Device and method for identifying and measuring Fraunhofer multi-slit diffraction phenomenon

Abstract

The invention discloses a Fraunhofer multi-slit diffraction phenomenon identification and measurement device and an identification and measurement method, particularly relates to the technical field of optical measurement, and solves the problems that in the prior art, a traditional light intensity distribution measurement method depends on manual recording of data points and analysis and drawing, the required light intensity value is obtained from the reading of a digital galvanometer, and the measurement accuracy is low. And the value jump is fast and inaccurate. According to the technical scheme, a real-time diffraction pattern is automatically converted and processed into relative light intensity distribution, data selection is automatically carried out, and relevant parameters such as the single-slit width and the multi-slit grating constant are measured and calculated and displayed through a multi-mode experiment interaction interface; according to the invention, the precision is improved, the error is reduced, the operation is simple and convenient, the digitization, visualization and modernization of the traditional single-slit diffraction experiment are realized, and the multi-slit diffraction phenomenon can be further explored.

Description

Technical Field

[0001] The invention relates to the technical field of optical measurement, and in particular to an identification and measurement device and an identification and measurement method for Fraunhofer multi-slit diffraction phenomenon. Background Art

[0002] The diffraction phenomenon of light is a manifestation of the wave nature of light. Single-slit diffraction is generally divided into Fresnel diffraction and Fraunhofer diffraction. In Fraunhofer diffraction, the distance between the single slit and the observation screen is infinite or equivalent to infinity, that is, the incident wave and the diffracted wave can be regarded as plane waves. In a broad sense, diffraction screens with periodic spatial structures or optical properties are collectively called gratings. From single-slit diffraction to multi-slit diffraction, its essence is the simple addition of complex interference amplitudes. Exploring the diffraction phenomenon and light intensity distribution provides students with a case from theory to practice, so it is one of the must-do experiments in basic physics education in various universities.

[0003] However, the traditional method of measuring light intensity distribution relies on manually recording data points and analyzing and plotting them. The required light intensity value is obtained from the reading of the digital galvanometer, and its value jumps quickly and is inaccurate. At the same time, the experiment requires manual control of the rotation distance, which is difficult to control and the process is relatively cumbersome, resulting in large errors in the final light intensity distribution curve and parameter values ​​such as the slit width, and the ideal experimental effect cannot be achieved. Summary of the invention

[0004] Therefore, the present invention solves the problem that the traditional light intensity distribution measurement method in the prior art relies on manually recording data points and analyzing and drawing. The required light intensity value is obtained from the reading of the digital galvanometer, and its value jumps quickly and is inaccurate. At the same time, the rotation distance needs to be manually controlled in the experiment, which is not easy to control, and the process is also cumbersome, resulting in a large error between the final light intensity distribution curve and the parameter values ​​such as the slit width, and the ideal experimental effect cannot be achieved. The identification and measurement device and identification and measurement method for the Fraunhofer multi-slit diffraction phenomenon provided by the present invention realize the improvement of the optical path, digital galvanometer, etc., develop a light intensity distribution measurement system based on image recognition, automatically convert the real-time diffraction pattern into a relative light intensity distribution, and automatically select data, calculate the single-slit slit width, multi-slit grating constant and other related parameters, and display them using a multi-mode experimental interactive interface, so as to improve accuracy, reduce errors, and simplify operation to meet modern teaching needs. The traditional single-slit diffraction experiment is digitized, visualized and modernized, and the multi-slit diffraction phenomenon can be further explored.

[0005] The present invention provides an identification and measurement device for Fraunhofer multi-slit diffraction phenomenon, comprising an industrial camera, a second convex lens, a grating frame and a combined grating sheet, a first convex lens and a semiconductor laser arranged in sequence on an optical bench; the data output end of the industrial camera is connected to the data receiving end of the identification and measurement main system. The industrial camera can be a CMOS camera.

[0006] Furthermore, the identification and measurement main system includes an industrial camera calling and image processing module, a single-slit diffraction automatic data selection and measurement system, a multi-slit diffraction automatic data selection and measurement system, and a multi-mode diffraction identification system interface.

[0007] Furthermore, the identification and measurement main system is arranged in a computer; the data output terminal of the industrial camera is connected to the data receiving terminal of the computer, and the computer transmits the received data to the identification and measurement main system.

[0008] Furthermore, the grating frame and the combined grating sheet are in close contact with the second convex lens; the distance from the first convex lens to the semiconductor laser and the distance from the second convex lens to the center of the industrial camera are the focal lengths of the convex lenses.

[0009] The present invention also provides an identification and measurement method based on the above identification and measurement device for the Fraunhofer multi-slit diffraction phenomenon, comprising the following steps:

[0010] S1: Place the industrial camera, the second convex lens, the grating frame and the combined grating sheet, the first convex lens and the semiconductor laser on the optical bench in sequence; before placing them, use a pinhole diaphragm to place them on the output light path of the semiconductor laser, and adjust the output beam of the laser so that it becomes a uniform parallel beam after passing through the pinhole; then place the experimental instruments in sequence, and fine-tune the position and angle of the pinhole diaphragm to ensure that the center of the beam is completely aligned with the optical axis; at the same time, the experimental ambient light is in a relatively dark state;

[0011] S2: Connect the industrial camera to the computer via the USB interface to achieve correct recognition and calling of the camera;

[0012] S3: The semiconductor laser emits a light beam, which is irradiated onto the camera head of the industrial camera after passing through the first convex lens and the second convex lens. The industrial camera transmits the received image to the computer;

[0013] S4: The industrial camera calls and image processing module converts the image from BGR format to RGB format. In addition, the image is converted from OpenCV format to PIL format. In order to enhance the visualization effect of the image, the real-time image captured by the camera is fine-tuned clockwise or counterclockwise to obtain a more accurate diffraction pattern. The interface knob is used for rotation. Each knob corresponds to the function of adjusting the image clockwise or counterclockwise. The relevant image rotation function of the Opencv RotatedRect class is called to update the display angle of the image. The image is resized and cropped. Combined with the Tkinter graphical interface, the image is collected and processed in real time to provide an input light intensity data source.

[0014] S5: Select between “single slit” and “multiple slit” modes through the multi-mode diffraction recognition system interface;

[0015] S6: When the "single slit" mode is selected, the single slit diffraction automatic data selection and measurement system performs Gaussian filtering and moving average processing on the light intensity data to smooth the signal and reduce noise; then, the positions of the corresponding troughs and peaks are detected on both sides of the main peak position of the data; the average distance between adjacent troughs is calculated using the relative position of the troughs and converted into actual spatial distance; after inputting the known distance from the light source to the camera, the diffraction angle is automatically calculated, and then the wavelength of the laser is input, and the slit width of the single slit is automatically calculated in combination with the diffraction angle; finally, the measured value is output on the interface, and the positions of the troughs and peaks are marked on the relative light intensity distribution diagram to assist analysis and debugging;

[0016] S7: When the "multi-slit" mode is selected, the multi-slit diffraction automatic data selection and measurement system searches for peaks in the smoothed light intensity data, and records the positions of all peaks and their corresponding light intensity values; determines the position of the maximum peak and the second highest peaks on its left and right sides, marking them as the highest peak on the left and the highest peak on the right, respectively; manually moves the two-dimensional adjustable frame where the camera is located, observes the missing level phenomenon of the multi-slit diffraction and records the position of the missing level; after inputting the laser wavelength, lens focal length and number of missing levels, the system calculates the spacing (x) between the identified peaks, combines the laser wavelength, lens focal length and number of missing levels, and further calculates the grating constant (d), slit width (a) and slit distance (b), and displays them in real time on the user interface; if not enough peaks are found, a prompt message will be output to inform the user that the calculation cannot be performed.

[0017] Furthermore, the correct identification and calling of the industrial camera in step S2 includes opening the video stream, reading frame data and releasing the video device; and detecting the connection status of the camera. If the camera fails to open, a prompt message is thrown to prompt the user to check the hardware connection.

[0018] Furthermore, during the detection process of step S6, the camera gain and exposure parameters are adjusted to ensure that significant troughs and peaks are identified.

[0019] Furthermore, the idea of ​​implementing the multi-mode diffraction identification system interface in step S5 is to build an application based on Tkinter to provide an interface for optical diffraction calculations, set the basic properties and layout of the application during initialization, and create multiple window components and functional modules, allowing users to choose between "single slit" and "multi-slit" modes, and each mode has a special input window for users to input parameters, and then trigger the calculation function through a button, and the calculation results will be displayed in real time in the graphics window.

[0020] In the above technical solution, the technical effects and advantages provided by the present invention are:

[0021] 1. The identification and measurement device and identification and measurement method of the Fraunhofer multi-slit diffraction phenomenon provided by the present invention develops a light intensity distribution measurement system based on image recognition, automatically converts the real-time diffraction pattern into relative light intensity distribution, and automatically selects data, calculates the single-slit slit width, multi-slit grating constant and other related parameters, and displays them using a multi-mode experimental interactive interface, thereby achieving improved accuracy, reduced errors, simple operation, and meeting modern teaching needs. The traditional single-slit diffraction experiment is digitized, visualized and modernized, and the multi-slit diffraction phenomenon can be further explored.

[0022] 2. The present invention provides an identification and measurement device and identification and measurement method for the Fraunhofer multi-slit diffraction phenomenon. The user selects single-slit or multi-slit mode in the Fraunhofer diffraction identification system interface, inputs the laser wavelength, focal length and number of missing orders, and the device automatically generates a diffraction relative light intensity distribution diagram and calculates relevant information such as the slit width and grating constant. The measurement result has an error of 1.2%-3.5% compared with the theoretical value; and the measurement time is optimized by more than 10 times compared with the original experimental device.

[0023] 3. The identification and measurement device and identification and measurement method for the Fraunhofer multi-slit diffraction phenomenon provided by the present invention, through the industrial camera on the optical stand, the second convex lens, the grating frame and the combined grating plate, the first convex lens and the semiconductor laser and the identification and measurement main system composed of the device for identifying and measuring the Fraunhofer multi-slit diffraction phenomenon, can allow the user to select the single slit or multi-slit mode in the Fraunhofer diffraction identification system interface, input the laser wavelength, focal length and the number of missing orders, and the device will automatically generate the diffraction relative light intensity distribution diagram and calculate the slit width, grating constant and other related information; the incident light beam emitted by the light source is focused and adjusted by a pair of convex lenses so that it hits the camera receiving module in parallel and with higher intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic diagram of the overall structure of the identification and measurement device for the Fraunhofer multi-slit diffraction phenomenon of the present invention;

[0026] Figure 2 The present invention uses the original experimental instrument to measure and hand-draw the relative light intensity distribution curve;

[0027] Figure 3 The interface diagram of the single slit width measured by the present invention is 0.10 mm in theoretical value;

[0028] Figure 4The interface diagram of the single slit width measured by the present invention is 0.12 mm in theoretical value;

[0029] Figure 5 The interface diagram of the theoretical value of the multi-slit grating constant measured by the present invention is 0.20 mm;

[0030] Figure 6 This is a front view of the actual object of the test of the present invention;

[0031] Figure 7 This is a top view of the actual object of the test of the present invention.

[0032] Description of reference numerals:

[0033] 1. Industrial camera; 2. Second convex lens; 3. Grating frame and combined grating plate; 4. First convex lens; 5. Semiconductor laser. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] Embodiment 1:

[0036] The present embodiment provides an identification and measurement device for the Fraunhofer multi-slit diffraction phenomenon, comprising an industrial camera 1, a second convex lens 2, a grating frame and a combined grating plate 3, a first convex lens 4 and a semiconductor laser 5, which are sequentially arranged on an optical stand; the data output end of the industrial camera 1 is connected to the data receiving end of the identification and measurement main system, the identification and measurement main system comprises an industrial camera 1 calling and image processing module, a single-slit diffraction automatic data selection and measurement system, a multi-slit diffraction automatic data selection and measurement system and a multi-mode diffraction identification system interface, and the identification and measurement main system is installed in a computer; the data output end of the industrial camera 1 is connected to the data receiving end of the computer, and the computer transmits the received data to the identification and measurement main system, i.e., the system main program.

[0037] The identification and measurement device for the Fraunhofer multi-slit diffraction phenomenon is composed of an industrial camera 1, a second convex lens 2, a grating frame and a combined grating sheet 3, a first convex lens 4, a semiconductor laser 5, and an identification and measurement main system on the optical bench. The user can select a single slit or multi-slit mode in the Fraunhofer diffraction identification system interface, input the laser wavelength, focal length, and missing order, and the device will automatically generate a diffraction relative light intensity distribution diagram and calculate relevant information such as the slit width and grating constant. The incident light beam emitted by the light source is focused and adjusted through a pair of convex lenses so that it hits the camera receiving module in parallel and with higher intensity.

[0038] In this embodiment, the grating frame and the combined grating sheet 3 are in close contact with the second convex lens 2; the distance from the first convex lens 4 to the semiconductor laser 5 and the distance from the second convex lens 2 to the center of the industrial camera 1 are the focal lengths of the convex lenses.

[0039] Embodiment 2:

[0040] This embodiment provides a chip heat dissipation method based on the novel three-dimensional packaging structure based on the flexible substrate, characterized in that it includes the following steps:

[0041] The identification and measurement method based on the above identification and measurement device for the Fraunhofer multi-slit diffraction phenomenon includes the following steps:

[0042] S1: Place the industrial camera 1, the second convex lens 2, the grating frame and the combined grating sheet 3, the first convex lens 4 and the semiconductor laser 5 on the optical bench in sequence; place the experimental device on the optical bench in sequence according to the actual optical path and fix it; the distance from the first convex lens 4 to the laser is the focal length of the convex lens 150mm, the grating sheet is close to the second convex lens 2, and the distance from the second convex lens 2 to the center of the camera is also the focal length of the convex lens 150mm. Connect the camera to the computer through the USB interface and equip it with the relevant environmental package;

[0043] S2: Connect the industrial camera 1 to the computer via the USB interface to achieve correct recognition and calling of the camera;

[0044] S3: The semiconductor laser 5 emits a light beam, which is irradiated onto the camera head of the industrial camera 1 after passing through the first convex lens 4 and the second convex lens 2. The industrial camera 1 transmits the received image to the computer;

[0045] S4: The industrial camera 1 calls the image processing module to convert the image from BGR format to RGB format. In addition, the image is converted from OpenCV format to PIL format. At the same time, the real-time image captured by the camera is fine-tuned clockwise or counterclockwise to obtain a more accurate diffraction pattern. The image is resized and cropped, and combined with the Tkinter graphical interface, the image is collected and processed in real time to provide an input light intensity data source.

[0046] S5: Select between “single slit” and “multiple slit” modes through the multi-mode diffraction recognition system interface;

[0047] S6: When the "single slit" mode is selected, the single slit diffraction automatic data selection and measurement system performs Gaussian filtering and moving average processing on the light intensity data to smooth the signal and reduce noise; then, the positions of the corresponding troughs and peaks are detected on both sides of the main peak position of the data; the average distance between adjacent troughs is calculated using the relative position of the troughs and converted into actual spatial distance; after inputting the known distance from the light source to the camera, the diffraction angle is automatically calculated, and then the wavelength of the laser is input, and the slit width of the single slit is automatically calculated in combination with the diffraction angle; finally, the measured value is output on the interface, and the positions of the troughs and peaks are marked on the relative light intensity distribution diagram to assist analysis and debugging;

[0048] S7: When the "multi-slit" mode is selected, the multi-slit diffraction automatic data selection and measurement system searches for peaks in the smoothed light intensity data, and records the positions of all peaks and their corresponding light intensity values; determines the maximum peak and the positions of the second highest peaks on its left and right sides, marking them as the highest peak on the left and the highest peak on the right, respectively; manually moves the two-dimensional adjustable frame where the camera is located, observes the missing level phenomenon of the multi-slit diffraction and records the position of the missing level; after inputting the laser wavelength, lens focal length and number of missing levels, the system further calculates the grating constant (d), slit width (a) and slit distance (b) by calculating the spacing (x) between the identified peaks, and displays them in real time on the user interface; if not enough peaks are found, a prompt message will be output to inform the user that the calculation cannot be performed.

[0049] In this embodiment, the correct identification and calling of the industrial camera 1 in step S2 includes opening the video stream, reading frame data and releasing the video device; and detecting the connection status of the camera. If the camera fails to open, a prompt message is thrown to prompt the user to check the hardware connection.

[0050] In this embodiment, during the detection process of step S6, the camera gain and exposure parameters are adjusted to ensure that significant troughs and peaks are identified.

[0051] In this embodiment, the idea of ​​implementing the multi-mode diffraction identification system interface in step S5 is to build an application based on Tkinter to provide an interface for optical diffraction calculations, set the basic properties and layout of the application during initialization, and create multiple window components and functional modules, allowing users to choose between "single slit" and "multi-slit" modes. Each mode has a special input window for users to input parameters, and then trigger the calculation function through a button, and the calculation results will be displayed in real time in the graphics window.

[0052] The following is a comparison between the measurement results of the original experimental instrument and the measurement results of the present invention;

[0053] Results obtained from the original test equipment test:

[0054]

[0055]

[0056] Get as Figure 2 The hand-drawn relative light intensity distribution curve shown: The experimental measurement results of the present invention:

[0057] Test Group 1:

[0058]

[0059] Test Group 2:

[0060]

[0061] Test Group 3:

[0062]

[0063]

[0064] By taking the average of the data from multiple measurements and using the relative error formula: (theoretical value - measured value) / theoretical value, the error can be calculated, and the laser wavelength is 632.8nm. Using the original experimental instrument for measurement, in the case of a single slit, the specific value of the slit width a is calculated from the multi-level fringe data and the average is about 0.078mm. Compared with the theoretical value, the error is about 11.43%, and the relative light intensity distribution curve made according to the relative position and the photocurrent value is quite different from the theoretical image. It can be seen from the detection groups one and two that the errors are 1.3% and 1.9% respectively, a decrease of nearly 10%. In the case of multiple slits, the error of the grating constant d measured multiple times is about 2.1% compared with the theoretical value, with high accuracy, and the lowest error reaches about 0.33%.

[0065] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A device for identifying and measuring Fraunhofer multi-slit diffraction phenomenon, characterized in that: It comprises an industrial camera (1), a second convex lens (2), a grating frame and a combined grating sheet (3), a first convex lens (4) and a semiconductor laser (5) which are sequentially arranged on an optical bench; the data output end of the industrial camera (1) is connected to the data receiving end of the identification and measurement main system.

2. The device for identifying and measuring the Fraunhofer multi-slit diffraction phenomenon according to claim 1, characterized in that: The identification and measurement main system comprises an industrial camera (1) calling and image processing module, a single-slit diffraction automatic data selection and measurement system, a multi-slit diffraction automatic data selection and measurement system, and a multi-mode diffraction identification system interface.

3. The device for identifying and measuring the Fraunhofer multi-slit diffraction phenomenon according to claim 2, characterized in that: The data output end of the industrial camera (1) is connected to the data receiving end of the computer, and the computer transmits the received data to the identification and measurement main system.

4. The device for identifying and measuring the Fraunhofer multi-slit diffraction phenomenon according to claim 3, characterized in that: The grating frame and the combined grating sheet (3) are in close contact with the second convex lens (2); the distance from the first convex lens (4) to the semiconductor laser (5) and the distance from the second convex lens (2) to the center of the industrial camera (1) are the focal lengths of the convex lenses.

5. An identification and measurement method for the Fraunhofer multi-slit diffraction phenomenon based on the identification and measurement device according to any one of claims 1 to 4, characterized in that: The steps include: S1: placing an industrial camera (1), a second convex lens (2), a grating frame and a combined grating sheet (3), a first convex lens (4) and a semiconductor laser (5) in sequence on an optical bench; S2: Connect the industrial camera (1) to the computer via a USB interface to achieve correct recognition and calling of the camera; S3: The semiconductor laser (5) emits a light beam, which passes through the first convex lens (4) and the second convex lens (2) and then irradiates the camera head of the industrial camera (1). The industrial camera (1) transmits the received image to the computer; S4: Industrial camera (1) calls the image processing module to convert the image from BGR format to RGB format. In addition, the image is converted from OpenCV format to PIL format. At the same time, the real-time image captured by the camera is fine-tuned clockwise or counterclockwise to obtain a more accurate diffraction pattern. The image is resized and cropped. Combined with the Tkinter graphical interface, the image is collected and processed in real time to provide an input light intensity data source. S5: Select between "Single Slit" and "Multiple Slits" modes through the Multi-Mode Diffraction Recognition System interface; S6: When the "single slit" mode is selected, the single slit diffraction automatic data selection and measurement system performs Gaussian filtering and moving average processing on the light intensity data to smooth the signal and reduce noise; then, the corresponding troughs and peaks are detected on both sides of the main peak position of the data; the average distance between adjacent troughs is calculated using the relative position of the troughs and converted into actual spatial distance; after inputting the known distance from the light source to the camera, the diffraction angle is automatically calculated, and then the wavelength of the laser is input, and the slit width of the single slit is automatically calculated in combination with the diffraction angle; finally, the measured value is output on the interface, and the positions of the troughs and peaks are marked on the relative light intensity distribution diagram to assist analysis and debugging; S7: When the "multi-slit" mode is selected, the multi-slit diffraction automatic data selection and measurement system searches for peaks in the smoothed light intensity data and records the positions of all peaks and their corresponding light intensity values; Determine the maximum peak and the positions of the second highest peaks on its left and right sides, marking them as the highest peak on the left and the highest peak on the right respectively; manually move the two-dimensional adjustable frame where the camera is located, observe the missing level phenomenon of multi-slit diffraction and record the missing level position; after inputting the laser wavelength, lens focal length and number of missing levels, the system further calculates the grating constant (d), slit width (a) and slit distance (b) by calculating the spacing (x) between the identified peaks, and displays them in real time on the user interface; If not enough peaks are found, a prompt message will be output to inform the user that the calculation cannot be performed.

6. The identification and measurement method according to claim 5, characterized in that: The correct identification and calling of the industrial camera (1) in step S2 includes opening the video stream, reading frame data and releasing the video device; and detecting the connection status of the camera. If the camera fails to be opened, a prompt message is thrown to prompt the user to check the hardware connection.

7. The identification and measurement method according to claim 5, characterized in that: During the detection process of step S6, the camera gain and exposure parameters are adjusted to ensure that significant troughs and peaks are identified.

8. The identification and measurement method according to claim 5, characterized in that: The idea of ​​implementing the multi-mode diffraction identification system interface in step S5 is to build an application based on Tkinter to provide an interface for optical diffraction calculation, set the basic properties and layout of the application during initialization, create multiple window components and functional modules, allow users to choose between "single slit" and "multi-slit" modes, and each mode has a special input window for users to input parameters. The calculation function is then triggered by a button, and the calculation results will be displayed in real time in the graphics window.

9. The identification and measurement method according to claim 5, characterized in that: In step S4, the image is converted from BGR format to RGB format using the cv2.cvtColor function.

10. The identification and measurement method according to claim 5, characterized in that: In step S7, the find_peaks function is used to detect peaks in the one-dimensional array.

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