A quantum fluorescence excitation regulation device suitable for ultrahigh vacuum and low temperature environment

Abstract

The application discloses a quantum fluorescence excitation regulation device suitable for ultrahigh vacuum and low-temperature environment, which comprises a substrate, a waveguide medium layer and a low-dimensional material color center layer arranged on the substrate in sequence; a first optical waveguide structure, a second optical waveguide structure, a fiber-waveguide coupling structure and an electro-optic modulator are arranged in the waveguide medium layer, the fiber-waveguide coupling structure is located at a first end of the first optical waveguide structure and connected with an input optical fiber, a second end of the first optical waveguide structure is connected with a first end of the second optical waveguide structure, and the electro-optic modulator is located on the second optical waveguide structure and adjacent to the first end of the second optical waveguide structure. According to the scheme, the excitation light source for laser and regulation of the color center is transmitted to the back of the low-dimensional material color center layer in the form of an optical waveguide, and the excited quantum fluorescence can be detected and collected on the front of the low-dimensional material color center layer, so that the color center regulation precision and the optical signal reading efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of quantum optics technology, specifically to a quantum fluorescence excitation and control device suitable for ultra-high vacuum and low temperature environments. Background Technology

[0002] In the fields of quantum light sources and optical sensors, the study of color centers in low-dimensional materials has attracted widespread attention. Low-dimensional material color centers are defect structures located at the atomic or nanoscale, capable of emitting, detecting, and manipulating single photons or spin defects. Low-dimensional material color centers possess several unique advantages, including high spontaneous emission intensity, good optical stability, and long quantum state lifetimes. These characteristics make them potential candidates for realizing efficient, precise, and controllable single-photon sources and optical sensors. This design concept is based on a deep understanding of the microstructure and energy levels of color centers, endowing them with many excellent properties.

[0003] Two-dimensional color center materials, represented by hexagonal boron nitride (h-BN) color centers, are gradually emerging as a new potential quantum bit platform following diamond color centers. Compared to diamond color centers, h-BN color centers possess higher optical quantum efficiency, narrower emission linewidth, longer electron spin lifetime, and longer spin coherence time. In particular, for two-dimensional material systems, using color centers as single-photon emitters or applying means of controlling the spin electrons within them (such as pump lasers) eliminates the need for light to pass through a thick crystal, allowing direct interaction with the color center. Since the light does not undergo significant scattering and absorption, attenuation and distortion of the controlled or received optical signal are avoided, reducing the difficulty of optical access and improving the efficiency of optical readout.

[0004] Currently, methods for color center manipulation include photoexcitation of color centers using pump lasers or microwave pulses, combined with temperature, magnetic, and electric field control, nuclear magnetic resonance (NMR) technology, and electron spin resonance (ESR) technology, to alter the energy level layout of the color centers, manipulate their spin states, and achieve coherent transitions between quantum states. Existing technologies typically employ confocal microscopy systems, where the excitation light source is emitted from the microscope lens to the color center, and the fluorescence signal excited by the color center is also detected and collected by the microscope lens. However, due to the inherent structural design of the equipment (confocal microscopy system) (such as filters and semi-transparent mirrors), significant loss of the excited fluorescence signal occurs. Summary of the Invention

[0005] In view of this, the present invention provides a quantum fluorescence excitation and control device that can improve the accuracy of color center control and the efficiency of optical signal reading, and is suitable for ultra-high vacuum and low temperature environments.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A quantum fluorescence excitation and modulation device suitable for ultra-high vacuum and low temperature environments includes a substrate and a waveguide dielectric layer and a low-dimensional material color center layer sequentially disposed on the substrate. The waveguide dielectric layer contains a first optical waveguide structure, a second optical waveguide structure, an optical fiber-waveguide coupling structure, and an electro-optic modulator. The optical fiber-waveguide coupling structure is located at a first end of the first optical waveguide structure and connected to an input optical fiber. The second end of the first optical waveguide structure is connected to the first end of the second optical waveguide structure. The electro-optic modulator is located on the second optical waveguide structure and adjacent to the first end of the second optical waveguide structure.

[0008] The external excitation light source is transmitted through the input optical fiber and the first optical waveguide structure into the second optical waveguide structure. After being modulated by the electro-optic modulator, it is transmitted along the second optical waveguide structure and coupled out to the low-dimensional material color center layer for quantum fluorescence excitation.

[0009] Preferably, the waveguide dielectric layer is provided with a plurality of second optical waveguide structures arranged in parallel, and a polarization beam splitter is also provided; the polarization beam splitter is located at the second end of the first optical waveguide structure, the first end of each second optical waveguide structure is connected to the second end of the first optical waveguide structure through the polarization beam splitter, and each second optical waveguide structure is provided with an electro-optic modulator.

[0010] Preferably, the waveguide dielectric layer contains 3 to 6 second optical waveguide structures arranged in parallel.

[0011] Preferably, the substrate is a silicon-based substrate.

[0012] Preferably, the waveguide dielectric layer is made of silicon dioxide, silicon, germanium, lithium niobate, sapphire, or transparent ceramic material.

[0013] Preferably, the thickness of the waveguide dielectric layer is 20 nm to 1.5 μm.

[0014] Preferably, the material of the low-dimensional material color center layer is a two-dimensional color center material, which is selected from any one of two-dimensional h-BN color center material, two-dimensional MoS2 color center material, two-dimensional GaN color center material, two-dimensional ZnO color center material and two-dimensional WO3 color center material.

[0015] Preferably, the quantum fluorescence excitation control device further includes a microwave generator for generating microwave pulses and transmitting the microwave pulses to the low-dimensional material color center layer.

[0016] The quantum fluorescence excitation and control device for ultra-high vacuum and low temperature environments provided in this invention applies a laser-controlled excitation source to the back side of a low-dimensional material color center layer via an optical waveguide. The excited quantum fluorescence can be detected and collected on the front side of the low-dimensional material color center layer, which can improve the accuracy of color center control and the efficiency of optical signal reading.

[0017] Furthermore, the quantum fluorescence excitation and control device provided in this embodiment of the invention integrates the low-dimensional material color center layer used to generate quantum fluorescence and the waveguide dielectric layer used to conduct the input excitation light source on the same substrate. The entire device is solid-state and miniaturized, eliminating the dependence on macroscopic discrete optical components in existing quantum fluorescence excitation and control devices, and is particularly suitable for extreme operating environments such as ultra-high vacuum and low temperature. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the quantum fluorescence excitation and control device in an embodiment of the present invention;

[0019] Figure 2 This is an exemplary cross-sectional view of the quantum fluorescence excitation control device in an embodiment of the present invention;

[0020] Figure 3 This is an exemplary illustration of the quantum fluorescence excitation and control process in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in and described with reference to the drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0022] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0023] This invention provides a quantum fluorescence excitation control device suitable for ultra-high vacuum and low temperature environments. (See attached document.) Figures 1 to 3 The quantum fluorescence excitation control device includes a substrate 10 and a waveguide dielectric layer 20 and a low-dimensional material color center layer 30 sequentially disposed on the substrate 10. It should be noted that, in order to illustrate the structural layer located below the low-dimensional material color center layer 30, Figure 1 The image shows only a portion of the low-dimensional material color center layer 30.

[0024] The waveguide dielectric layer 20 includes a first optical waveguide structure 21, a second optical waveguide structure 22, an optical fiber-waveguide coupling structure 23, and an electro-optic modulator 24. The optical fiber-waveguide coupling structure 23 is located at the first end of the first optical waveguide structure 21 and connected to the input optical fiber 40. The second end of the first optical waveguide structure 21 is connected to the first end of the second optical waveguide structure 22. The electro-optic modulator 24 is located on the second optical waveguide structure 22 and is adjacent to the first end of the second optical waveguide structure 22.

[0025] As described above, in the quantum fluorescence excitation control device, an external excitation light source is transmitted through the input optical fiber 40 and the first optical waveguide structure 21 into the second optical waveguide structure 22. After being modulated by the electro-optic modulator 24, it is transmitted along the second optical waveguide structure 22 and coupled out to the low-dimensional material color center layer 30 to excite the color centers 31 in the low-dimensional material color center layer 30 with quantum fluorescence.

[0026] As a preferred embodiment, see [reference]. Figure 1 The waveguide dielectric layer 20 contains a plurality of parallel-arranged second optical waveguide structures 22 and a polarization beamsplitter 25. The polarization beamsplitter 25 is located at the second end of the first optical waveguide structure 21. The first end of each second optical waveguide structure 22 is connected to the second end of the first optical waveguide structure 21 via the polarization beamsplitter 25. Each second optical waveguide structure 22 is equipped with an electro-optic modulator 24. An external excitation light source is transmitted through the input optical fiber 40 and the first optical waveguide structure 21, and is split by the polarization beamsplitter 25 and transmitted into each of the second optical waveguide structures 22. After modulation by the corresponding electro-optic modulator 24 on each second optical waveguide structure 22, the light is transmitted along the corresponding second optical waveguide structure 22 and coupled out to the low-dimensional material color center layer 30 to excite the color center 31 using quantum fluorescence.

[0027] Each of the electro-optic modulators 24 can be controlled independently. Therefore, different states of excitation light sources can be applied to the color centers in different regions of the low-dimensional material color center layer 30 to excite and regulate them according to actual needs.

[0028] As a preferred embodiment, in this embodiment, four second optical waveguide structures 22 are arranged in parallel in the waveguide dielectric layer 20. In other embodiments, the number of second optical waveguide structures 22 is preferably set to 3 to 6.

[0029] As a preferred embodiment of the present invention, the substrate 10 is preferably a silicon-based substrate, such as silicon, silicon carbide, or silicon insulated substrate (SOI) and its thickness is preferably a thickness that meets the minimum mechanical stability requirements of the on-chip system.

[0030] As a preferred embodiment of the invention, the waveguide dielectric layer 20 is made of silicon dioxide (SiO2). In other embodiments, the waveguide dielectric layer 20 may also be made of silicon, germanium, lithium niobate, sapphire, or transparent ceramic. The growth process of SiO2 material is compatible with existing semiconductor process technologies and can be directly grown on the substrate 10. The first optical waveguide structure 21, the second optical waveguide structure 22, the fiber-waveguide coupling structure 23, the electro-optic modulator 24, and the polarization beamsplitter 25 can be directly formed in the waveguide dielectric layer 20. The first optical waveguide structure 21, the second optical waveguide structure 22, the fiber-waveguide coupling structure 23, the electro-optic modulator 24, and the polarization beamsplitter 25 are all fabricated using existing mature process methods. The thickness of the waveguide dielectric layer 30 is preferably 20 nm to 1.5 μm.

[0031] For example, a wet oxidation process can be used to form a waveguide dielectric layer 20 of SiO2 material on the surface of substrate 10. Then, a focused femtosecond laser pulse is used to scan the SiO2 material. A nonlinear multiphoton absorption process will occur in the irradiated area, inducing a change in the refractive index of a local area in the SiO2 material. As a result, structures such as a first optical waveguide structure 21, a second optical waveguide structure 22, an optical fiber-waveguide coupling structure 23, an electro-optic modulator 24, and a polarization beam splitter 25 are formed in the waveguide dielectric layer 20.

[0032] The low-dimensional material color center layer 30 located on the waveguide dielectric layer 20 includes a plurality of color centers 31, which are excited by an excitation light source to generate quantum fluorescence. As a preferred embodiment of the invention, the material of the low-dimensional material color center layer is a two-dimensional h-BN color center material. In other embodiments, the material of the low-dimensional material color center layer can also be a two-dimensional color center material such as two-dimensional MoS2, two-dimensional GaN, two-dimensional ZnO, or two-dimensional WO3.

[0033] Specifically, in this embodiment of the invention, a transfer method can be used to transfer two-dimensional h-BN color center materials grown on other substrates to the surface of the waveguide dielectric layer 20. It should be noted that directly growing two-dimensional h-BN color center materials on the surface of the waveguide dielectric layer 20 using chemical vapor deposition (CVD) is quite difficult. A possible approach is to first pre-deposit a layer of metal catalyst (such as nickel or platinum) on the surface of the waveguide dielectric layer 20, and then use CVD to grow the two-dimensional h-BN color center material layer.

[0034] As a preferred embodiment of the present invention, such as Figure 3As shown, the quantum fluorescence excitation control device also includes a microwave generator (not shown in the figure), which is used to generate microwave pulses and transmit the microwave pulses to the low-dimensional material color center layer 30.

[0035] See Figure 3 The working mechanism of the quantum fluorescence excitation control device provided in this embodiment of the invention includes:

[0036] (1) A pump laser with a specific wavelength (e.g., 532nm) is coupled to the back side of the low-dimensional material color center layer 30 through the waveguide dielectric layer 20 to excite the color center 31. The excited color center is located and detected by the confocal microscopy system 50 set on the front side of the low-dimensional material color center layer 30, and the quantum fluorescence generated by the excitation is collected.

[0037] Optical excitation and fluorescence modulation of transitions between defect energy levels, coupled with the flexible tunability of lasers, allow for precise control of h-BN color centers. A specific pump laser is transmitted via optical fiber and directionally coupled to the input of an optical waveguide cavity. The optical signal then connects to an integrated polarization beamsplitter and electro-optic modulator via the waveguide path, controlling the polarization, intensity, or phase of the light. The optical signal then moves along the waveguide path, coupling to the excited color center via the waveguide, thereby achieving modulation and manipulation of the color center. Typically, the selected pump laser wavelength should match the absorption peak of the target color center to provide sufficient energy to induce a transition to the excited state. For different color center types, it may be necessary to select an appropriate pump laser wavelength for its specific energy level structure, thereby exciting color centers with specific electronic level layouts.

[0038] Light intensity modulation: By adjusting the intensity of the laser light source, the optical response of the color center can be controlled. Specifically, increasing or decreasing the intensity of the additional light source can correspondingly change the excitation rate and fluorescence intensity of the color center. This method is commonly used in photonic computing and quantum information processing.

[0039] Optical pulse modulation: By using a sequence of optical pulses generated by a laser source, the behavior of color centers can be modulated at different time scales. Specifically, by changing parameters such as the repetition frequency, width, and interval of the laser pulses, the spin states of color centers can be manipulated. For example, optical pulse sequences can be used to initialize, read out, and manipulate color centers.

[0040] Optical frequency tuning: Adjusting the frequency of the laser source to match the resonant frequency of the color center allows for more precise manipulation of the color center. Specifically, by adjusting the frequency of the source, specific energy level transitions of the color center can be selectively driven, thereby enabling manipulation of the color center's spin state.

[0041] Optical polarization control: By changing the polarization state of the laser source, the optical response and spin state of the color center can be controlled. Specifically, by selecting an appropriate polarization state based on the energy level structure and optical polarization characteristics of the color center, the color center can be manipulated and read out.

[0042] (2) By irradiating the surface of the low-dimensional material color center layer 30 with microwave pulses generated by a microwave generator, the distribution of electrons among several spin-orbit coupled sub-levels such as |s=0>, |s=1>, and |s=-1> can be adjusted. Microwave radiation can manipulate the spin state of electrons through resonance effects. When the frequency of the microwave pulse matches the energy difference between the electron energy levels, resonant absorption or emission will occur. By adjusting the frequency of the microwave, electrons can be prompted to transition from one spin state to another, thereby changing their distribution.

[0043] Furthermore, the quantum fluorescence excitation and control device provided in the above embodiment integrates the low-dimensional material color center layer used to generate quantum fluorescence and the waveguide dielectric layer used to conduct the input excitation light source on the same substrate. The entire device is solid-state and miniaturized, eliminating the dependence on macroscopic discrete optical components such as monochromators and electro-optic modulators in existing quantum fluorescence excitation and control devices. It is particularly suitable for extreme operating environments such as ultra-high vacuum and low temperature.

[0044] It should be noted that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A quantum fluorescence excitation and control device suitable for ultra-high vacuum and low temperature environments, characterized in that, The device includes a substrate and a waveguide dielectric layer and a low-dimensional material color center layer sequentially disposed on the substrate. The waveguide dielectric layer contains a first optical waveguide structure, a second optical waveguide structure, an optical fiber-waveguide coupling structure, and an electro-optic modulator. The optical fiber-waveguide coupling structure is located at a first end of the first optical waveguide structure and connected to an input optical fiber. The second end of the first optical waveguide structure is connected to the first end of the second optical waveguide structure. The electro-optic modulator is located on the second optical waveguide structure and adjacent to its first end. An external excitation source is transmitted through the input optical fiber and the first optical waveguide structure into the second optical waveguide structure, modulated by the electro-optic modulator, and then transmitted along the second optical waveguide structure and coupled out to the low-dimensional material color center layer for quantum fluorescence excitation. The waveguide dielectric layer is provided with a plurality of second optical waveguide structures arranged in parallel, and a polarization beam splitter is also provided; the polarization beam splitter is located at the second end of the first optical waveguide structure, the first end of each second optical waveguide structure is connected to the second end of the first optical waveguide structure through the polarization beam splitter, and each second optical waveguide structure is provided with an electro-optic modulator.

2. The quantum fluorescence excitation and control device according to claim 1, characterized in that, The waveguide dielectric layer contains 3 to 6 second optical waveguide structures arranged in parallel.

3. The quantum fluorescence excitation and control device according to claim 1, characterized in that, The substrate is a silicon-based substrate.

4. The quantum fluorescence excitation and control device according to claim 1, characterized in that, The waveguide dielectric layer is made of silicon dioxide, silicon, germanium, lithium niobate, sapphire, or transparent ceramic materials.

5. The quantum fluorescence excitation and control device according to claim 4, characterized in that, The thickness of the waveguide dielectric layer is 20 nm to 1.5 μm.

6. The quantum fluorescence excitation and control device according to claim 1, characterized in that, The material of the low-dimensional material color center layer is a two-dimensional color center material, which is selected from any one of two-dimensional h-BN color center material, two-dimensional MoS2 color center material, two-dimensional GaN color center material, two-dimensional ZnO color center material and two-dimensional WO3 color center material.

7. The quantum fluorescence excitation control device according to any one of claims 1-6, characterized in that, The quantum fluorescence excitation control device also includes a microwave generator for generating microwave pulses and transmitting the microwave pulses to the color center layer of the low-dimensional material.

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