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1. Optomechanical crystal with bound states in the continuum

   https://doi.org/10.1038/s41467-022-30965-6  

   Liu, Shengyan; Tong, Hao; Fang, Kejie (December 2022, Nature Communications)

   Abstract Chipscale micro- and nano-optomechanical systems, hinging on the intangible radiation-pressure force, have shown their unique strength in sensing, signal transduction, and exploration of quantum physics with mechanical resonators. Optomechanical crystals, as one of the leading device platforms, enable simultaneous molding of the band structure of optical photons and microwave phonons with strong optomechanical coupling. Here, we demonstrate a new breed of optomechanical crystals in two-dimensional slab-on-substrate structures empowered by mechanical bound states in the continuum (BICs) at 8 GHz. We show symmetry-induced BIC emergence with optomechanical couplings up to g /2 π ≈ 2.5 MHz per unit cell, on par with low-dimensional optomechanical crystals. Our work paves the way towards exploration of photon-phonon interaction beyond suspended microcavities, which might lead to new applications of optomechanics from phonon sensing to quantum transduction. 

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2. High photon-phonon pair generation rate in a two-dimensional optomechanical crystal

   https://doi.org/10.1038/s41467-025-57948-7  

   Mayor, Felix M; Malik, Sultan; Primo, André G; Gyger, Samuel; Jiang, Wentao; Alegre, Thiago_P M; Safavi-Naeini, Amir H (December 2025, Nature Communications)

   Abstract Integrated optomechanical systems are a leading platform for manipulating, sensing, and distributing quantum information, but are limited by residual optical heating. Here, we demonstrate a two-dimensional optomechanical crystal (OMC) geometry with increased thermal anchoring and a mechanical mode at 7.4 GHz, well aligned with the operation range of cryogenic microwave hardware and piezoelectric transducers. The eight times better thermalization than current one-dimensional OMCs, large optomechanical coupling rates,g₀/2π  ≈  880 kHz, and high optical quality factors,Q_opt = 2.4 × 10⁵, allow ground-state cooling (n_m = 0.32) of the acoustic mode from 3 K and entering the optomechanical strong-coupling regime. In pulsed sideband asymmetry measurements, we show ground-state operation (n_m < 0.45) at temperatures below 10 mK, with repetition rates up to 3 MHz, generating photon-phonon pairs at  ≈ 147 kHz. Our results extend optomechanical system capabilities and establish a robust foundation for future microwave-to-optical transducers with entanglement rates exceeding state-of-the-art superconducting qubit decoherence rates. 

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3. Ultracompact 4H-silicon carbide optomechanical resonator with f _m  ·  Q _m exceeding 10 ¹³   Hz

   https://doi.org/10.1364/PRJ.567674  

   Liu, Yuncong; Sun, Wenhan; Abiri, Hamed; Feng, Philip X-L; Li, Qing (September 2025, Photonics Research)

   Silicon carbide (SiC) has great potential for optomechanical applications due to its outstanding optical and mechanical properties. However, challenges associated with SiC nanofabrication have constrained its adoption in optomechanical devices, as embodied by the considerable optical loss or lack of integrated optical access in existing mechanical resonators. In this work, we overcome such challenges and demonstrate a low-loss, ultracompact optomechanical resonator in an integrated 4H-SiC-on-insulator (4H-SiCOI) photonic platform for the first time, to our knowledge. Based on a suspended 4.3-μm-radius microdisk, the SiC optomechanical resonator features low optical loss (<1  dB/cm), a high mechanical frequencyf_mof 0.95×10⁹  Hz, a mechanical quality factorQ_mof 1.92×10⁴, and a footprint of <1×10⁻⁵  mm². The correspondingf_m·Q_mproduct is estimated to be 1.82×10¹³  Hz, which is among the highest reported values of optomechanical cavities tested in ambient environment at room temperature. In addition, the strong optomechanical coupling in the SiC microdisk enables coherent regenerative optomechanical oscillations at a threshold optical dropped power of 14 μW, which also supports efficient harmonic generation at increased power levels. With such competitive performance, we envision a range of chip-scale optomechanical applications to be enabled by the low-loss 4H-SiCOI platform. 

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4. Deeply subwavelength integrated excitonic van der Waals nanophotonics

   https://doi.org/10.1364/OPTICA.499059  

   Ling, Haonan; Manna, Arnab; Shen, Jialiang; Tung, Ho-Ting; Sharp, David; Fröch, Johannes; Dai, Siyuan; Majumdar, Arka; Davoyan, Artur R. (January 2023, Optica)

   The wave nature of light sets a fundamental diffraction limit that challenges confinement and control of light in nanoscale structures with dimensions significantly smaller than the wavelength. Here, we study light–matter interaction in van der Waals MoS₂nanophotonic devices. We show that light can be coupled and guided in structures with dimensions as small as ≃λ/16 (∼60nm at 1000 nm excitation wavelength), while offering unprecedented optical field confinement. This deep subwavelength optical field confinement is achieved by exploiting strong lightwave dispersion in MoS₂. We further study the performance of a range of nanophotonic integrated devices via far- and near-field measurements. Our near-field measurements reveal detailed imaging of excitation, evolution, and guidance of fields in nanostructured MoS₂, whereas our far-field study examines light excitation and coupling to highly confined integrated photonics. Nanophotonics at a fraction of a wavelength demonstrated here could dramatically reduce the size of integrated photonic devices and opto-electronic circuits with potential applications in optical information science and engineering. 

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5. Ultrafast Optomechanical Strain in Layered GeS

   https://doi.org/10.1021/acs.nanolett.2c05048  

   Luo, Duan; Zhang, Baiyu; Sie, Edbert J.; Nyby, Clara M.; Fan, Qingyuan; Shen, Xiaozhe; Reid, Alexander H.; Hoffmann, Matthias C.; Weathersby, Stephen; Wen, Jianguo; et al (March 2023, Nano Letters)

   Strong coupling between light and mechanical strain forms the foundation for next-generation optical micro- and nano-electromechanical systems. Such optomechanical responses in two-dimensional materials present novel types of functionalities arising from the weak van der Waals bond between atomic layers. Here, by using structure-sensitive megaelectronvolt ultrafast electron diffraction, we report the experimental observation of optically driven ultrafast in-plane strain in the layered group IV monochalcogenide germanium sulfide (GeS). Surprisingly, the photoinduced structural deformation exhibits strain amplitudes of order 0.1% with a 10 ps fast response time and a significant in-plane anisotropy between zigzag and armchair crystallographic directions. Rather than arising due to heating, experimental and theoretical investigations suggest deformation potentials caused by electronic density redistribution and converse piezoelectric effects generated by photoinduced electric fields are the dominant contributors to the observed dynamic anisotropic strains. Our observations define new avenues for ultrafast optomechanical control and strain engineering within functional devices. 

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