A magnetically controlled phonon frequency comb and apparatus and method for generating the same

Abstract

The application discloses a magnetostrictive phonon frequency comb and a generating device and method thereof, and belongs to the technical field of optical communication. The magnetostrictive phonon frequency comb is generated by a single mechanical mode magnetostrictive resonator under the driving of a double-pumping magnetic field. The frequency comb located at a near-resonance pumping position is steadily widened with the enhancement of a low-frequency pumping magnetic field, and the phonon frequency comb located at a position half of the near-resonance pumping position is switched multiple times with the enhancement of the low-frequency pumping magnetic field. The application proves the magnetostrictive phonon frequency comb based on a magnetostrictive macroscopic resonator. The basic magnetostrictive mechanical mode forms a comb-shaped spectrum under the action of the double-pumping magnetic field. The application provides a novel magneto-mechanical frequency comb for sensing, timing and metering applications. The magnetostrictive mechanical resonator has a macroscopic size, reaches a centimeter level, and is convenient to manufacture. Meanwhile, the application device does not need precise electrode contact and expensive precise laser detection, and the advantages greatly enhance the application scenarios of the phonon frequency comb.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical communications, and in particular relates to a magnetically controlled phonon frequency comb and a generating device and method thereof. Background Art

[0002] Optical frequency combs have had a profound impact, shaping fields from metrology to astronomy. An optical frequency comb is a broadband spectrum consisting of a series of discrete, equally spaced frequency components, manifesting itself in the frequency domain as a sequence of optical frequencies with equal frequency spacing. Optical frequency combs primarily focus on the electromagnetic wave band; expanding to lower frequencies requires the introduction of new systems. Phonons and photons are both bosons and share a high degree of similarity.

[0003] Phonon frequency combs, also known as acoustic or mechanical frequency combs, have been realized using piezoelectric-driven electromechanical resonators and cavity electromechanical devices based on Kerr-like nonlinearities. The phonon frequency combs they generate require direct contact between electrodes or precision laser detection. Their complexity, the requirement to design specific mode structures, very high threshold powers, and the possible need for additional laser sources limit the application of these systems.

[0004] To date, there have been no reports of using magnetic fields to manipulate magnetostrictive resonators to generate phonon frequency combs. Under a suitable bias static magnetic field, a magnetostrictive resonator has a very strong fundamental vibration mode. This mode easily enters a nonlinear vibration state when driven by a near-resonant pump magnetic field. At this time, the additional low-frequency pump interacts with the main vibration through a three-wave mixing mechanism, generating a series of equally spaced comb lines. In addition, when the near-resonant pump drives the resonator into a double-period bifurcation vibration, the low-frequency vibration driven by the low-frequency pump also interacts with the double-period vibration, generating a set of combs centered on the double-period vibration. This phonon frequency comb repeatedly switches between the two comb modes by half a comb tooth number as the low-frequency pump is enhanced. This precise half-tooth number manipulation of the phonon frequency comb based on a single mechanical mode has not yet been reported. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a magnetically controlled phonon frequency comb and a device and method for generating the same.

[0006] Technical solution: In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A magnetically controlled phonon frequency comb uses a single mechanical mode magnetostrictive resonator to generate three-wave mixing under the drive of a dual pump magnetic field to form a comb spectrum, thereby generating a phonon frequency comb.

[0008] Furthermore, a switchable phonon frequency comb is realized by suppressing period-doubling bifurcation, which can switch half the number of teeth at a constant comb tooth spacing.

[0009] Furthermore, when the near-resonance pump amplitude V p When it is low, the comb tooth spacing is equal to f s The frequency comb teeth cover a frequency band that varies with the low frequency pump V s The growth is steady.

[0010] Furthermore, when the near-resonance pump amplitude V p When the double period vibration threshold of the first vibration mode is increased, due to period doubling bifurcation and three-wave mixing, as the low-frequency pump amplitude V s With the increase of , additional comb-like structures appear.

[0011] A device for generating a magnetically controlled phonon frequency comb, characterized by comprising a magnetostrictive resonator measuring 15 mm × 4 mm × 25 μm, three induction coils for sensing, low-frequency pumping, and near-resonance pumping, respectively, an electromagnet, a function waveform generator, a lock-in amplifier, and a power amplifier; the lock-in amplifier and the power amplifier apply a low-frequency magnetic field; and the function waveform generator provides a sinusoidally varying field.

[0012] Furthermore, the induction coil converts the magnetic field excited by the resonator vibration into an electrical signal, which is input into a vector network analyzer or a phase-locked amplifier. The response measured by the phase-locked amplifier is then post-processed in the time and frequency domains to obtain the frequency domain response of the resonator.

[0013] Furthermore, a driving magnetic field is applied longitudinally:

[0014] H p =H dc +h p cos(2πf p t),

[0015] Among them, H p represents the total driving magnetic field applied; H dc represents the longitudinal static magnetic field, applied by the electromagnet; h p The sinusoidal changing field provided by the function waveform generator; f p For near-resonant pumping V p The frequency of t is the time. Apply a low-frequency magnetic field:

[0016] H s =h s cos(2πf s t),

[0017] Low frequency magnetic field H s Apply through a lock-in amplifier and a power amplifier; f sIndicates low-frequency pump V s Frequency; h s A low-frequency sinusoidal field provided to the lock-in amplifier and power amplifier; t represents time.

[0018] A method for generating a magnetically controlled phonon frequency comb is characterized by: using a magnetostrictive resonator with a single mechanical mode to generate a phonon frequency comb under the drive of a dual pump magnetic field, wherein the frequency comb located at a near-resonant pump frequency stably broadens as the low-frequency pump magnetic field increases, while the phonon frequency comb located at half the near-resonant pump frequency switches multiple times as the low-frequency pump magnetic field increases.

[0019] Furthermore, in the PD bifurcation state, applying a low-frequency pump V s , a comb spectrum appears near the resonance frequency, and the frequency band covered by the frequency comb increases with V s increases with the increase of f p The frequency comb generated at / 2 continuously switches between the two modes.

[0020] Furthermore, mode M1:f p / 2±nf s , Mode M2:(f p +f s ) / 2±nf s , where n is a positive integer; under the enhancement of the low-frequency pump magnetic field, the frequency comb switches between M1 and M2.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0022] The present invention discloses a device and method for generating a magnetically controlled phonon frequency comb based on a magnetostrictive mechanical resonator. A phonon frequency comb based on a magnetostrictive macroscopic resonator is proposed and experimentally demonstrated. The fundamental telescopic mechanical mode undergoes three-wave mixing under the action of a dual pump magnetic field, thereby forming a comb-like spectrum. Furthermore, a new switchable phonon frequency comb is proposed that suppresses period-doubling bifurcations and can switch half the number of teeth at a constant comb tooth spacing. Experiments show that the formation, evolution, and switching of the phonon frequency comb in the period-doubling bifurcation state are related to the Duffing nonlinear mechanism.

[0023] The discovery of the present invention provides a new type of magneto-mechanical frequency comb for sensing, timing and metering applications. The magnetostrictive mechanical resonator used is macroscopic in size, reaching the centimeter level, so it is easy to manufacture. At the same time, the device of the invention does not require precise electrode contact or expensive precision laser detection. These advantages greatly enhance the application scenarios of the phonon frequency comb. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a conceptual diagram of the formation and evolution of the magnetic phonon frequency comb;

[0025] Figure 2 It is the magneto-mechanical phonon frequency comb experimental setup;

[0026] Figure 3 (a) In the static magnetic field H with different strengths dc The first mechanical resonant frequency and S of the resonator are measured under 11 Reflection coefficient value. The green dashed line indicates the bias static magnetic field H corresponding to the subsequent experiment. dc =14.3Oe. (b) The measured resonator at H dc =S at 14.3Oe 11 Spectrum. The inset shows the numerical finite element simulation of the first vibration mode, and the color represents the stress distribution. (c) Increasing the pump voltage V near the resonance frequency p Contour plot of the mechanical resonator response when the pump voltage V is low. The color bar indicates the amplitude in dBV. (d) Three typical spectra extracted from (c), i.e., s =0, bias static magnetic field H dc =14.3Oe single cycle oscillation (V p =5V), PD bifurcation (V p =15V) and chaos (V p =30V).

[0027] Figure 4 The resonator is in the double period bifurcation vibration state, and the spectrum changes with the low frequency pump voltage V s Changes in intensity.

[0028] Figure 5 (a) Continuous sweep spectrum at half the near-resonant pump frequency (75kHz). (b) The three arrows in the figure mark the changes in the three comb teeth amplitudes. Δ = ff p =0, 0.1, -0.1kHz. The two background colors represent the regions where the M1 and M2 modes exist, respectively.

[0029] Figure 6 The evolution of the comb structure at half the near-resonant pump frequency (75kHz) at different low-frequency pump voltages measured under detuned conditions. (a) V s =0mV,(c)V s =200mV,(e)V s =400mV. (b), (d), (f) are the amplitude changes of the three teeth marked by the three arrows in Figures (a), (c), and (e). δ = ff p / 2 = 0, 0.1, -0.1kHz. The two background colors represent the areas where the M1 and M2 modes exist, respectively. DETAILED DESCRIPTION

[0030] The present invention will be further illustrated below with reference to specific examples. The examples are implemented based on the technical solutions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0031] Example 1

[0032] This embodiment provides a magnetically controlled phonon frequency comb, which uses a magnetostrictive resonator with a single mechanical mode to generate three-wave mixing under the drive of a dual pump magnetic field to form a comb spectrum, thereby generating a phonon frequency comb.

[0033] By suppressing period-doubling bifurcation, a switchable phonon frequency comb is realized, which can switch the number of half teeth at a constant comb tooth spacing. p When it is lower, the tooth spacing is equal to f s The frequency comb teeth cover a frequency band that varies with the low frequency pump V s When the near-resonance pump V p When the double period vibration threshold of the first vibration mode is increased, due to period doubling bifurcation and three-wave mixing, as the low-frequency pump V s With the increase of , additional comb-like structures appear.

[0034] like Figure 1 As shown, it is a mechanical system with a single vibration mode f0, which is excited by applying two pump magnetic fields, i.e., the frequency is f p (≈f0) near-resonant pump V p and frequency f s The weaker low-frequency pump V s , the system will enter the nonlinear dynamic region.

[0035] When the near-resonant pump V p When it is lower, the tooth spacing is equal to f s The frequency comb teeth cover a frequency band that varies with the low frequency pump V s The frequency comb increases steadily with the increase of mf p ±nf s (m=0,1,2…,n=0,1,2…) form, where mf p represents the order and center of the mth comb, n and f s Indicates the nth comb tooth and comb tooth spacing, such as Figure 1 Shown in the dotted box.

[0036] When the near-resonant pump V p When the double period vibration threshold of the first vibration mode is increased, due to period doubling bifurcation and three-wave mixing, as the low-frequency pump V s With the increase of p / 2±nf s(Spectrum 2). At a constant near-resonant pump voltage V p Next, continue to increase the low-frequency pump V s , comb structure (2m+1)f p / 2±nf s Convert to (2m+1)(f p +f d ) / 2±nf s (Spectrum 4), and is accompanied by a brief superposition (Spectrum 3). In this process, the p The frequency band covered by the phonon frequency comb centered on α is steadily growing.

[0037] Example 2

[0038] This embodiment provides a device for generating a magnetically controlled phonon frequency comb. The structure of the device is as follows: Figure 2 As shown, the device consists of a magnetostrictive resonator measuring 15 mm × 4 mm × 25 μm, three induction coils for sensing, low-frequency pumping, and near-resonant pumping, respectively; an electromagnet for applying a static magnetic field; a function waveform generator; a lock-in amplifier; and a power amplifier. The three induction coils are arranged outside the resonator, extending from the inside out, for sensing, low-frequency pumping, and near-resonant pumping, respectively. The low-frequency magnetic field is applied via the lock-in amplifier and power amplifier; the function waveform generator provides a sinusoidally varying field.

[0039] The resonator of this embodiment is made of AYFA-M iron-based amorphous alloy material (Metglas) produced by Qingdao Yunlu Advanced Materials Technology Co., Ltd. The resonator is processed and cut using fiber laser equipment to a size of 15 mm × 4 mm × 25 μm.

[0040] like Figure 2 As shown in the figure, three coils are set outside the resonator along the length from the inside to the outside, which are used for sensing, low-frequency pumping and near-resonance pumping respectively. The driving magnetic field is applied longitudinally:

[0041] H p =H dc +h p cos(2πf p t),

[0042] Among them, H p represents the total driving magnetic field applied; H dc represents the longitudinal static magnetic field, applied by the electromagnet; h p The sinusoidal changing field provided by the function waveform generator; f p For near-resonant pumping V p is the frequency; t is the time.

[0043] Another low-frequency magnetic field is:

[0044] Hs =h s cos(2πf s t),

[0045] Low frequency magnetic field H s Apply through a lock-in amplifier and a power amplifier; f s Indicates low-frequency pump V s Frequency; h s A low-frequency sinusoidal field provided to the lock-in amplifier and power amplifier; t represents time.

[0046] The induction coil converts the magnetic field generated by the resonator's vibration into an electrical signal, which is then fed into a vector network analyzer (VNA) or a lock-in amplifier. Using LabView software, the response measured by the lock-in amplifier is post-processed in the time and frequency domains to obtain the frequency domain response of the mechanical resonator.

[0047] Example 3

[0048] This embodiment provides a method for generating a magnetically controlled phonon frequency comb. A magnetostrictive resonator with a single mechanical mode is used to generate a phonon frequency comb under the drive of a dual pump magnetic field. The frequency comb located near the resonant pump frequency steadily broadens as the low-frequency pump magnetic field increases, while the phonon frequency comb located at half the near-resonant pump frequency switches multiple times as the low-frequency pump magnetic field increases.

[0049] The resonator is placed in the solenoid connected to VNA-PORT1, and the resonant frequency and vibration amplitude of the resonator are measured under different axial static magnetic fields. The resonant frequency f0 of the longitudinal vibration is related to the Young's modulus of the resonator Metglass material, and the value of the Young's modulus can be changed by applying a static magnetic field. The experimental results are shown in Figure 2. Figure 3 As shown in (a), the resonant frequency increases from 145kHz to 159kHz as the magnetic field increases. When the external magnetic field is in the range of 10-20Oe, the resonant frequency changes rapidly with the magnetic field.

[0050] The present invention selects a magnetic field that the resonator is sensitive to changes in the external environment, namely 14.3Oe, as the bias magnetic field for subsequent experiments. The present invention extracts the S 11 Reflection coefficient spectrum, such as Figure 3 (b) It can be seen that the mechanical quality factor of the first mechanical mode f0=150.4kHz is 109. Figure 3 The inset in (b) shows the numerical finite element simulation of this vibration mode.

[0051] The driving frequency f p Set it to 150kHz near f0 and gradually increase the pump voltage V p , the mechanical resonator will undergo a period-doubling (PD) bifurcation until chaos occurs. Figure 3(c) is the frequency and pump voltage V p The measured spectrum on the plane is scanned, and initially only f = f is observed. p = a peak at 150kHz. When the pump voltage increases to above 9V, PD bifurcation occurs, and the response peak corresponds to (2m–1)f p / 2=(2m–1)75kHz, where m is a positive integer. Further increasing the pump voltage to 20V, the resonant cavity enters the chaotic region. The typical spectra of periodic motion, PD bifurcation, and chaotic state extracted from 3(c) are shown in Figure 3(c). Figure 3 (d) corresponds to V p =5V, 15V and 30V.

[0052] Next, in the PD bifurcation state, apply f s =200Hz low frequency pump V s . Figure 4 For different V s Measured spectrum under . Note that a comb spectrum appears near the resonance frequency, which is described as f p ±nf s . And the frequency band covered by the frequency comb varies with V s And at f p The frequency comb generated at / 2 continuously switches between two modes, mode M1:f p / 2±nf s , Mode M2:(f p +f s ) / 2±nf s , where n is a positive integer. The comb widths of M1 and M2 are the same, but the main peaks are 100Hz apart. At the junction of M1 and M2, there is a short mixed comb wave f p / 2±nf s / 2. Figure 5 (a) Figure 4 The corresponding graph, where Δ = f – f p / 2. The different dashed lines correspond to Figure 4 It can be found that under this external parameter, the frequency comb switches between M1 and M2 many times. In addition, when f p When there is a small detuning between f0 and f1, the number of teeth is asymmetric due to the asymmetry of the comb teeth amplitude and its decay rate. Figure 5 In (a), when f p When –f0<0, the high-frequency side comb teeth have a larger amplitude and a larger number of comb teeth. Figure 5 The amplitude changes of the three comb teeth shown in (a) and Figure 5 (b) is marked with arrows (75kHz, 75.1kHz, 74.9kHz). The results show that when f pWhen the / 2 component (corresponding to M1) is suppressed, f p / 2+f s The / 2 (corresponding to M2) component increases. When the values ​​of the two components are equal, modes M1 and M2 are superimposed.

[0053] In order to confirm the conditions for combing and mode switching at the PD bifurcation, the present invention tunes the resonant cavity in the bifurcation state. The Duffing phenomenon shows that at a larger V p Under low voltage, the frequency response will be skewed, and the multi-valued response curve will cause jump phenomenon. p =10V, low frequency pump voltage V s = 0, the system is in f p The response results near / 2 are as follows Figure 6 (a). When f p When the frequency is between 148.8 and 155.3 kHz, PD bifurcation occurs. Figure 6 As shown in the blue spectrum of (b), at V s = 0, the response f p The amplitude of the / 2 component (δ=0) varies with f p changes with the change of f, showing the typical spring softening effect: p Start from 148kHz and increase slowly. p =148.8kHz jumps from –104 (noise) to –61dBV, and then gradually decreases to noise. p / 2 on both sidesδ=f–f p / 2=±0.1 components. The present invention can see that these components have no response when no low-frequency pump magnetic field is applied.

[0054] Figure 6 (c) is V s = 200mV, we can see that the frequency comb switches between M1 and M2. Figure 6 As shown in (d), the amplitude of the component δ = 0, ±0.1 changes with f p The intensity of the δ=0 component (corresponding to M1) is exchanged with the intensity of the δ=±0.1 component (corresponding to M2). s =400mV, if Figure 6 As shown in (e) and (f), the switching frequency of the phonon frequency comb is higher. In summary, with the enhancement of low-frequency pumping, the spring softening effect caused by the PD bifurcation effect is destroyed.

[0055] In summary, the present invention uses a single-mechanical-mode magnetostrictive resonator driven by dual pump magnetic fields to generate a phonon frequency comb. The frequency comb near the resonant pump frequency steadily broadens as the low-frequency pump magnetic field increases, while the phonon frequency comb near half the resonant pump frequency undergoes multiple switching cycles as the low-frequency pump magnetic field increases. This invention not only provides a device and method for generating a magnetically controlled phonon frequency comb, but also demonstrates that the mode switching operation of this frequency comb can be extended to other nonlinear devices, enriching the means for precisely controlling frequency combs.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A magnetically controlled phonon frequency comb, characterized by: A magnetostrictive resonator with a single mechanical mode undergoes three-wave mixing under the drive of a dual pump magnetic field, forming a comb spectrum, thereby generating a phonon frequency comb; by suppressing the period-doubling bifurcation, a switchable phonon frequency comb is achieved, which can switch half the number of comb teeth at a constant comb tooth spacing; when the near-resonant pump amplitude is V p When it is lower, the tooth spacing is equal to f s The frequency comb teeth cover a frequency band that varies with the low-frequency pump amplitude. V s The steady growth of f s Indicates the frequency of low-frequency pump; when the near-resonance pump amplitude V p When the double period vibration threshold of the first vibration mode is increased, due to period doubling bifurcation and three-wave mixing, the low-frequency pump amplitude increases. V s With the increase of , additional comb-like structures appear.

2. A method for generating a magnetically controlled phonon frequency comb according to claim 1, characterized in that: A magnetostrictive resonator with a single mechanical mode generates a phonon frequency comb under the drive of a dual pump magnetic field. The frequency comb at the near-resonant pump frequency steadily broadens with the increase of the low-frequency pump magnetic field, while the phonon frequency comb at half the near-resonant pump frequency switches multiple times with the increase of the low-frequency pump magnetic field.

3. The method for generating a magnetically controlled phonon frequency comb according to claim 2, wherein: In the period-doubling bifurcation state, low-frequency pumping is applied V s , near resonance frequency f p A comb spectrum appears at the position where the frequency comb covers a wider frequency band. V s increases with the increase of f p The frequency comb generated at / 2 switches continuously between two modes: Mode M1: f p / 2± nf s , Mode M2:( f p + f s ) / 2± nf s , in, n is a positive integer; under the enhancement of the low-frequency pump magnetic field, the frequency comb switches between M1 and M2, f p is the frequency of the near-resonant pump.

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