Michelson interference fringe automatic counter

Abstract

The utility model relates to the technical field of physical optical experiments, and discloses a Michelson interference fringe automatic counter, which comprises a laser light source, a Michelson interferometer and a photosensitive diode, the Michelson interferometer is fixedly installed, the laser light source is arranged at the light source input end of the Michelson interferometer, and the Michelson interferometer is arranged at the light source input end of the Michelson interferometer. A diode fixing frame is arranged at the annular pattern output position of the Michelson interferometer, an observation screen is arranged on the diode fixing frame, the observation screen is located at the annular pattern imaging position of the Michelson interferometer, a photosensitive diode is arranged on the diode fixing frame, the light receiving surface of the photosensitive diode is located at the position of the observation screen, and the light receiving surface of the photosensitive diode is located at the position of the observation screen. And the photosensitive diode converts the ring pattern of the Michelson interferometer into an electric signal and outputs the electric signal. According to the utility model, the number of interference ring patterns can be automatically counted, and a fast, accurate and fast metering method is provided for optical experiments.

Description

Technical Field

[0001] The utility model relates to the technical field of physical optics experiments, in particular to an automatic counter for Michelson interference fringes. Background Art

[0002] The Michelson interferometer has a wide range of applications in the fields of measuring the wavelength of light waves, the refractive index of media, and the change of micro-displacements. In the experiment of measuring the wavelength of He-Ne laser using the Michelson interferometer, it is necessary to count the throughput of hundreds of circular rings. Traditional visual counting is extremely prone to visual fatigue and thus generates errors. And during the experiment, other factors need to be considered, such as temperature, humidity, etc. It is necessary to monitor environmental variables while counting. Existing instruments mostly use single-chip microcomputers or CCD and other instruments for counting. The former has certain limitations in anti-interference and image processing capabilities, and the latter has a high cost and a complex program. Content of the Utility Model

[0003] The purpose of the utility model is to solve the above problems, and provide an automatic counter for Michelson interference fringes, which realizes the automatic counting of the number of interference fringes and provides a fast, accurate and rapid measurement method for optical experiments.

[0004] The technical solution adopted by the utility model is as follows:

[0005] An automatic counter for Michelson interference fringes, characterized in that it includes a laser light source, a Michelson interferometer and a photodiode. The Michelson interferometer is fixedly installed. The laser light source is arranged at the light source input end position of the Michelson interferometer. A fixing frame is arranged at the ring pattern output position of the Michelson interferometer. An observation screen is arranged on the fixing frame. The observation screen is located at the ring pattern imaging position of the Michelson interferometer. A photodiode is arranged on the fixing frame. The light receiving surface of the photodiode is located at the position of the observation screen. The photodiode converts the Michelson interferometer ring pattern into an electrical signal and outputs it.

[0006] Further, the fixing frame is a cylindrical structure, with a card slot in the middle. The observation screen is arranged in the card slot. A transverse plate in the diameter direction is arranged in front of the observation screen. A diode installation slot is arranged on the transverse plate. A round hole is arranged at the front end of the diode installation slot. The photodiode is arranged in the diode installation slot, and the photosensitive head of the photodiode extends out from the round hole to the position of the observation screen.

[0007] Further, the laser light source is a helium-neon laser.

[0008] Further, the photodiode is connected to a calculation and control unit. The calculation and control unit converts the electrical signal of the photodiode into a digital signal and calculates the number of changes in the ring pattern output by the Michelson interferometer.

[0009] Furthermore, the calculation and control unit is a Raspberry Pi, and the photosensitive diode is connected to the Raspberry Pi through Dupont wires.

[0010] Furthermore, the Raspberry Pi is connected to a computer monitor, and the computer monitor outputs the number of ring pattern changes.

[0011] The beneficial effects of the utility model are as follows:

[0012] (1) Through the photosensitive performance of the photosensitive diode, the changes and quantity of the ring patterns are quickly received;

[0013] (2) According to the signal output by the photosensitive diode, corresponding to the bright and dark fringes of the ring pattern, accurate counting is achieved;

[0014] (3) The structure is simple, the operation is convenient, and the calculation is accurate. Description of the Drawings

[0015] Att Figure 1 is a schematic diagram of the principle of the utility model;

[0016] Att Figure 2 is a schematic diagram of the structure of the photosensitive diode fixing bracket;

[0017] Att Figure 3 is a schematic diagram of the principle of photoelectric counting. Detailed Implementation Modes

[0018] The following will make a detailed description of the detailed implementation modes of the Michelson interference fringe automatic counter of the utility model with reference to the drawings.

[0019] Referring to Att Figure 1 , the Michelson interference fringe automatic counter includes a laser light source 1, a Michelson interferometer 2, and a photosensitive diode 3. The Michelson interferometer is fixedly installed, the laser light source is arranged at the light source input end position of the Michelson interferometer, a fixing bracket 5 is fixed at the ring pattern output position of the Michelson interferometer, an observation screen 4 is arranged on the diode fixing bracket, the observation screen 4 is located at the ring pattern imaging position of the Michelson interferometer, a photosensitive diode 3 is arranged on the fixing bracket 5, the light receiving surface of the photosensitive diode 3 is located at the position of the observation screen, and the photosensitive diode 3 converts the ring pattern of the Michelson interferometer into an electrical signal for output.

[0020] Referring to Att Figure 2 , the fixing bracket 5 is of a cylindrical structure, a clamping groove 6 is arranged in the middle, the observation screen 4 is arranged in the clamping groove 6, a transverse plate 7 in the diameter direction is arranged in front of the clamping groove 6, a diode installation groove 8 is arranged on the transverse plate 7, a round hole 9 is arranged at the front end of the diode installation groove 8, the diode installation groove 8 is used for fixedly installing the photosensitive diode 3, and when the photosensitive diode 3 is installed, the photosensitive head of the photosensitive diode 3 extends out from the round hole 9 to the position of the observation screen 4. The photoelectric conversion of the ring pattern on the observation screen is realized.

[0021] The photosensitive diode is connected to the calculation and control unit, which converts the electrical signal of the photosensitive diode into a digital signal and calculates the number of fringe changes output by the Michelson interferometer. Here, the Raspberry Pi is selected as the calculation and control unit, and the photosensitive diode is connected to the Raspberry Pi through Dupont wires. The Raspberry Pi is connected to a computer monitor, and the number of fringe changes is output on the computer monitor.

[0022] It should be noted that the signal output by the photosensitive diode is an analog signal. The Raspberry Pi of the calculation and control unit converts the analog signal into a digital signal and completes the counting through programming. The programming of the counting process is a common technology in the prior art, which is well-known to those of ordinary skill in the art and belongs to the prior art. In addition, the present patent protects the scheme of equipping a Michelson interferometer with a photosensitive diode for electronic counting, which belongs to the object protected by the utility model.

[0023] See the appendix Figure 3 , and cumulative counting is performed according to the change of the photoelectric signal of the photosensitive diode to complete the calculation of the interference fringes. The programming of this part is the prior art. The GPIO interface in the figure refers to the electrical signal interface for the photosensitive diode to transmit to the Raspberry Pi.

[0024] During the experiment, place the helium-neon laser and the Michelson interferometer on the test bench to ensure that the equipment is horizontal and at the same height. Wipe the plane of the interferometer clean so that the distances from the two reflectors to the beam splitter wedge are the same. Start the helium-neon laser and adjust the optical path so that the two beams of light meet on the observation screen. By adjusting the knob on the M2 mirror of the interferometer, make the center of the fringe circle align with the center of the ground glass of the observation screen, and the fringes are uniform and clear.

[0025] Place the photosensitive diode module with adjusted sensitivity on the diode fixing bracket, insert the photosensitive part into the central ring until it touches the display screen, and pass the Dupont wire at the tail through the round hole of the fixing bracket and connect it to the Raspberry Pi on the lower desktop. After completing the connection of the photoelectric conversion device, run the program of the Raspberry Pi, slowly rotate the fine focusing screw of the interferometer, and check the operation of the counting program. After everything is ready, record the number of fringe in-and-outs and the displacement of the plane mirror.

[0026] During the experiment, when adjusting the position of the plane mirror to change the optical path difference, it will cause the brightness change of the interference fringes. Utilizing the characteristic that the photosensitive diode module can detect the light intensity, the brightness change of the fringes is correspondingly output as high and low levels, and this electrical signal is used as the input signal of the Raspberry Pi. Then, through the pre-debugged program, the input electrical signal is converted into a digital signal to achieve the automatic counting function. Finally, the number of fringe changes is presented on the computer display screen.

[0027] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present utility model.

Claims

1. An automatic counter for Michelson interference fringes, characterized in that: It includes a laser light source, a Michelson interferometer and a photosensitive diode. The Michelson interferometer is fixedly installed. The laser light source is arranged at the light source input end position of the Michelson interferometer. A fixing frame is arranged at the ring pattern output position of the Michelson interferometer. An observation screen is arranged on the fixing frame. The observation screen is located at the ring pattern imaging position of the Michelson interferometer. A photosensitive diode is arranged on the fixing frame. The light receiving surface of the photosensitive diode is located at the position of the observation screen. The photosensitive diode converts the ring pattern of the Michelson interferometer into an electrical signal for output.

2. The Michelson interference fringe automatic counter according to claim 1, characterized in that: The fixing frame is of a cylindrical structure with a card slot in the middle. The observation screen is arranged in the card slot. A transverse plate in the diameter direction is arranged in front of the observation screen. A diode installation groove is arranged on the transverse plate. A round hole is arranged at the front end of the diode installation groove. The photosensitive diode is arranged in the diode installation groove. The photosensitive head of the photosensitive diode extends from the round hole to the position of the observation screen.

3. The Michelson interference fringe automatic counter according to claim 1, characterized in that: The laser light source is a helium-neon laser.

4. The Michelson interference fringe automatic counter according to any one of claims 1 to 3, characterized in that: The photosensitive diode is connected to a calculation and control unit. The calculation and control unit converts the electrical signal of the photosensitive diode into a digital signal and calculates the number of ring pattern changes output by the Michelson interferometer.

5. The Michelson interference fringe automatic counter according to claim 4, characterized in that: The calculation and control unit is a Raspberry Pi. The photosensitive diode is connected to the Raspberry Pi through a Dupont wire.

6. The Michelson interference fringe automatic counter according to claim 5, characterized in that: The Raspberry Pi is connected to a computer monitor. The computer monitor outputs the number of ring pattern changes.

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