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为了实现声子在两个悬臂梁之间的相干传输,囚禁光的功率被周期性调制
$ P\left(t\right)={P}_{0}+ {P}_{d}\cos\left({\omega }_{d}t\right) $ ,从而使得悬臂梁1处于一个周期性振荡的光势阱中。此时,悬臂梁的位移可以写为${x}_{j}\left(t\right)\approx Re\left[{a}_{j}\left(t\right){{\rm{e}}}^{-i{\omega }_{j}t}\right]$ ,其中$ {a}_{j}\left(t\right) $ 代表悬臂梁j的振动幅度。在悬臂梁振幅变化比较缓慢的情况下,可以得到:$$ \left[\begin{array}{cc}i\dfrac{d}{{\rm{d}}t}+\mathrm{\varepsilon }\left(t\right)+i\dfrac{{\gamma }_{1}}{2}& \dfrac{{\omega }_{2}}{{\omega }_{1}\left({P}_{0}\right)}\dfrac{{\Delta }_{0}}{2}\\ \dfrac{{\Delta }_{0}}{2}& i\dfrac{d}{{\rm{d}}t}+i\dfrac{{\gamma }_{2}}{2}\end{array}\right]\left[\begin{array}{c}{a}_{1}\left(t\right)\\ {a}_{2}\left(t\right)\end{array}\right]=0\text{} $$ (1) 式中:驱动场
$\mathrm{\varepsilon }\left(t\right)={A}_{d}\sin\left({\omega }_{d}t\right)$ 的幅度为${A}_{d}=g{P}_{d}/2{\omega }_{1}\left({P}_{0}\right)$ 。作变换${a}_{1}\left(t\right)=\dfrac{{\omega }_{2}}{{\omega }_{1}\left({P}_{0}\right)}{b}_{1}\left(t\right){{\rm{e}}}^{-i\int \mathrm{\varepsilon }\left(t\right){\rm{d}}t}$ 和$ {a}_{2}\left(t\right)={b}_{2}\left(t\right) $ ,可以得到:$$ \left[\begin{array}{cc}-i\dfrac{d}{{\rm{d}}t}-i\dfrac{{\gamma }_{1}}{2}& \dfrac{{\Delta }_{0}}{2}{{\rm{e}}}^{i\int {\mathrm{\varepsilon }}_{0}+{A}_{d}\sin\left({\omega }_{d}t\right){\rm{d}}t}\\ \dfrac{{\Delta }_{0}}{2}{{\rm{e}}}^{-i\int {\mathrm{\varepsilon }}_{0}+{A}_{d}\sin\left({\omega }_{d}t\right){\rm{d}}t}& -i\dfrac{d}{{\rm{d}}t}-i\dfrac{{\gamma }_{1}}{2}\end{array}\right]\left[\begin{array}{c}{b}_{1}\left(t\right)\\ {b}_{2}\left(t\right)\end{array}\right]=0\text{} $$ (2) 其中,驱动偏置
$ {\mathrm{\varepsilon }}_{0}={\omega }_{1}\left({P}_{0}\right)-{\omega }_{2} $ 。这表明在驱动场作用下,两个悬臂梁间的有效耦合强度变为:${\Delta }_{eff}= $ $ {\Delta }_{0}{\displaystyle\sum }_{n}{\left(\pm 1\right)}^{n}{J}_{n}\left(\dfrac{{A}_{d}}{{\omega }_{d}}\right)\mathrm{e}\mathrm{x}\mathrm{p}[\pm i({\mathrm{\varepsilon }}_{0}-n{\omega }_{d}\left)t\right]$ ,其中$ {J}_{n} $ 表示$ n $ 阶第一类贝塞尔函数[16-17]。在$ {\mathrm{\varepsilon }}_{0}-n{\omega }_{d}=0 $ (n为整数)时,两个悬臂梁可以实现共振的耦合。当驱动频率非常高时($ {\omega }_{d}\gg {\Delta }_{0} $ ),忽略非共振项的作用,可以得到悬臂梁的有效耦合强度$ {\Delta }_{eff}\approx {\Delta }_{0}\left|{J}_{n}\left({A}_{d}/{\omega }_{d}\right)\right| $ 。
Landau-Zenner-Stückelberg interference of phonons in a cavity optomechanical systems (Invited)
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摘要: 微纳机械振子被认为是一种发展片上信号处理器件的理想平台,可以将各种不同的物理场转换为振动声子,实现基于声子的片上信息处理。其中,控制声子在不同机械振子间的传输是实现声子信息处理的关键。通过将两个机械振子耦合构造两模机械系统,目前虽然已经实现了不同杂化模式间声子的相干传输,但是依然缺乏直接调控两个独立机械振子有效耦合强度的方法。为此,文中在腔光力系统中开发了基于朗道-芝诺-斯塔博格(Landau-Zenner-Stückelberg,LZS)干涉的相干声子操控方法。在利用光学囚禁作用调控两个机械振子振动模式杂化的基础上,通过对囚禁光进行调制施加参量驱动场,使得系统周期性地穿过免交叉点实现了声子的LZS干涉。研究表明:在满足共振条件下,利用LZS干涉可以实现声子在两个独立机械振子间的相干传递。笔者的研究为实现声子信息在实空间的高效传递提供了一个有效途径。
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关键词:
- 相干声子操控 /
- 朗道-芝诺-斯塔博格干涉 /
- 腔光力系统 /
- 耦合机械振子 /
- 声子信息处理
Abstract: Micro-nano mechanical resonators are believed to be an ideal platform for developing on-chip signal processing devices, in which various kinds of physical fields can be transduced to mechanical phonons for phonon-based information processing. In such a strategy, control of phonon transferring between different mechanical resonators is essential for phonon-based information processing. By coupling two mechanical resonators for a two-mode mechanical system, although coherent phonon transferring between hybridized mechanical modes has been achieved recently, direct control over the effective coupling between disparate mechanical resonators is still desirable. Therefore, coherent control of phonons through Landau-Zenner-Stückelberg (LZS) interference was developed in an optomechanical system in this paper. The hybridization between two mechanical resonators was mediated using the effect of optical trapping, and a parametric driving field was applied through modulating the optical trap so that the system transvered the avoided-crossing point periodically to realize the LZS interference of phonons. The studies demonstrate that coherent phonon transferring between two disparate mechanical resonators can be achieved through the LZS interference when the on-resonance condition is satisfied. The authors' research provides an efficient scheme for high-efficient transferring of phonon-based information in real space. -
图 1 (a)实验装置示意图 (为了对单个悬臂梁进行测量和控制,光束半径被微透镜聚焦到了约3 μm);(b)不同囚禁功率下耦合悬臂梁的热振动功率密度谱
Figure 1. (a) Schematic diagram of experimental setup(In order to detect and control only one cantilever, the beam radius is focused to 3 μm by two micro-lenses);(b) Thermal oscillation spectral density of the coupled cantilevers at various trapping powers
图 2 (a)一阶LZS干涉导致的声子振荡;(b)声子振荡频率与驱动幅度的关系(实验测量结果(黑点)与理论计算的
$ {\Delta }_{eff} $ (灰色实线)相符)Figure 2. (a) Phonon oscillation caused by the first-order LZS interference;(b) Relation between the driving amplitude and frequency of phonon oscillation(Experimental measurements (black dots) agree well with theoretical results calculated from
$ {\Delta }_{eff} $ (gray line))图 4 基于零阶LZS干涉的声子振荡。共振条件下测量得到的(a)悬臂梁1和(b)悬臂梁2的振幅与数值计算得到的(c)悬臂梁1和(d)悬臂梁2的振幅
Figure 4. Phonon oscillation based on the zero-order LZS interference. The experimentally measured amplitudes of (a) cantilever 1 and (b) cantilever 2,and the numerical calculated amplitudes of (c) cantilever 1 and (b) cantilever 2 at the resonant condition
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[1] Bagci T, Simonsen A, Schmid S, et al. Optical detection of radio waves through a nanomechanical transducer [J]. Nature, 2014, 507(7490): 81-85. doi: 10.1038/nature13029 [2] Palomaki T A, Harlow J W, Teufel J D, et al. Coherent state transfer between itinerant microwave fields and a mechanical oscillator [J]. Nature, 2013, 495(7440): 210-214. doi: 10.1038/nature11915 [3] Chan J, Alegre T P, Safavi-Naeini A H, et al. Laser cooling of a nanomechanical oscillator into its quantum ground state [J]. Nature, 2011, 478(7367): 89-92. doi: 10.1038/nature10461 [4] O'Connell A D, Hofheinz M, Ansmann M, et al. Quantum ground state and single-phonon control of a mechanical resonator [J]. Nature, 2010, 464(7289): 697-703. doi: 10.1038/nature08967 [5] Okamoto H, Gourgout A, Chang C Y, et al. Coherent phonon manipulation in coupled mechanical resonators [J]. Nature Physics, 2013, 9(8): 480-484. doi: 10.1038/nphys2665 [6] Zhu D, Wang X H, Kong W C, et al. Coherent phonon rabi oscillations with a high-frequency carbon nanotube phonon cavity [J]. Nano Letters, 2017, 17(2): 915-921. doi: 10.1021/acs.nanolett.6b04223 [7] Tian T, Lin S, Zhang L, et al. Perfect coherent transfer in an on-chip reconfigurable nanoelectromechanical network [J]. Phys Rev B, 2020, 101(17): 174303. doi: 10.1103/PhysRevB.101.174303 [8] Zhang Z Z, Song X X, Luo G, et al. Coherent phonon dynamics in spatially seperated graphene mechanical resonators [J]. PNAS, 2020, 117(11): 5582. doi: 10.1073/pnas.1916978117 [9] Landau L D. A theory of energy transfer on collisions [J]. Phys Z Sowjet, 1932, 1(88): 52-59. [10] Zener C. Non-adiabatic crossing of energy levels [C]// Proceedings of the Royal Society of London, 1932, 137(833): 696-702. [11] Shevchenko S N, Ashhab S, Nori F. Landau–Zener–Stückelberg interferometry [J]. Physics Reports, 2010, 492(1): 1-30. doi: 10.1016/j.physrep.2010.03.002 [12] Ashhab S, Johansson J R, Zagoskin A M, et al. Two-level systems driven by large-amplitude fields [J]. Physical Review A, 2007, 75(6): 063414. doi: 10.1103/PhysRevA.75.063414 [13] Yang Z X, Zhang Y M, Zhou Y X, et al. Phase-sensitive Landau-Zener-Stückelberg interference in superconducting quantum circuit [J]. Chinese Physics B, 2021, 30(2): 024212. doi: 10.1088/1674-1056/abd753 [14] Kervinen M, Ramirez-Munoz J E, Valimaa A, et al. Landau-Zener-Stückelberg interference in a multimode electromechanical system in the quantum regime [J]. Phys Rev Lett, 2019, 123(24): 240401. doi: 10.1103/PhysRevLett.123.240401 [15] Oliver W D, Yu Y, Lee J, et al. Mach-Zehnder interferometry in a strongly driven superconducting qubit [J]. Science, 2005, 310(5754): 1653-1657. doi: 10.1126/science.1119678 [16] Fu H, Gong Z C, Yang L P, et al. Coherent optomechanical switch for motion transduction based on dynamically localized mechanical modes [J]. Phys Rev Appl, 2018, 9(5): 054024. doi: 10.1103/PhysRevApplied.9.054024 [17] Zhou L, Yang S, Liu Y X, et al. Quantum Zeno switch for single-photon coherent transport [J]. Phys Rev A, 2009, 80(6): 062109. doi: 10.1103/PhysRevA.80.062109