system according to claim 1, wherein the stepping motor (8) adopts a 2-phase stepping mode with a rotation angle of 1.8 °.

4. A light polarization state detection system according to claim 1, wherein the 1/4 wave plate two (4) has rotation angles of 0 °, 30 °, 45 ° and 60 °.

5. A light polarization state detection system according to claim 1, wherein the master control chip (7) is an Arduino single-chip microcomputer.

6. A light polarization state detection system of claim 1, wherein the motorized rotary stage is a PX-GD60 high precision motorized rotary stage.

7. The light polarization state detection system according to claim 1, wherein the upper computer connected with the main control chip (7) is a LabVIEW virtual instrument.

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