Light source for generating circularly polarized laser and detection device thereof

Abstract

The invention provides a light source for generating circularly polarized laser and a detection device thereof, and relates to the technical field of lasers. The light source for generating the circularly polarized laser comprises a pump laser and an optical resonant cavity which takes a chiral quasi-two-dimensional perovskite thin film as an optical gain medium, the pump laser is used for generating pump light, controlling the pump light to vertically enter the optical resonant cavity, and focusing the pump light on the chiral quasi-two-dimensional perovskite thin film; and the chiral quasi-two-dimensional perovskite thin film is used for generating stimulated radiation under the action of the pump light and the optical resonant cavity to generate circularly polarized laser. The polarization degree of the circular polarization laser can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of laser technology, and more particularly, to a light source for generating circularly polarized laser light and a detection device thereof. Background Art

[0002] Circularly polarized lasers have important applications in 3D display and imaging, information storage, spin electronics, quantum computing, and information anti-counterfeiting. In the field of optics, obtaining circularly polarized lasers often requires the use of optical components. For example, the commonly used optical components for converting unpolarized light into circularly polarized laser output are polarizers and quarter-wave plates. Their working principle can be seen as filtering out the desired linearly polarized light from the incident light and then converting it into circularly polarized laser light. The circularly polarized laser light obtained in this way has a high energy loss, and the intensity of the output light is lower than that of the incident light. Summary of the Invention

[0003] In view of this, the present disclosure provides a light source for generating circularly polarized laser light and a detection device thereof.

[0004] One aspect of the present disclosure provides a light source for generating circularly polarized laser light, comprising: a pump laser and an optical resonant cavity with a chiral quasi-two-dimensional perovskite film as an optical gain medium; the pump laser is used to generate pump light, control the pump light to be vertically incident on the optical resonant cavity, and focus the pump light on the chiral quasi-two-dimensional perovskite film; the chiral quasi-two-dimensional perovskite film is used to generate stimulated radiation under the action of the pump light and the optical resonant cavity, thereby generating circularly polarized laser light.

[0005] According to an embodiment of the present disclosure, the optical resonant cavity further includes two distributed Bragg reflectors arranged relatively parallel to each other; the chiral quasi-two-dimensional perovskite film is arranged between the two distributed Bragg reflectors.

[0006] According to an embodiment of the present disclosure, the pump laser includes a femtosecond laser, a lens, and a first linear polarizer; the femtosecond laser is used to emit a first laser; the lens is used to converge the first laser to obtain a second laser; the first linear polarizer is used to convert the second laser into linearly polarized light to obtain the pump light.

[0007] According to an embodiment of the present disclosure, the chiral quasi-two-dimensional perovskite film is coated on one of the opposite surfaces of the two distributed Bragg reflectors.

[0008] According to an embodiment of the present disclosure, the chiral ligand of the chiral quasi-two-dimensional perovskite is , perovskite is .

[0009] According to an embodiment of the present disclosure, the wavelength of the pump light is in the range of 380 nm to 490 nm.

[0010] According to an embodiment of the present disclosure, the energy density of the pump light is greater than or equal to 130 μJ / cm².

[0011] According to an embodiment of the present disclosure, one of the two distributed Bragg reflectors is an output mirror; the two distributed Bragg reflectors include a first distributed Bragg reflector and a second distributed Bragg reflector; the optical resonant cavity is used to control circularly polarized photons to reflect back and forth between the two distributed Bragg reflectors of the optical resonant cavity, and induce stimulated radiation each time the photons pass through the chiral quasi-two-dimensional perovskite film, thereby generating circularly polarized laser light, and emitting the circularly polarized laser light from the output mirror; wherein the circularly polarized photons are obtained by radiating spin-polarized carriers generated by the chiral quasi-two-dimensional perovskite film under the action of the pump light.

[0012] Another aspect of the present disclosure provides a detection device for the above-mentioned light source that generates circularly polarized laser light, comprising: a quarter-wave plate, a second linear polarizer, a lens combination and an optical fiber collector; the above-mentioned light source that generates circularly polarized laser light is used to emit the circularly polarized laser light to be detected, and control the above-mentioned circularly polarized laser light to be vertically incident on the above-mentioned quarter-wave plate; the above-mentioned circularly polarized laser light to be detected includes left-handed circularly polarized light and right-handed circularly polarized light; the above-mentioned quarter-wave plate is used to convert the above-mentioned left-handed circularly polarized light into a first linear polarized light, and convert the above-mentioned right-handed circularly polarized light into a second linear polarized light, and control the above-mentioned first linear polarized light and the above-mentioned second linear polarized light to be vertically incident on the above-mentioned second linear polarizer; the above-mentioned second linear polarizer is used to emit the linear polarization of the above-mentioned first linear polarizer and the above-mentioned second linear polarizer that is parallel to the transmission direction of the above-mentioned second linear polarizer to obtain a third linear polarized light; the above-mentioned lens combination is used to focus the above-mentioned third linear polarized light onto the receiving end of the above-mentioned optical fiber collector.

[0013] According to an embodiment of the present disclosure, the lens combination includes a first convex lens and a second convex lens; the first convex lens is used to convert the polarized light emitted from the second linear polarizer into parallel light; the second convex lens is used to focus the parallel light to the receiving end of the optical fiber collector.

[0014] According to an embodiment of the present disclosure, the pump light generated by the pump laser is vertically incident on the optical resonant cavity and focused on the chiral quasi-two-dimensional perovskite film, so that the chiral quasi-two-dimensional perovskite film generates circularly polarized photons. The circularly polarized photons resonate in the optical resonant cavity and induce stimulated radiation each time they pass through the chiral quasi-two-dimensional perovskite film, thereby obtaining circularly polarized laser light. Since the circularly polarized photons generated by the chiral quasi-two-dimensional perovskite film resonate in the optical resonant cavity, the light intensity and polarization degree of the circularly polarized laser light are increased. In addition, the polarization degree of the circularly polarized laser light is controlled by the chirality of the chiral quasi-two-dimensional perovskite film to obtain a circularly polarized laser light with a higher polarization degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0016] Figure 1 The structure of a light source for generating circularly polarized laser light according to an embodiment of the present disclosure is schematically shown;

[0017] Figure 2 The following schematically shows a structural diagram of a detection device for a light source generating circularly polarized laser light according to another embodiment of the present disclosure;

[0018] Figure 3 A flowchart schematically illustrates a method for designing a light source for generating circularly polarized laser light according to an embodiment of the present disclosure;

[0019] Figure 4 A schematic diagram illustrating a device structure of a design process for a light source for generating circularly polarized laser light according to an embodiment of the present disclosure;

[0020] Figure 5 A schematic diagram showing the principle of a vertical cavity surface emitting laser cavity amplifying the circular polarization of light emitted by a chiral material;

[0021] Figure 6 A diagram schematically showing test results of circular polarization of laser light emitted by a vertical cavity surface emitting circularly polarized laser; and

[0022] Figure 7 The diagram schematically shows the threshold test diagram of laser generation by a vertical cavity surface emitting circularly polarized laser. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0024] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0025] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0026] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0027] In the embodiments of this disclosure, the collection, updating, analysis, processing, use, transmission, provision, disclosure, and storage of all data involved (including, but not limited to, user personal information) comply with relevant laws and regulations, are used for legitimate purposes, and do not violate public order and good morals. In particular, necessary measures have been taken to prevent unauthorized access to user personal information and maintain the security of user personal information and network security.

[0028] In the embodiments of the present disclosure, the user's authorization or consent is obtained before obtaining or collecting the user's personal information.

[0029] Circularly polarized light has important applications in 3D display and imaging, information storage, spintronics, quantum computing, and information anti-counterfeiting. In the field of optics, obtaining circularly polarized light often requires the use of optical components or liquid crystal materials, which significantly reduces optical efficiency. Researching light sources that directly emit circularly polarized light is one approach to solving this problem.

[0030] Typically, the commonly used optical components for converting unpolarized light into circularly polarized light output are polarizers and quarter-wave plates. Their operating principle can be seen as filtering out the desired linearly polarized light from the incident light and then converting it into circularly polarized light. Therefore, the intensity of the outgoing light is generally much lower than the incident light, which is unsatisfactory from an energy efficiency perspective and also presents intractable difficulties in integration. Methods such as using liquid crystal materials to filter and generate circularly polarized light also face similar issues. To address this issue, light sources that directly generate circularly polarized light have been studied. Although introducing chirality into perovskites can achieve circularly polarized luminescence to a certain extent, the problem of low polarization still exists.

[0031] Embodiments of the present disclosure provide a light source for generating circularly polarized laser light and a detection device thereof.

[0032] According to an embodiment of the present disclosure, a light source for generating circularly polarized laser light includes: a pump laser and an optical resonant cavity with a chiral quasi-two-dimensional perovskite film as an optical gain medium; the pump laser is used to generate pump light, control the pump light to be vertically incident on the optical resonant cavity, and focus the pump light on the chiral quasi-two-dimensional perovskite film; the chiral quasi-two-dimensional perovskite film is used to generate stimulated radiation under the action of the pump light and the optical resonant cavity to generate circularly polarized laser light.

[0033] According to an embodiment of the present disclosure, the pump light generated by the pump laser is vertically incident on the optical resonant cavity and focused on the chiral quasi-two-dimensional perovskite film, so that the chiral quasi-two-dimensional perovskite film generates circularly polarized photons. The circularly polarized photons resonate in the optical resonant cavity and induce stimulated radiation each time they pass through the chiral quasi-two-dimensional perovskite film, thereby obtaining circularly polarized laser light. Since the circularly polarized photons generated by the chiral quasi-two-dimensional perovskite film resonate in the optical resonant cavity, the light intensity and polarization degree of the circularly polarized laser light are increased. In addition, the polarization degree of the circularly polarized laser light is controlled by the chirality of the chiral quasi-two-dimensional perovskite film to obtain a circularly polarized laser light with a higher polarization degree.

[0034] According to an embodiment of the present disclosure, the optical resonant cavity further includes two distributed Bragg reflectors arranged relatively parallel to each other; the chiral quasi-two-dimensional perovskite film is arranged between the two distributed Bragg reflectors.

[0035] According to an embodiment of the present disclosure, the optical resonant cavity may be a vertical cavity surface emitting laser cavity, and the active region of the vertical cavity surface emitting laser cavity is a chiral quasi-two-dimensional perovskite film.

[0036] According to an embodiment of the present disclosure, a chiral quasi-two-dimensional perovskite film is coated on one of the opposite surfaces of two distributed Bragg reflectors.

[0037] According to an embodiment of the present disclosure, a chiral quasi-two-dimensional perovskite film is coated on one of two distributed Bragg reflectors, and then the other distributed Bragg reflector, which is not coated with the chiral quasi-two-dimensional perovskite film, is closely attached to the other side of the chiral quasi-two-dimensional perovskite film. The chiral perovskite layer can be applied to one of the distributed Bragg reflectors by spin coating using a spin coater to form a thin film.

[0038] According to an embodiment of the present disclosure, the chiral ligand of the chiral quasi-two-dimensional perovskite is , perovskite is Chirality refers to the asymmetry of a molecule or crystal, that is, the difference in left-right symmetry. Chiral molecules have two forms, left and right, called enantiomers.

[0039] According to an embodiment of the present disclosure, the pump laser includes a femtosecond laser, a lens, and a first linear polarizer; the femtosecond laser is used to emit a first laser; the lens is used to converge the first laser to obtain a second laser; and the first linear polarizer is used to convert the second laser into linearly polarized light to obtain pump light.

[0040] Figure 1 The schematic diagram shows the structure of a light source for generating circularly polarized laser according to an embodiment of the present disclosure.

[0041] like Figure 1 As shown, a femtosecond laser emits a first laser beam. A lens 1, a first linear polarizer 2, and a vertical cavity surface emitting laser cavity 3 are sequentially arranged in the optical path of the first laser beam. The first laser beam vertically enters the lens 1, the first linear polarizer 2, and the vertical cavity surface emitting laser cavity 3 in sequence, and a circularly polarized laser beam emerges from the vertical cavity surface emitting laser cavity 3. One of the two distributed Bragg reflectors in the vertical cavity surface emitting laser cavity 3 serves as an output mirror. The two distributed Bragg reflectors include a first distributed Bragg reflector and a second distributed Bragg reflector. The optical resonant cavity is used to control the back-and-forth reflection of circularly polarized photons between the two distributed Bragg reflectors in the optical resonant cavity. Each time the photons pass through the chiral quasi-two-dimensional perovskite film, stimulated emission of light, generates circularly polarized laser light, and emits the circularly polarized laser light from the output mirror. The circularly polarized photons are generated by the radiation of spin-polarized carriers generated by the chiral quasi-two-dimensional perovskite film under the action of pump light. For example, the first distributed Bragg reflector is the first distributed Bragg reflector that the pump light passes through when entering the vertical cavity surface emitting laser cavity, and the second distributed Bragg reflector serves as the output mirror for the output circularly polarized laser light.

[0042] According to an embodiment of the present disclosure, the wavelength of the pump light incident on the vertical cavity surface emitting laser cavity is in the range of 380 nm to 490 nm, and the energy density of the pump light is greater than or equal to 130 μJ / cm².

[0043] Figure 2 The figure schematically shows the structure of a detection device for a light source generating circularly polarized laser light according to another embodiment of the present disclosure.

[0044] like Figure 2 As shown, a detection device for a light source that generates circularly polarized laser light comprises: a quarter wave plate 4, a second linear polarizer 5, a lens combination and an optical fiber collector 8; the light source that generates circularly polarized laser light is used to emit the circularly polarized laser light to be detected, and control the circularly polarized laser light to be detected to be vertically incident on the quarter wave plate 4; the circularly polarized laser light to be detected includes left-handed circularly polarized light and right-handed circularly polarized light; the quarter wave plate 4 is used to convert the left-handed circularly polarized light into a first linear polarized light, and convert the right-handed circularly polarized light into a second linear polarized light, and control the first linear polarized light and the second linear polarized light to be vertically incident on the second linear polarizer 5; the second linear polarizer 5 is used to emit the linear polarization of the first linear polarizer and the second linear polarizer that is parallel to the transmission direction of the second linear polarizer to obtain a third linear polarized light; the lens combination is used to focus the third linear polarized light onto the receiving end of the optical fiber collector.

[0045] According to an embodiment of the present disclosure, the lens combination includes a first convex lens 6 and a second convex lens 7; the first convex lens 6 is used to convert the polarized light emitted from the second linear polarizer 5 into parallel light; the second convex lens 7 is used to focus the parallel light to the receiving end of the optical fiber collector 8.

[0046] Figure 3 A flowchart schematically illustrates a method for designing a light source for generating circularly polarized laser light according to an embodiment of the present disclosure.

[0047] like Figure 3 As shown, the method includes operations S301 to S305.

[0048] In operation S301 , a chiral quasi-two-dimensional perovskite thin film is prepared.

[0049] In operation S302 , circular polarization optical properties of the chiral quasi-two-dimensional perovskite thin film are detected using circular dichroism spectroscopy and circularly polarized luminescence spectroscopy.

[0050] In operation S303 , a vertical cavity surface emitting laser cavity is formed using two distributed Bragg reflectors (DBRs), and a chiral perovskite layer is coated on one of the DBR mirrors by spin coating to form a thin film.

[0051] In operation S304 , a femtosecond laser, a lens, and a first linear polarizer are used to generate a beam of linearly polarized light, which is focused onto the thin film sample as pump light.

[0052] In operation S305 , a detection device is placed behind the vertical cavity surface emitting laser cavity to detect the circular polarization degree of the circularly polarized laser light.

[0053] According to an embodiment of the present disclosure, the film formed on a DBR mirror is a chiral quasi-two-dimensional perovskite film. First, a chiral quasi-two-dimensional perovskite film is prepared, and then the circular dichroism spectrum and circularly polarized luminescence spectrum are used to detect the circularly polarized optical properties of the chiral quasi-two-dimensional perovskite film, that is, the circular dichroism spectrum and circularly polarized luminescence spectrum of the prepared chiral quasi-two-dimensional perovskite film are measured. Specifically, the circular dichroism spectrum of the film in the wavelength range of 330nm~380nm is measured, and the circularly polarized luminescence spectrum of the film in the wavelength range of 500nm~580nm is measured. The anisotropy factor is measured according to the following formula:

[0054] (1)

[0055] Where, Anisotropy factor representing the absorption and emission of light; Represents the intensity of absorbed and emitted left-handed circularly polarized light; Represents the intensity of absorbed and emitted right-handed circularly polarized light.

[0056] The calculated anisotropy factor can be used to predict the anisotropy factor of the circularly polarized laser generated by the prepared film under the action of pump light and vertical cavity surface emitting laser cavity.

[0057] By precalculating and estimating the anisotropy factor of the circularly polarized laser light generated by the prepared film, film samples that meet a first preset requirement can be selected from multiple prepared films, while film samples that fail to meet a second preset requirement can be pre-selected. The first preset requirement is that the anisotropy factor of the prepared film must be greater than a preset first anisotropy factor, and the second preset requirement is that the anisotropy factor of the circularly polarized laser light generated by the film must be greater than a preset second anisotropy factor.

[0058] Through operations S301 and S302, a suitable thin film sample is selected for subsequent steps. Based on the selected thin film sample, a corresponding chiral perovskite layer is determined and coated onto a DBR mirror to form a chiral quasi-two-dimensional perovskite film. Two DBR mirrors form a vertical cavity surface emitting laser cavity, with the chiral quasi-two-dimensional perovskite film formed on one of the DBR mirrors. The chiral quasi-two-dimensional perovskite film is then irradiated with pump light that meets the requirements, causing the vertical cavity surface emitting laser cavity to generate stimulated radiation, producing circularly polarized laser light. This circularly polarized laser light corresponds to the chiral quasi-two-dimensional perovskite film. For example, the wavelength of the pump light can be selected to be 480 nm, resulting in a circularly polarized light wavelength of 527 nm.

[0059] The circular polarization degree of the circularly polarized laser is detected by a detection device. The circular polarization degree of the circularly polarized laser is calculated according to formula (2):

[0060] (2)

[0061] Where, Anisotropy factor representing the absorption and emission of light; Represents the intensity of left-handed circularly polarized laser light; Represents the intensity of right-handed circularly polarized laser light.

[0062] Figure 4 The device structure diagram schematically shows the design process of a light source for generating circularly polarized laser light according to an embodiment of the present disclosure.

[0063] like Figure 4 As shown in the figure, the first laser generated by the femtosecond laser passes through lens 1 to obtain a converged second laser, which then passes through the first linear polarizer 2 to obtain pump light. The lens can be a convex lens. The vertical cavity surface emitting laser cavity 3 is formed by two DBR mirrors to form a laser cavity, with the gain medium located in the middle. A right-handed chiral perovskite layer is coated on one of the DBR mirrors by spin coating to form a chiral quasi-two-dimensional perovskite film. The pump light is converged on the chiral quasi-two-dimensional perovskite film and generates stimulated radiation in the vertical cavity surface emitting laser cavity, thereby obtaining circularly polarized laser light. The detection device is used to detect the circular polarization degree of the circularly polarized laser light emitted by the vertical cavity surface emitting laser cavity. A linear polarizer and a quarter-wave plate 4 are used to detect the circular polarization of the generated laser light. The angle of the quarter-wave plate 4 is adjusted to control the amount of light with different polarizations passing through the second linear polarizer 5. The laser intensity changes periodically with the wave plate angle, so that the circular polarization degree of the circularly polarized laser light can be calculated using formula (2). The different polarizations refer to left-handed circularly polarized light and right-handed circularly polarized light. The lens assembly is used to focus the third linearly polarized light onto the receiving end of the optical fiber collector. The lens assembly includes a first convex lens 6 and a second convex lens 7. The first convex lens 6 is used to convert the polarized light emitted from the second linear polarizer 5 into parallel light. The second convex lens 7 is used to focus the parallel light onto the receiving end of the optical fiber collector 8.

[0064] According to the embodiments of the present disclosure, by changing the chirality of the optical gain medium and detecting the circular polarization of the vertical cavity surface emitting laser after excitation, the effect of controlling the circular polarization of the laser through the chirality of the quasi-two-dimensional perovskite is achieved.

[0065] Figure 5 A schematic diagram shows the principle of vertical cavity surface emitting laser cavity amplifying the circular polarization of light emitted by chiral materials. Figure 6 The figure schematically shows the test results of the circular polarization of the laser emitted by the vertical cavity surface emitting circularly polarized laser. Figure 7 The diagram schematically shows the threshold test diagram of laser generation by a vertical cavity surface emitting circularly polarized laser.

[0066] application Figure 5 The principle of vertical cavity surface emitting laser cavity amplifying the circular polarization of light emitted by chiral materials is explained in detail.

[0067] like Figure 5 As shown in the figure, in the perovskite structure, the octahedral structure can only accommodate smaller ions, while chiral molecules are located on the surface as ligands. Chiral ligands can induce asymmetric distortion of the perovskite lattice, or interact electronically with the perovskite, thereby giving the perovskite structure material chirality. This leads to the energy splitting of exciton states with opposite spins, which in turn causes the absorption peaks of different circularly polarized light to shift, which appears as a differential signal in the circular dichroism absorption spectrum. Under the Boltzmann distribution, carriers tend to occupy lower energy states. Due to the energy level splitting, the two spin exciton states will produce unbalanced carrier occupation, thereby achieving circularly polarized emission with low polarization degree and small optical gain difference. Under the excitation of pump light with an energy density greater than or equal to the threshold, the weak circularly polarized light is amplified into a strong circularly polarized laser in the vertical cavity surface emitting laser cavity. As shown in the figure, Figure 5 As shown in Figure 1, the two photons with different circular polarizations have different amplification intensities in the laser cavity, resulting in an enhanced circular polarization of the final laser. The two photons with different circular polarizations refer to left-handed circularly polarized photons and right-handed circularly polarized photons.

[0068] application Figure 6 It is demonstrated that the circular polarization of the laser emitted by the vertical cavity surface emitting circularly polarized laser is enhanced.

[0069] like Figure 6 As shown in the figure, under the irradiation of pump light with an energy density greater than or equal to the threshold, the angle of the quarter-wave plate is adjusted to control the amount of light with different polarizations passing through the second linear polarizer; the intensity of the circularly polarized laser shows a periodic change with the change of the angle of the quarter-wave plate, as shown in the figure. Figure 6 As shown in the figure, the strongest intensity appears at an angle of 135 degrees and the weakest intensity appears at an angle of 45 degrees, confirming that the emitted light is indeed right-handed circularly polarized light, which is consistent with the chirality of the chiral ligand. Figure 6 As shown in the figure, the intensity of the spontaneously emitted light does not change significantly with the wave plate angle. Therefore, the circular polarization degree of the circularly polarized laser is significantly enhanced after amplification in the VCSEL cavity.

[0070] like Figure 7 To accurately determine the pump light threshold for generating circularly polarized laser light, the peak value of the circularly polarized light is fitted as a function of the pump light energy density. The power dependence below and above the energy density threshold is fitted to two linear segments, and the intersection point is set as the pump light energy density threshold. Figure 7 The fitting results are shown, and the threshold value of the pump light energy density is 130μJ / cm².

[0071] According to the embodiments of the present disclosure, by changing the chirality of the optical gain medium and detecting the circular polarization of the circularly polarized laser emitted by the vertical cavity surface emitting laser cavity after excitation, the effect of controlling the circular polarization of the laser through the chirality of the quasi-two-dimensional perovskite is achieved.

[0072] The above describes the embodiments of the present disclosure. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A light source for generating circularly polarized laser light, characterized in that: The light source includes: a pump laser and an optical resonant cavity with a chiral quasi-two-dimensional perovskite film as an optical gain medium; The pump laser is used to generate pump light, control the pump light to be vertically incident on the optical resonant cavity, and focus the pump light on the chiral quasi-two-dimensional perovskite film; The chiral quasi-two-dimensional perovskite film is used to generate stimulated radiation under the action of the pump light and the optical resonant cavity to generate circularly polarized laser light.

2. The light source for generating circularly polarized laser light according to claim 1, wherein: The optical resonant cavity further includes two distributed Bragg reflectors arranged in parallel with each other; the chiral quasi-two-dimensional perovskite film is arranged between the two distributed Bragg reflectors.

3. The light source for generating circularly polarized laser light according to claim 1, wherein: The pump laser includes a femtosecond laser, a lens and a first linear polarizer; The femtosecond laser is used to emit a first laser; The lens is used to converge the first laser to obtain a second laser; The first linear polarizer is used to convert the second laser into linearly polarized light to obtain the pump light.

4. The light source for generating circularly polarized laser light according to claim 2, wherein: The chiral quasi-two-dimensional perovskite film is coated on one of the opposite surfaces of the two distributed Bragg reflectors.

5. The light source for generating circularly polarized laser light according to claim 4, characterized in that: The chiral ligand of the chiral quasi-two-dimensional perovskite is , perovskite is .

6. The light source for generating circularly polarized laser light according to claim 1, wherein: The wavelength of the pump light ranges from 380 nm to 490 nm.

7. The light source for generating circularly polarized laser light according to claim 1, characterized in that: The energy density of the pump light is greater than or equal to 130 μJ / cm².

8. The light source for generating circularly polarized laser light according to claim 2, wherein: One of the two distributed Bragg reflectors is an output mirror; the two distributed Bragg reflectors include a first distributed Bragg reflector and a second distributed Bragg reflector; The optical resonant cavity is used to control circularly polarized photons to reflect back and forth between the two distributed Bragg reflectors of the optical resonant cavity, and induce stimulated emission each time they pass through the chiral quasi-two-dimensional perovskite film, generating circularly polarized laser light, and emitting the circularly polarized laser light from the output mirror; wherein, the circularly polarized photons are obtained by radiating spin-polarized carriers generated by the chiral quasi-two-dimensional perovskite film under the action of the pump light.

9. A detection device for a light source generating circularly polarized laser light according to any one of claims 1 to 8, characterized in that: The detection device includes: a quarter wave plate, a second linear polarizer, a lens assembly and an optical fiber collector; The light source for generating circularly polarized laser light is used to emit circularly polarized laser light to be detected, and control the circularly polarized laser light to be detected to be vertically incident on the quarter wave plate; the circularly polarized laser light to be detected includes left-handed circularly polarized light and right-handed circularly polarized light; The quarter wave plate is used to convert the left-handed circularly polarized light into a first linearly polarized light, convert the right-handed circularly polarized light into a second linearly polarized light, and control the first linearly polarized light and the second linearly polarized light to be perpendicularly incident on the second linear polarizer; The second linear polarizer is used to emit the linear polarization of the first linear polarized light and the second linear polarized light that is parallel to the transmission direction of the second linear polarizer to obtain a third linear polarized light; The lens assembly is used to focus the third linearly polarized light onto the receiving end of the optical fiber collector.

10. The detection device for a light source generating circularly polarized laser light according to claim 9, characterized in that: The lens combination includes a first convex lens and a second convex lens; The first convex lens is used to convert the polarized light emitted from the second linear polarizer into parallel light; The second convex lens is used to focus the parallel light onto the receiving end of the optical fiber collector.

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