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11 pages, 2592 KiB

Open AccessArticle

Hetero-Optomechanical Crystal Zipper Cavity for Multimode Optomechanics

by Ning Wu, Kaiyu Cui, Xue Feng, Fang Liu, Wei Zhang and Yidong Huang

Photonics 2022, 9(2), 78; https://doi.org/10.3390/photonics9020078 - 29 Jan 2022

Cited by 7 | Viewed by 3243

Abstract

Multimode optomechanics exhibiting several intriguing phenomena, such as coherent wavelength conversion, optomechanical synchronization, and mechanical entanglements, has garnered considerable research interest for realizing a new generation of information processing devices and exploring macroscopic quantum effect. In this study, we proposed and designed a [...] Read more.

Multimode optomechanics exhibiting several intriguing phenomena, such as coherent wavelength conversion, optomechanical synchronization, and mechanical entanglements, has garnered considerable research interest for realizing a new generation of information processing devices and exploring macroscopic quantum effect. In this study, we proposed and designed a hetero-optomechanical crystal (OMC) zipper cavity comprising double OMC nanobeams as a versatile platform for multimode optomechanics. Herein, the heterostructure and breathing modes with high mechanical frequency ensured the operation of the zipper cavity at the deep-sideband-resolved regime and the mechanical coherence. Consequently, the mechanical breathing mode at 5.741 GHz and optical odd mode with an intrinsic optical Q factor of 3.93 × 10⁵ were experimentally demonstrated with an optomechanical coupling rate g₀ = 0.73 MHz between them, which is comparable to state-of-the-art properties of the reported OMC. In addition, the hetero-zipper cavity structure exhibited adequate degrees of freedom for designing multiple mechanical and optical modes. Thus, the proposed cavity will provide a playground for studying multimode optomechanics in both the classical and quantum regimes. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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11 pages, 1261 KiB

Open AccessCommunication

Stability of the Discrete Time-Crystalline Order in Spin-Optomechanical and Open Cavity QED Systems

by Zhengda Hu, Xingyu Gao and Tongcang Li

Photonics 2022, 9(2), 61; https://doi.org/10.3390/photonics9020061 - 24 Jan 2022

Cited by 1 | Viewed by 2474

Abstract

Discrete time crystals (DTC) have been demonstrated experimentally in several different quantum systems in the past few years. Spin couplings and cavity losses have been shown to play crucial roles for realizing DTC order in open many-body systems out of equilibrium. Recently, it [...] Read more.

Discrete time crystals (DTC) have been demonstrated experimentally in several different quantum systems in the past few years. Spin couplings and cavity losses have been shown to play crucial roles for realizing DTC order in open many-body systems out of equilibrium. Recently, it has been proposed that eternal and transient DTC can be present with an open Floquet setup in the thermodynamic limit and in the deep quantum regime with few qubits, respectively. In this work, we consider the effects of spin damping and spin dephasing on the DTC order in spin-optomechanical and open cavity systems in which the spins can be all-to-all coupled. In the thermodynamic limit, it is shown that the existence of dephasing can destroy the coherence of the system and finally lead the system to its trivial steady state. Without dephasing, eternal DTC is displayed in the weak damping regime, which may be destroyed by increasing the all-to-all spin coupling or the spin damping. By contrast, the all-to-all coupling is constructive to the DTC in the moderate damping regime. We also focus on a model which can be experimentally realized by a suspended hexagonal boron nitride (hBN) membrane with a few spin color centers under microwave drive and Floquet magnetic field. Signatures of transient DTC behavior are demonstrated in both weak and moderate dissipation regimes without spin dephasing. Relevant experimental parameters are also discussed for realizing transient DTC order in such an hBN optomechanical system. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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15 pages, 808 KiB

Open AccessArticle

Squeezing Light via Levitated Cavity Optomechanics

by Guoyao Li and Zhang-Qi Yin

Photonics 2022, 9(2), 57; https://doi.org/10.3390/photonics9020057 - 22 Jan 2022

Cited by 3 | Viewed by 3260

Abstract

Squeezing light is a critical resource in both fundamental physics and precision measurement. Squeezing light has been generated through optical-parametric amplification inside an optical resonator. However, preparing the squeezing light in an optomechanical system is still a challenge for the thermal noise inevitably [...] Read more.

Squeezing light is a critical resource in both fundamental physics and precision measurement. Squeezing light has been generated through optical-parametric amplification inside an optical resonator. However, preparing the squeezing light in an optomechanical system is still a challenge for the thermal noise inevitably coupled to the system. We consider an optically levitated nano-particle in a bichromatic cavity, in which two cavity modes could be excited by the scattering photons of the dual tweezers, respectively. Based on the coherent scattering mechanism, the ultra-strong coupling between the cavity field and the torsional motion of nano-particle could be achieved for the current experimental conditions. With the back-action of the optically levitated nano-particle, the broad single-mode squeezing light can be realized in the bad cavity regime. Even at room temperature, the single-mode light can be squeezed for more than 17 dB, which is far beyond the 3 dB limit. The two-mode squeezing light can also be generated, if the optical tweezers contain two frequencies, one is on the red sideband of the cavity mode, the other is on the blue sideband. The two-mode squeezing can be maximized near the boundary of the system stable regime and is sensitive to both the cavity decay rate and the power of the optical tweezers. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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13 pages, 5064 KiB

Open AccessArticle

Force Dependent Quantum Phase Transition in the Hybrid Optomechanical System

by Lingchao Li and Jian-Qi Zhang

Photonics 2021, 8(12), 588; https://doi.org/10.3390/photonics8120588 - 18 Dec 2021

Cited by 1 | Viewed by 2344

Abstract

The optomechanics shows a great potential in quantum control and precise measurement due to appropriate mechanical control. Here we theoretically study the quantum phase transition in a hybrid atom-optomechanical cavity with an external force. Our study shows, in the thermodynamic limit, the critical [...] Read more.

The optomechanics shows a great potential in quantum control and precise measurement due to appropriate mechanical control. Here we theoretically study the quantum phase transition in a hybrid atom-optomechanical cavity with an external force. Our study shows, in the thermodynamic limit, the critical value of quantum phase transition between the normal phase and super-radiant phase can be controlled and modified by the external force via the tunable frequency of optomechanics, then a force dependent quantum phase transition can be achieved in our system. Moreover, this force dependent quantum phase transition can be employed to detect the external force variation. In addition, our numerical simulations illustrate the sensitivity of the external force measurement can be improved by the squeezing properties of the quantum phase transition. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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12 pages, 4580 KiB

Open AccessArticle

Numerical Analysis of Optical Trapping Force Affected by Lens Misalignments

by Hanlin Zhang, Wenqiang Li, Nan Li and Huizhu Hu

Photonics 2021, 8(12), 548; https://doi.org/10.3390/photonics8120548 - 2 Dec 2021

Cited by 6 | Viewed by 2514

Abstract

Geometrical optics approximation is a classic method for calculating the optical trapping force on particles whose sizes are larger than the wavelength of the trapping light. In this study, the effect of the lens misalignment on optical force was analyzed in the geometrical [...] Read more.

Geometrical optics approximation is a classic method for calculating the optical trapping force on particles whose sizes are larger than the wavelength of the trapping light. In this study, the effect of the lens misalignment on optical force was analyzed in the geometrical optics regime. We used geometrical optics to analyze the influence of off-axis placement and the tilt of the lens on the trapping position and stiffness in an optical trap. Numerical calculation results showed that lens tilting has a greater impact on the optical trap force than the off-axis misalignments, and both misalignments will couple with each other and cause a shift of the equilibrium point and the asymmetry of the optical trap stiffness in different ways. Our research revealed the asymmetry in optical traps caused by lens misalignment and can provide guidance for optimize lens placement in future experiments. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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13 pages, 2180 KiB

Open AccessArticle

Cooperative Molecular Rabi Splitting for Strong Coupling between a Plain Au Layer and an Azo-Dye

by Giuseppina Simone

Photonics 2021, 8(12), 531; https://doi.org/10.3390/photonics8120531 - 25 Nov 2021

Cited by 2 | Viewed by 2420

Abstract

Here, the experimental and numerical results provide evidence of strong coupling between an Au layer and an azo-dye. Strong coupling between the Au and a dye is not easy to observe, so a deep analysis for understanding the physics of the system is [...] Read more.

Here, the experimental and numerical results provide evidence of strong coupling between an Au layer and an azo-dye. Strong coupling between the Au and a dye is not easy to observe, so a deep analysis for understanding the physics of the system is carried on. After an accurate analysis of the reflectivity of the plain Au layer as well as after the chromophore adsorption, a hypothesis of strong coupling was advanced. The reflectivity dispersion of system polariton-exciton is characterized by an anti-crossing and two polaritons with a distance that raises with the concentration of the molecules until reaching a condition of saturation, as proof of a non-weak coupling. However, from one side the low-quality factor Q, from the other the optical characteristics of the dye, the strong coupling seems to contradict the achieved results. Then, a possible explanation of these results is that the collective vibrational level structure of the molecules plays a crucial role, and despite the poor conditions of coupling, the matching between the phonons and the excitons reaches an outstanding strength. The emission spectra permitted to characterize the vibrational status of the molecules coupled to the polaritons. Due to the dye adsorption, the surface plasmon frequency shifts, and the Stokes peak splits into two peaks, having a distance bigger than their line width. The strong effect of the collective mechanism of the molecules was described by a hybrid model. Finally, after proving and characterizing the strong coupling, the Raman scattering from such hybridized light-matter states was studied. The coherent nature of the vibro-polariton states increases the Raman scattering cross-section and indicates an enhancement mechanism due to the intrinsic properties of the molecules (e.g., polarizability). Since the light-matter interaction permits the property modulation of materials by confining to small volumes the light field for forming exciton-polariton states, these results provide insight into molecular science. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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9 pages, 428 KiB

Open AccessCommunication

Direct and Clean Loading of Nanoparticles into Optical Traps at Millibar Pressures

by Maryam Nikkhou, Yanhui Hu, James A. Sabin and James Millen

Photonics 2021, 8(11), 458; https://doi.org/10.3390/photonics8110458 - 20 Oct 2021

Cited by 11 | Viewed by 3106

Abstract

Nanoparticles levitated by optical fields under vacuum conditions have applications in quantum science, the study of nanothermodynamics and precision sensing. The existing techniques for loading optical traps require ambient conditions and often involve dispersion in liquids, which can contaminate delicate optics and lead [...] Read more.

Nanoparticles levitated by optical fields under vacuum conditions have applications in quantum science, the study of nanothermodynamics and precision sensing. The existing techniques for loading optical traps require ambient conditions and often involve dispersion in liquids, which can contaminate delicate optics and lead to enhanced optical absorption and heating. Here, we present a clean, dry and generic mechanism for directly loading optical traps at pressures down to 1 mbar, exploiting Laser Induced Acoustic Desorption and allowing for the rapid and efficient trapping of nanoparticles. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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16 pages, 1095 KiB

Open AccessArticle

Optical Amplification and Fast-Slow Light in a Three-Mode Cavity Optomechanical System without Rotating Wave Approximation

by Yan-Na Zhao, Tie Wang, Dong-Yang Wang, Xue Han, Shou Zhang and Hong-Fu Wang

Photonics 2021, 8(9), 384; https://doi.org/10.3390/photonics8090384 - 9 Sep 2021

Cited by 5 | Viewed by 2377

Abstract

We investigate the optical amplification of the output field and fast-slow light effect in a three-mode cavity optomechanical system without rotating wave approximation and discuss two ways of realizing the optical amplification effect. Resorting to the Coulomb coupling between the nanomechanical resonators, the [...] Read more.

We investigate the optical amplification of the output field and fast-slow light effect in a three-mode cavity optomechanical system without rotating wave approximation and discuss two ways of realizing the optical amplification effect. Resorting to the Coulomb coupling between the nanomechanical resonators, the asymmetric double optomechanically induced amplification effect can be achieved by utilizing the counterrotating term. Moreover, we find a remarkable optical amplification effect and observe the prominent fast-slow light effect at the singular point since the introduction of mechanical gain. Meanwhile, the transmission rate of the output field is increased by four orders of magnitude and the group delay time can reach in the order of

10^{5} μ s

. Our work is of great significance for the potential applications of optomechanically induced amplification in quantum information processing and quantum precision measurement. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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13 pages, 2035 KiB

Open AccessArticle

Optical Trapping of Sub−Micrometer Particles with Fiber Tapers Fabricated by Fiber Pulling Assisted Chemical Etching

by Chaoyang Ti, Yao Shen, Yiming Lei and Yuxiang Liu

Photonics 2021, 8(9), 367; https://doi.org/10.3390/photonics8090367 - 31 Aug 2021

Cited by 1 | Viewed by 2505

Abstract

Optical trapping of sub−micrometer particles in three dimensions has been attracting increasing attention in a wide variety of fields such as physics, chemistry, and biologics. Optical fibers that allow stable trapping of such particles are not readily available but beneficial in system integration [...] Read more.

Optical trapping of sub−micrometer particles in three dimensions has been attracting increasing attention in a wide variety of fields such as physics, chemistry, and biologics. Optical fibers that allow stable trapping of such particles are not readily available but beneficial in system integration and miniaturization. Here, we present a readily accessible batch fabrication method, namely fiber pulling assisted tubeless chemical etching, to obtain sharp tapered optical fibers from regular telecommunication single−mode fibers. We demonstrated the applications of such fiber tapers in two non−plasmonic optical trapping systems, namely single− and dual−fiber−taper−based trapping systems. We realized single particle trapping, multiple particle trapping, optical binding, and optical guiding with sub−micrometer silica particles. Particularly, using the dual fiber system, we observed the three−dimensional optical trapping of swarm sub−micrometer particles, which is more challenging to realize than trapping a single particle. Because of the capability of sub−micrometer particle trapping and the accessible batch fabrication method, the fiber taper−based trapping systems are highly potential tools that can find many applications in biology and physics. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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14 pages, 6135 KiB

Open AccessArticle

Characterizing Quantum Effects in Optically Induced Nanowire Self-Oscillations: Coherent Properties

by Jeong Ryeol Choi

Photonics 2021, 8(7), 237; https://doi.org/10.3390/photonics8070237 - 25 Jun 2021

Viewed by 1571

Abstract

Mechanical properties of metallic-nanowire self-oscillations are investigated through a coherent-state analysis. We focus on elucidating the time behavior of quantum energy in such oscillations, in addition to the analysis of fluctuations, evolution of eigenstates, and oscillatory trajectories. The quantum energy varies somewhat randomly [...] Read more.

Mechanical properties of metallic-nanowire self-oscillations are investigated through a coherent-state analysis. We focus on elucidating the time behavior of quantum energy in such oscillations, in addition to the analysis of fluctuations, evolution of eigenstates, and oscillatory trajectories. The quantum energy varies somewhat randomly at first, but, at a later time, it undergoes a stable periodical oscillation; the mean energy in the stabilized motion is large when the frequency of the driving force is resonated with that of the intrinsic oscillation of the nanowire. We confirmed that when the oscillatory amplitude is sufficiently low, the quantum energy is quite different from the classical one due to zero-point energy which appears in the quantum regime. Because the power in such an oscillation is typically ultra low, quantum effects in the nanowire oscillations are non-negligible. Detailed analysis for the evolution of the probability densities and their relation with the oscillation trajectories of the nanowire are also carried out. Characterizing quantum effects in the actual oscillatory motions and clarifying their difference from the classical ones are important in understanding nanowire self-oscillations. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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12 pages, 1001 KiB

Open AccessArticle

Robust Four-Wave Mixing and Double Second-Order Optomechanically Induced Transparency Sideband in a Hybrid Optomechanical System

by Huajun Chen

Photonics 2021, 8(7), 234; https://doi.org/10.3390/photonics8070234 - 24 Jun 2021

Cited by 1 | Viewed by 2083

Abstract

We theoretically research the four-wave mixing (FWM) and second-order sideband generation (SSG) in a hybrid optomechanical system under the condition of pump on-resonance and pump off-resonance, where an optomechanical resonator is coupled to another nanomechanical resonator (NR) via Coulomb interaction. Using the standard [...] Read more.

We theoretically research the four-wave mixing (FWM) and second-order sideband generation (SSG) in a hybrid optomechanical system under the condition of pump on-resonance and pump off-resonance, where an optomechanical resonator is coupled to another nanomechanical resonator (NR) via Coulomb interaction. Using the standard quantum optics method and input–output theory, we obtain the analytical solution of the FWM and SSG with strict derivation. According to the numerical simulations, we find that the FWM can be controlled via regulating the coupling strength and the frequency difference of the two NRs under different detuning, which also gives a means to determine the coupling strength of the two NRs. Furthermore, the SSG is sensitive to the detuning, which shows double second-order optomechanically induced transparency (OMIT) sidebands via controlling the coupling strength and frequencies of the resonators. Our investigation may increase the comprehension of nonlinear phenomena in hybrid optomechanics systems. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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Review

Jump to: Research

17 pages, 11858 KiB

Open AccessReview

Two-Membrane Cavity Optomechanics: Linear and Non-Linear Dynamics

by Paolo Piergentili, Riccardo Natali, David Vitali and Giovanni Di Giuseppe

Photonics 2022, 9(2), 99; https://doi.org/10.3390/photonics9020099 - 8 Feb 2022

Cited by 3 | Viewed by 2849

Abstract

In this paper, we review the linear and non-linear dynamics of an optomechanical system made of a two-membrane etalon in a high-finesse Fabry–Pérot cavity. This two-membrane setup has the capacity to modify on demand the single-photon optomechanical coupling, and in the linearized interaction [...] Read more.

In this paper, we review the linear and non-linear dynamics of an optomechanical system made of a two-membrane etalon in a high-finesse Fabry–Pérot cavity. This two-membrane setup has the capacity to modify on demand the single-photon optomechanical coupling, and in the linearized interaction regime to cool simultaneously two mechanical oscillators. It is a promising platform for realizing cavity optomechanics with multiple resonators. In the non-linear regime, an analytical approach based on slowly varying amplitude equations allows us to derive a consistent and full characterization of the non-linear displacement detection, enabling a truthful detection of membrane displacements much above the usual linear sensing limited by the cavity linewidth. Such a high quality system also shows a pre-synchronization regime. Full article

(This article belongs to the Special Issue Optomechanics: Science and Applications)

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