Photoelectric hybrid bistable experimental device based on liquid crystal light intensity modulator

Abstract

The utility model belongs to the technical field of physics teaching equipment, and particularly relates to a photoelectric hybrid bistable experimental device based on a liquid crystal light intensity modulator. Comprising a laser, a liquid crystal light intensity modulator, a light intensity modulation circuit, a spectroscope, a reference light detector, a nonlinear optical element, an emergent light detector and a feedback circuit, a light beam emitted by a laser penetrates through a liquid crystal light intensity modulator to reach a spectroscope and then is divided into two beams, one beam irradiates a reference light detector, and the other beam penetrates through a nonlinear optical element to irradiate an emergent light detector; the liquid crystal light intensity modulator is controlled by a light intensity modulation circuit and monitored by a reference light detector; the light transmittance of the nonlinear optical element is related to the applied voltage; the emergent light detector detects the emergent light intensity of the nonlinear optical element, and the emergent light intensity is fed back to the nonlinear optical element after passing through the feedback circuit, so that the bistable effect is realized. According to the utility model, the relation between the voltage and the light transmittance can be effectively and visually displayed, the phenomenon of the photoelectric hybrid bistable effect is displayed, and the teaching effect is improved.

Description

Technical Field

[0001] This utility model belongs to the technical field of physics teaching equipment, specifically relating to a photoelectric hybrid bistable experimental device based on a liquid crystal light intensity modulator. Background Technology

[0002] For a given incident light intensity, there exist two possible, stable output light intensity states, and the reversal between these two stable states can be achieved optically; this phenomenon is called optical bistableness. The nonlinear optical element used in optoelectronic hybrid optical bistable systems has a transmittance that is related to the voltage applied to it. The outgoing light is converted into a voltage, amplified, and fed back to the nonlinear optical element, resulting in different transmittances for different outgoing light intensities. This creates two mutually constraining factors: transmittance depends on voltage, and voltage depends on transmittance, thus achieving optical bistableness. Using optical bistable devices as logic elements has promising applications. In physics experiments, to observe the bistable phenomenon, the incident light intensity needs to be modulated from low to high and from high to low, while simultaneously detecting the incident and outgoing light intensities of the nonlinear optical element. This invention designs a device that conveniently adjusts the beam intensity using the electric field voltage of a liquid crystal light intensity modulator. A beam splitter is placed in front of the nonlinear optical element to split a portion of the beam as a reference beam, the intensity of which is proportional to the intensity of the incident light of the nonlinear optical element. This device is easy to adjust and easy to observe, and its design is novel and has good teaching effect. Summary of the Invention

[0003] The purpose of this invention is to provide a novel, easy-to-use, and effective photoelectric hybrid bistable experimental device based on a liquid crystal light intensity modulator.

[0004] The photoelectric hybrid bistable experimental device based on a liquid crystal light intensity modulator provided by this utility model includes: a laser, a beam splitter, a liquid crystal light intensity modulator, a light intensity modulation circuit, a reference photodetector, a nonlinear optical element, an output photodetector, a light intensity modulation circuit, and a feedback circuit.

[0005] The laser, liquid crystal light intensity modulator, beam splitter, nonlinear optical element, and output photodetector are arranged sequentially; the light intensity modulation circuit is connected to the liquid crystal light intensity modulator; the reference photodetector is located on the other side of the beam splitter, such that the line connecting the distance from the reference photodetector to the beam splitter is perpendicular to the line connecting the distance from the liquid crystal light intensity modulator to the beam splitter; the feedback circuit is connected to both the nonlinear optical element and the output photodetector; wherein:

[0006] The laser emits a monochromatic beam that passes through a liquid crystal light intensity modulator to a beam splitter.

[0007] The beam splitter is at a 45° angle to the beam, splitting the monochromatic beam into reflected light and transmitted light. The reflected light is reflected by the beam splitter and illuminates the reference photodetector, while the transmitted light passes through the beam splitter, then through the nonlinear optical element, and illuminates the output photodetector.

[0008] The electric field strength of the liquid crystal light intensity modulator can be controlled and adjusted by the light intensity modulation circuit. It utilizes the principle that the orientation structure of liquid crystal molecules changes under an electric field to adjust the light intensity of the beam.

[0009] The reference photodetector is used to monitor the intensity of the light beam reflected by the beam splitter after passing through the liquid crystal light intensity modulator;

[0010] The transmittance of the nonlinear optical element is related to the voltage applied to it.

[0011] The emitted light detector is used to detect the emitted light intensity of the nonlinear optical element and transmit the light intensity signal to the digital feedback circuit via a cable.

[0012] The feedback circuit amplifies and modulates the light intensity signal and feeds it back to the nonlinear optical element, so that the nonlinear optical element has different transmittance under different emitted light intensities, thereby realizing a photoelectric hybrid bistable effect.

[0013] In use, this invention utilizes a light intensity modulation circuit to change the electric field on the liquid crystal light intensity modulator, causing the intensity of the light beam passing through the liquid crystal light intensity modulator to gradually increase and then decrease continuously. Simultaneously, the changes in the readings of the reference photodetector and the output photodetector are recorded. Finally, through simple calculation, the reading of the reference photodetector is converted into the incident light intensity of the nonlinear optical element and used as the abscissa, while the reading of the output photodetector is used as the ordinate, thus plotting a bistable curve and demonstrating the phenomenon of a photoelectric hybrid bistable effect.

[0014] This utility model has a novel design and is easy to use. It can effectively and intuitively display the relationship between voltage and transmittance, show the phenomenon of photoelectric hybrid bistable effect, and improve teaching effectiveness. Attached Figure Description

[0015] Figure 1 This is a top view of the structure of this utility model.

[0016] In the diagram, the numbers are as follows: 1 is the laser, 2 is the beam splitter, 3 is the liquid crystal light intensity modulator, 4 is the light intensity modulation circuit, 5 is the reference photodetector, 6 is the nonlinear optical element, 7 is the output photodetector, and 8 is the feedback circuit. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] This utility model includes: a laser 1, a beam splitter 2, a liquid crystal light intensity modulator 3, a light intensity modulation circuit 4, a reference photodetector 5, a nonlinear optical element 6, an output photodetector 7, and a feedback circuit 8.

[0019] The laser 1, liquid crystal light intensity modulator 3, beam splitter 2, nonlinear optical element 6, and output photodetector 7 are arranged sequentially. The light intensity modulation circuit 4 is connected to the liquid crystal light intensity modulator 3. The reference photodetector 5 is located on the other side of the beam splitter 2, such that the line connecting the reference photodetector 5 to the beam splitter 2 is perpendicular to the light path emitted by the laser 1. The beam splitter is at a 45° angle to the light path emitted by the laser 1. The feedback circuit 8 is connected to both the nonlinear optical element 6 and the output photodetector 7.

[0020] The laser 1 emits a monochromatic beam that passes through the liquid crystal light intensity modulator 3 to the beam splitter 2. The beam splitter 2 is at a 45° angle to the beam, splitting the beam into two beams. The reflected light illuminates the reference photodetector 5, and the transmitted light passes through the nonlinear optical element 6 and illuminates the output photodetector 7.

[0021] The liquid crystal light intensity modulator 3 uses the principle that the orientation structure of liquid crystal molecules changes under an electric field to adjust the light intensity of the beam emitted by the laser 1. The electric field of the liquid crystal light intensity modulator 3 comes from the light intensity modulation circuit 4, which is connected to the liquid crystal light intensity modulator 3 via a cable. The light intensity modulation circuit 4 has an adjustment knob for changing the electric field intensity on the liquid crystal light intensity modulator 3.

[0022] The reference photodetector 5 monitors the intensity of the light beam reflected by the beam splitter 2 after passing through the liquid crystal light intensity modulator 3 (i.e., as the reference light), and the unit is expressed in μW or mW. The intensity of the reference light is proportional to the intensity of the light transmitted through the beam splitter 2.

[0023] The transmittance of the nonlinear optical element 6 is related to the applied voltage. The outgoing photodetector 7 detects the outgoing light intensity of the nonlinear optical element, expressed in μW or mW. This light intensity signal is transmitted to the digital feedback circuit 8 via a cable. The feedback circuit 8 receives the outgoing light intensity signal detected by the outgoing photodetector 7, amplifies and modulates it, and then feeds it back to the nonlinear optical element 6. This allows the nonlinear optical element 6 to have different transmittances under different outgoing light intensities, thereby realizing a photoelectric hybrid bistable effect. The nonlinear optical element 6 can be an existing product, such as the BBO Pockel cell produced by Fujian Crystal Technology. The principle of this product is to use the change in polarization state of the electro-optic crystal when a voltage is applied, supplemented by a polarizer and an analyzer, to change its transmittance.

[0024] In use, this invention alters the electric field of the liquid crystal light intensity modulator by light intensity modulation, causing the intensity of the light beam passing through the liquid crystal light intensity modulator to gradually increase and then decrease continuously. Simultaneously, the changes in the readings of the reference photodetector and the output photodetector are recorded. Since the light intensity detected by the reference photodetector is proportional to the intensity of the light transmitted through the beam splitter, its reading can be converted into the incident light intensity of the nonlinear optical element through simple calculations. By plotting the incident light intensity of the nonlinear optical element on the x-axis and the reading of the output photodetector on the y-axis, a bistable curve can be plotted, thus demonstrating the phenomenon of a photoelectric hybrid bistable effect and achieving experimental or teaching objectives.

[0025] Although the above methods are illustrated and described as a series of structures for the sake of simplicity, it should be understood and appreciated that these methods are not specifically limited, as some structures may occur in different orders and / or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0026] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hybrid opto-electric bistable experimental device based on liquid crystal light intensity modulator; characterized in that, The application relates to a laser, a beamsplitter, a liquid crystal light intensity modulator, a light intensity modulation circuit, a reference light detector, a nonlinear optical element, an emergent light detector, a light intensity modulation circuit and a feedback circuit. The laser, the liquid crystal light intensity modulator, the beamsplitter, the nonlinear optical element and the emergent light detector are sequentially arranged; the light intensity modulation circuit and the liquid crystal light intensity modulator are connected; the reference light detector is arranged on the other side of the beamsplitter, so that the distance line from the reference light detector to the beamsplitter is perpendicular to the distance line from the liquid crystal light intensity modulator to the beamsplitter; the feedback circuit is connected with the nonlinear optical element and the emergent light detector respectively; wherein: The laser emits a monochromatic light beam which passes through the liquid crystal light intensity modulator and the beamsplitter; The beamsplitter is at a 45-degree angle with the light beam, and divides the monochromatic light beam into reflected light and transmitted light; the reflected light is reflected by the beamsplitter and irradiates the reference light detector; the transmitted light passes through the beamsplitter and then the nonlinear optical element and irradiates the emergent light detector; The electric field intensity of the liquid crystal light intensity modulator can be controlled and adjusted by the light intensity modulation circuit, and the light intensity of the light beam is adjusted by the principle that the orientation structure of liquid crystal molecules changes under the electric field; The reference light detector is used for monitoring the intensity of the light beam which passes through the liquid crystal light intensity modulator and is reflected by the beamsplitter; The nonlinear optical element has a transmittance related to the voltage applied thereto; The emergent light detector is used for detecting the emergent light intensity of the nonlinear optical element and transmitting the light intensity signal to the digital feedback circuit through a cable; The feedback circuit amplifies and modulates the light intensity signal and then feeds it back to the nonlinear optical element, so that the nonlinear optical element has different transmittances under different emergent light intensities, thereby realizing the optoelectronic hybrid bistable effect. ​

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