A high-Q gigahertz resonator and resonant method

Abstract

The application discloses a high-Q gigahertz resonator, and belongs to the field of high-frequency MEMS devices, comprising: a supporting substrate, wherein a through hole is arranged in the middle; a surrounding substrate arranged on the supporting substrate, wherein an opening is arranged in the plane; the cross-sectional area of the opening is smaller than that of the through hole; and a nano-beam, both ends of which are fixed inside the opening; the nano-beam is composed of a plurality of cross-shaped unit cells arranged periodically, the cross-shaped unit cells at both ends form mirrors, and the remaining cross-shaped unit cells form a resonant cavity, and the nano-beam is symmetric about the center of the cavity; the cross-shaped unit cell is an acousto-optic photonic crystal; the width of the cross-shaped unit cell is greater than the lattice constant; the geometric parameters of the cross-shaped unit cells in the mirrors are the same, and the geometric parameters of the cross-shaped unit cells in the resonant cavity gradually change from both ends to the center of the resonant cavity, specifically: p(x) = 2x 3 -3x 2 +1. The resonator provided by the application can simultaneously meet the requirements of gigahertz high-frequency mechanical vibration and high Q value.

Description

Technical Field

[0001] This invention belongs to the field of high-frequency MEMS devices, and more specifically, relates to a high-Q gigahertz resonator and a resonance method. Background Technology

[0002] Microelectromechanical systems (MEMS) have captured a significant share of the industrial market due to their miniaturization and high frequency capabilities. With the rapid development of various radio frequency (RF) systems, such as 5G mobile communications and satellite wireless communications, the market demand for high-frequency resonators and filters has increased dramatically, making high-quality high-frequency resonators a key research focus. Their high frequency, low loss (i.e., high Q value), and small mass make them core components for next-generation clocks, filters, resonant sensors, and quantum technologies.

[0003] Based on the inverse piezoelectric effect, quartz resonators, surface acoustic wave (SAW) devices, and interdigital transducers (IDTs) can be used for resonators ranging from kHz to MHz. Furthermore, some specialized SAWs can also operate in the GHz range, but are primarily used in the low-frequency market due to limitations in phase velocity and lithography. To meet the needs of today's wireless communication technologies, thin-film cavity acoustic resonator (FBAR) filters can generate GHz resonances and exhibit excellent performance in terms of temperature stability. Moreover, existing technologies typically require piezoelectric materials with external RF excitation, which is difficult to integrate into existing complementary metal-oxide-semiconductor (CMOS) devices.

[0004] In recent years, photomechanical systems have made significant progress in areas such as the quantum ground state of laser-cooled nanomechanical oscillators, phonon lasers, thermal transport engineering, and photomechanically induced transparency by utilizing the strong interaction between GHz phonons and photons at communication wavelengths. However, because resonators typically exhibit high Q values ​​and excellent overall resonance performance in ultra-low temperature environments, existing photomechanical system-based resonators are often designed for ultra-low temperature environments, while practical applications are usually conducted at room temperature. Therefore, overcoming the Q-value bottleneck of GHz nanoresonators at room temperature remains a pressing issue. Summary of the Invention

[0005] In view of the shortcomings of the existing technology and the need for improvement, the present invention provides a high Q value gigahertz resonator and resonance method, the purpose of which is to provide a resonator that simultaneously meets the requirements of gigahertz high-frequency mechanical vibration and high Q value.

[0006] To achieve the above objectives, according to one aspect of the present invention, a high-Q gigahertz resonator is provided, comprising:

[0007] A supporting substrate has a through-hole in the middle;

[0008] A surrounding substrate disposed on a support substrate, with an opening formed in its in-plane direction; the cross-sectional area of the opening is smaller than that of the through-hole;

[0009] And a nano-beam, whose two ends are fixed to the inner side of the opening;

[0010] The nano-beam is composed of multiple cross-shaped unit cells arranged periodically. The cross-shaped unit cells at both ends of the nano-beam form the mirrors at both ends, and the remaining cross-shaped unit cells form the resonant cavity. The nano-beam is centrosymmetric about the center of the resonant cavity; the cross-shaped unit cell is a phononic crystal, which has phononic and photonic dual bandgaps.

[0011] Furthermore, the width of the cross-shaped unit cell is greater than the lattice constant.

[0012] Furthermore, the geometric parameters of the cross-shaped unit cells in the mirror are the same; the geometric parameters of the cross-shaped unit cell include: lattice constant, width, thickness, the width of the side in the x direction, and the width of the side in the y direction;

[0013] For the cross-shaped unit cells in the resonant cavity, the lattice constant and the width of the side in the y direction gradually change from both ends of the resonant cavity to the center of the resonant cavity, and the remaining geometric parameters are the same as those of the cross-shaped unit cells in the mirror;

[0014] Among them, the x direction is the arrangement direction of the cross-shaped unit cells, and the y direction is perpendicular to the x direction.

[0015] Furthermore, in the mirror, the lattice constant of the cross-shaped unit cell is a, and the width of the side of the cross-shaped unit cell in the y direction is c; the center of the resonant cavity is the origin in the x direction. For the cross-shaped unit cell located at the center of the resonant cavity, its lattice constant is a1, and its width of the side in the y direction is c1, where a1 < a and c1 < c; the lattice constant a

[0017] , and the width c of the side in the y direction i , respectively are:

[0016]

[0017]

[0018] Among them, i is the serial number of the cross-shaped unit cell in the resonant cavity, and x i is the coordinate of the i-th cross-shaped unit cell in the resonant cavity in the x direction; p(x) is a preset gradient function, and p(x) = 2x 3 - 3x 2 + 1.

[0019] Furthermore, the geometric parameters of the cross-shaped unit cells in the nano-beam satisfy that for the cross-shaped unit cell located at the center of the resonant cavity, the frequency of the third-order acoustic mode T and the frequency of the first-order optical mode O are respectively located in the phonon bandgap and the photon bandgap of the mirrors at both ends of the nano-beam.

[0020] Furthermore, the phonon band gaps of the mirrors at both ends of the nanobeam are complete band gaps.

[0021] Furthermore, the nanobeams and the surrounding substrate are made of the same material and are etched from the same sheet of material.

[0022] Furthermore, the nanobeams and the surrounding substrate are etched from the same SOI silicon wafer.

[0023] Furthermore, the material of the supporting substrate is SiO2. m .

[0024] According to another aspect of the present invention, a resonance method based on the above-described high-Q gigahertz resonator is provided, comprising:

[0025] Using frequency ω L A laser of frequency ω + Ω excites a high-Q gigahertz resonator, causing the laser to blue-shift to a frequency of ω, and simultaneously scattering phonons of frequency Ω in the form of Brillouin scattering, thereby achieving resonance;

[0026] Where Ω is the acoustic cavity mode eigenfrequency of the nanobeam, and ω is the optical cavity mode eigenfrequency of the nanobeam.

[0027] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0028] (1) The high Q value gigahertz resonator provided by the present invention, wherein the nanoscale resonant cavity can realize gigahertz acoustic resonance, and the nanobeam is composed of multiple cross-shaped unit cells arranged periodically. Each cross-shaped unit cell is an acousto-photonic crystal with acousto-photonic dual bandgap. The cross-shaped unit cells at both ends constitute a mirror, and the cross-shaped unit cell in the middle constitutes a resonant cavity. The entire nanobeam is symmetrical about the center of the resonant cavity. This structure supports the resonance of the acoustic cavity mode at GHz and the optical cavity mode near the communication wavelength. Moreover, the displacement field of the acoustic cavity mode and the electric field of the optical cavity mode are highly localized in the resonant cavity, which effectively improves the Q value at room temperature.

[0029] (2) In the preferred embodiment of the high Q-value gigahertz resonator provided by the present invention, the width of the cross-shaped unit cell in the nanobeam is greater than the lattice constant. This allows the displacement of the acoustic third-order mode T in the band structure with ee symmetry of the cross-shaped unit cell to be concentrated in the y direction (perpendicular to the arrangement direction of the cross-shaped unit cell), which has a high degree of overlap with the electric field of the optical first-order mode O. Thus, mode T and mode O form a resonant cavity mode. During acoustic-optical coupling, the superposition of the acoustic and optical fields will not cancel each other out, effectively improving the coupling rate. At the same time, it reduces the sound wave group velocity, making it easier to form an acoustic cavity mode, thereby achieving high Q-value resonance.

[0030] (3) In a preferred embodiment of the high-Q gigahertz resonator provided by the present invention, the width of the cross-shaped unit cell in the resonant cavity and the width of the side in the y-direction gradually decrease from both ends of the resonant cavity to the center of the resonant cavity, thereby enabling a smooth transition between adjacent cross-shaped unit cells in the resonant cavity to reduce electromagnetic scattering loss; more preferably, the lattice constant of the cross-shaped unit cell in the resonant cavity satisfies The width of the edge in the y-direction satisfies It can satisfy the boundary condition dp(x) / dx| x＝0,1 =0, effectively ensuring a smooth transition between adjacent cross-shaped unit cells in the resonant cavity.

[0031] (4) The high Q-value gigahertz resonator provided by the present invention can change the frequency of the acoustic third-order mode T and the optical first-order mode O by changing the geometric parameters of the cross-shaped unit cell in the nanobeam. In the preferred embodiment of the present invention, the geometric parameters of the cross-shaped unit cell in the nanobeam satisfy the following: the frequency of the acoustic third-order mode T and the frequency of the optical first-order mode O of the cross-shaped unit cell located at the center of the resonant cavity are respectively located in the phonon bandgap and photon bandgap of the mirrors at both ends of the nanobeam. This allows the two modes to be reflected by the mirrors and then transitioned from the mirrors to the center of the resonant cavity through several unit cells according to the geometric gradient function. Thus, the acoustic guided mode and the optical guided mode can be generated simultaneously in the bandgap, and the displacement field of the acoustic guided mode and the electric field of the optical guided mode are highly localized in the resonant cavity. More preferably, in this embodiment, the phonon bandgap of the mirror is a complete bandgap, which makes it impossible for the vibration of the resonant cavity to be transmitted to the surrounding substrate from any direction, which greatly improves the Q value.

[0032] (5) In a preferred embodiment of the high Q-value gigahertz resonator provided by the present invention, the nanobeams and the surrounding substrate are etched from the same material, thereby simplifying the fabrication process of the device; more preferably, the nanobeams and the surrounding substrate are etched from the same SOI silicon wafer, thereby enabling the use of existing SOI processes and making the device easy to integrate onto a silicon-based chip. Attached Figure Description

[0033] Figure 1 This is a schematic cross-sectional view of a high-Q gigahertz resonator provided in an embodiment of the present invention;

[0034] Figure 2 The diagram shows the structure of the nanobeam in the high-Q gigahertz resonator provided in the embodiment of the present invention; wherein, (a) is a cross-shaped unit cell structure, (b) is a three-dimensional structural diagram of the nanobeam, (c) is a curve showing the geometric parameters of the cross-shaped unit cell in the nanobeam as a function of coordinates, and (d) is a two-dimensional structural diagram of the nanobeam.

[0035] Figure 3 This is a schematic diagram of the complete phonon bandgap of the reflector;

[0036] Figure 4 A schematic diagram of the laser-excited high-frequency phonon resonator principle provided in an embodiment of the present invention;

[0037] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0038] 1-Nanobeam; 2-Surrounding substrate; 3-Supporting substrate. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0040] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0041] To address the technical problem of low Q-value in gigahertz resonators at room temperature, this invention provides a high-Q gigahertz resonator and resonance method. The basic idea is to design a nano-resonator based on an optical-mechanical system. Specifically, a nanoscale nanobeam is designed to achieve gigahertz acousto-optic resonance. The structure of the nanobeam is designed to support resonance of both GHz acoustic cavity modes and optical cavity modes near communication wavelengths. Furthermore, the displacement field of the acoustic cavity mode and the electric field of the optical cavity mode are highly localized within the resonant cavity, thereby significantly improving the Q-value at room temperature.

[0042] The following is an example.

[0043] Example 1:

[0044] A high-Q gigahertz resonator, its cross-sectional view is shown below. Figure 1 As shown, it includes:

[0045] A support substrate 3 has a through-hole in its center;

[0046] The surrounding substrate 2, which is disposed on the support substrate 3, has an opening in its surface; the cross-sectional area of ​​the opening is smaller than the cross-sectional area of ​​the through hole.

[0047] And nanobeam 1, whose two ends are fixed to the inside of the opening;

[0048] like Figure 2 As shown in (b), the nanobeam 1 is composed of multiple cross-shaped unit cells arranged periodically; the structure of the cross-shaped unit cell is as follows: Figure 2As shown in (a), the cross-shaped unit cell is an acousto-photonic crystal with acousto-photonic dual bandgap; optionally, in this embodiment, the arrangement direction of the cross-shaped unit cells is defined as the x-direction, and the direction perpendicular to the x-direction is defined as the y-direction. Correspondingly, in the cross-shaped unit cell, the two sides are located in the opposite x-direction and the y-direction, respectively; the center of the resonant cavity is defined as the origin of the x-direction, that is, the x-coordinate of the cross-shaped unit cell located at the center of the resonant cavity is x = 0, and the x-coordinate at the interface between the resonant cavity and the mirror is defined as x = 1; as Figure 2 As shown in (d), the nanobeam 1 is symmetrical about the cavity center, the cross-shaped unit cells at both ends constitute the mirrors at both ends, and the remaining cross-shaped unit cells constitute the resonant cavity.

[0049] The high Q-value gigahertz resonator provided in this embodiment, with its nanobeam structure design, enables the nanobeam to simultaneously support the resonance of the acoustic cavity mode at GHz and the optical cavity mode near the communication wavelength. Furthermore, the displacement field of the acoustic cavity mode and the electric field of the optical cavity mode are highly localized in the resonant cavity, effectively improving the Q-value and acousto-optic coupling rate at room temperature.

[0050] Through research, this invention has found that forming the resonant cavity modes using the third acoustic mode and the first optical mode is beneficial for improving the Q value of the resonator. To achieve a strong coupling rate between these two modes, this embodiment further optimizes the structure of the cross-shaped unit cell. Specifically, in this embodiment, the width of the cross-shaped unit cell is greater than the lattice constant; the lattice constant and width of the cross-shaped unit cell are as follows: Figure 2 As shown in (a), w and a, that is, in this embodiment, w>a; through such structural design, the displacement of the acoustic third-order mode T in the band structure with ee symmetry of the cross-shaped unit cell is concentrated in the y direction, and the electric field overlap with the optical first-order mode O is high. Thus, during acousto-optic coupling, the superposition of acousto-optic fields will not cancel each other out, effectively improving the coupling rate; at the same time, the sound wave group velocity is reduced, making it easier to form an acoustic cavity mode, thereby achieving high Q value resonance.

[0051] In a preferred embodiment, in order to make the transition between adjacent cross-shaped unit cells in the resonant cavity smooth and reduce electromagnetic scattering loss, the geometric parameters of the cross-shaped unit cells in the reflector are the same.

[0052] The lattice constant and the width of the side in the y-direction of the cross-shaped unit cell in the resonant cavity gradually decrease from both ends to the center of the resonant cavity, while the other geometric parameters are consistent with those of the cross-shaped unit cell in the mirror.

[0053] Accordingly, this embodiment designs a gradient function for the geometric parameters so that the geometric parameters of the cross-shaped unit cell in the resonant cavity satisfy the boundary condition dp(x) / dx| x＝0,1 =0, achieving a smooth transition between adjacent cross-shaped unit cells, specifically, as... Figure 2As shown in (d) of this embodiment, in the mirror, the lattice constant, width, thickness, width of the side in the x direction, and width of the side in the y direction of the cross-shaped unit cell are a, w, t, b, and c respectively; the center of the resonator is the origin in the x direction. For the cross-shaped unit cell located at the center of the resonator, its lattice constant is a1, and the width of its side in the y direction is c1, where a1 < a and c1 < c; for the remaining cross-shaped unit cells in the resonator, the lattice constant a i , and the width c of the side in the y direction i , are respectively:

[0054]

[0055]

[0056] where i is the number of the cross-shaped unit cell in the resonator, and x i is the coordinate of the i-th cross-shaped unit cell in the resonator in the x direction; p(x) is a preset gradient function, and p(x) = 2x 3 - 3x 2 + 1. The remaining geometric parameters of the cross-shaped unit cells in the resonator are consistent with the corresponding geometric parameters of the cross-shaped unit cells in the mirror;

[0057] The gradient curves of the geometric parameters of each cross-shaped unit cell calculated based on the above gradient function are as shown in Figure 2 (c).

[0058] By changing the geometric parameters of the cross-shaped unit cells in the nanobeam 1, the frequencies of the acoustic third-order mode T and the optical first-order mode O can be correspondingly changed. In this embodiment, the geometric parameters of the cross-shaped unit cells in the nanobeam 1 satisfy that for the cross-shaped unit cell located at the center of the resonator, the frequencies of its acoustic third-order mode T and optical first-order mode O are respectively located in the phonon bandgap and photon bandgap of the mirrors at both ends of the nanobeam 1. Thus, after the two resonating modes are reflected by the mirrors, they can transition from the mirrors to the center of the resonator through several unit cells according to the geometric gradient function, and thus acoustic guided modes and optical guided modes can be simultaneously generated in the bandgap, and the displacement field of the acoustic guided mode and the electric field of the optical guided mode are highly localized in the resonator; in this embodiment, a = 600 nm, b = 180 nm, c = 180 nm, w = 700 nm, t = 220 nm; a1 = 480 nm, b1 = 180 nm; c1 = 126 nm, w1 = 700 nm, the frequency of the acoustic cavity mode is 5.69 GHz, and the frequency of the optical cavity mode is 198 THz.

[0059] In order to further improve the Q value of the nanoresonator, in this embodiment, the phonon bandgap of the mirrors at both ends of the nanobeam 1 is a complete bandgap; as shown in Figure 3As shown, the acoustic cavity mode resonant frequency of the nanobeam 1 provided in this embodiment is 5.69 GHz, located within the band gap of the reflector. Vibrations from the resonant cavity cannot be transmitted to the surrounding substrate 2 from any direction, significantly improving the Q value. In this embodiment, because the vibrations of the resonant cavity cannot be transmitted to the surrounding substrate 2, the Q value of this structure is limited only by the losses of the Akhierser mechanism, resulting in a Q value as high as 1.5 × 10⁻⁶ at room temperature. 4 Compared to existing room-temperature gigahertz nanoresonators, its Q value can be increased by 1 to 2 orders of magnitude; it is easy to understand that ultra-low temperature treatment can be used to further improve the Q value.

[0060] In a preferred embodiment, the nanobeam 1 and the surrounding substrate 2 are made of the same material and are etched from the same material. Specifically, both the nanobeam 1 and the surrounding substrate 2 are made of single-crystal silicon, which can support the propagation of sound waves and light waves at the same time and is easy to integrate into silicon-based chips. Optionally, in this embodiment, an electron beam is used to etch on the SOI silicon wafer to form a cross-shaped pattern of nanobeams and the surrounding substrate 2.

[0061] Optionally, in this embodiment, the material of the supporting substrate 3 is SiO2. m For example, SiO2.

[0062] Overall, the high-Q gigahertz nanoresonator provided in this embodiment has the following excellent characteristics:

[0063] (1) In this embodiment, a mechanical resonance of up to 5.69 GHz was achieved on silicon nanobeams using an optical system, with a Q value as high as 1.5 × 10⁻⁶ at room temperature. 4 .

[0064] (2) In this embodiment, the mirror unit cells at both ends of the silicon nanobeam have a wide full phonon bandgap near the resonant frequency domain, which prevents the mechanical vibration of the resonator from propagating to the substrate through the fixed end, greatly reducing the anchor point loss and effectively improving the Q value.

[0065] (3) In this embodiment, the 5.69 GHz acoustic cavity mode with ee symmetry (the modes are evenly symmetric in the mid-section of the nanobeam in the y and z directions respectively) is coupled with the ee symmetry optical cavity mode. Since the displacement field of the acoustic mode and the electric field of the optical mode are highly overlapping, an acousto-optic coupling rate of up to 775 kHz is achieved, which is easy to excite high-frequency phonon vibration.

[0066] (4) The high Q value gigahertz resonator provided in this embodiment has a simple structure, a single material, a very small size, and is easy to integrate. It can be directly fabricated using existing nanotechnology, which simplifies the device fabrication process.

[0067] Overall, the high-Q gigahertz resonator provided in this embodiment is a nanoscale high-frequency, high-Q resonator device that can overcome the shortcomings of previous resonators with low Q values ​​and difficulty in integration at GHz high frequencies. It has excellent performance of high frequency, high Q value and easy integration at room temperature, and can be applied to mobile 5G, WiFi, satellite and other communications, as well as ultra-high precision clocks and timing devices.

[0068] Example 2:

[0069] A resonance method based on the high-Q gigahertz resonator provided in Embodiment 1 above, such as... Figure 4 As shown, it includes:

[0070] Using frequency ω L A laser of frequency ω + Ω excites a high-Q gigahertz resonator, causing the laser to blue-shift to a frequency of ω, and simultaneously scattering phonons of frequency Ω in the form of Brillouin scattering, thereby achieving resonance;

[0071] Wherein, Ω is the acoustic cavity mode frequency of the nanobeam, and ω is the optical cavity mode frequency of the nanobeam; since the high Q-value gigahertz resonator provided in Example 1 can be coupled with the ee-symmetric 5.69 GHz acoustic cavity mode and the ee-symmetric 198 THz optical cavity mode to achieve an acousto-optic coupling rate of up to 775 kHz, it can be conveniently excited with a picosecond laser to excite high-frequency phonon vibrations. Therefore, as an optional implementation, in this embodiment, the laser used to excite phonons is specifically generated by a picosecond laser.

[0072] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-Q gigahertz resonator, characterized in that, include: A supporting substrate has a through-hole in the middle; A surrounding substrate disposed on the supporting substrate has openings in its surface; The cross-sectional area of ​​the opening is smaller than the cross-sectional area of ​​the through hole; And nanobeams, whose two ends are fixed to the inside of the opening; The nanobeam is composed of multiple cross-shaped unit cells arranged periodically. The cross-shaped unit cells at both ends of the nanobeam form mirrors at both ends, and the remaining cross-shaped unit cells form a resonant cavity. The nanobeam is symmetrical about the center of the resonant cavity. The cross-shaped unit cells are acousto-photonic crystals. The cross-shaped unit cells in the mirrors have the same geometric parameters; the geometric parameters of the cross-shaped unit cells include: lattice constant, width, thickness, width of the side in the x-direction and width of the side in the y-direction. The lattice constant and the width of the side in the y direction of the cross-shaped unit cell in the resonant cavity gradually change from the two ends of the resonant cavity to the center of the resonant cavity, and the other geometric parameters are consistent with those of the cross-shaped unit cell in the mirror. Wherein, the x-direction is the arrangement direction of the cross-shaped unit cells, and the y-direction is perpendicular to the x-direction; In the mirror, the lattice constant of the cross-shaped unit cell is: a The width of the side of the cross-shaped unit cell in the y direction is c The resonant cavity is centered at the origin in the x-direction, and a cross-shaped unit cell is located at the center of the resonant cavity with a lattice constant of . a 1. The width of its side in the y-direction is c 1, a 1< a , c 1< c The lattice constant of the remaining cruciform unit cells in the resonant cavity. a i and the width of the edge in the y direction. c i They are respectively: ； ； in, i This refers to the numbering of the cross-shaped unit cells in the resonant cavity. x i The first in the resonant cavity i A cross-shaped single cell x Coordinates of direction; p ( x ) is a preset gradient function, and p ( x )=2 x 3 -3 x 2 +1.

2. The high-Q gigahertz resonator as described in claim 1, characterized in that, The geometric parameters of the cross-shaped unit cell in the nanobeam satisfy the following: the frequency of the third acoustic mode T and the frequency of the first optical mode O of the cross-shaped unit cell located at the center of the resonant cavity are located in the phonon bandgap and photon bandgap of the mirrors at both ends of the nanobeam, respectively.

3. The high-Q gigahertz resonator as described in claim 2, characterized in that, The phonon band gaps of the mirrors at both ends of the nanobeam are complete band gaps.

4. The high-Q gigahertz resonator as described in claim 3, characterized in that, The nanobeams and the surrounding substrate are made of the same material and are etched from the same piece of material.

5. The high-Q gigahertz resonator as described in claim 4, characterized in that, The nanobeams and the surrounding substrate are etched from the same SOI silicon wafer.

6. The high-Q gigahertz resonator as described in claim 5, characterized in that, The material of the supporting substrate is SiO. m .

7. A resonance method based on the high-Q gigahertz resonator according to any one of claims 1 to 6, characterized in that, include: Utilizing frequency ω L = ω The high-Q gigahertz resonator is excited by a laser with a current of +Ω, causing the laser to undergo a blue shift to a frequency of... ω Simultaneously, it scatters phonons with a frequency of Ω in the form of Brillouin scattering, thereby achieving resonance; Where Ω is the eigenfrequency of the acoustic cavity mode of the nanobeam. ω The eigenfrequency of the optical cavity mode of the nanobeam is given.

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