Acoustic or mechanical resonators have emerged as a promising means to mediate efficient microwave-to-optical conversion. Here, we demonstrate conversion of microwaves up to 4.5 GHz in frequency to 1500 nm wavelength light using optomechanical interactions on suspended thin-film lithium niobate. Our method uses an interdigital transducer that drives a freestanding 100 μm-long thin-film acoustic resonator to modulate light traveling in a Mach–Zehnder interferometer or racetrack cavity. The strong microwave-to-acoustic coupling offered by the transducer in conjunction with the strong photoelastic, piezoelectric, and electro-optic effects of lithium niobate allows us to achieve a half-wave voltage of $V_{\pi }=4.6\mathrm{V}$ and $V_{\pi }=0.77\mathrm{V}$ for the Mach–Zehnder interferometer and racetrack resonator, respectively. The acousto-optic racetrack cavity exhibits an optomechanical single-photon coupling strength of 1.1 kHz. To highlight the versatility of our system, we also demonstrate a microwave photonic link with unitary gain, which refers to a 0 dB microwave power transmission over an optical channel. Our integrated nanophotonic platform, which leverages the compelling properties of lithium niobate, could help enable efficient conversion between microwave and optical fields.

中文翻译：

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使用铌酸锂薄膜声谐振器的微波到光的转换

声学或机械谐振器已经成为介导有效的微波到光学转换的一种有前途的手段。在这里，我们展示了使用悬浮式薄膜铌酸锂上的光机械相互作用将频率高达4.5 GHz的微波转换为1500 nm波长的光。我们的方法使用一个叉指式换能器，该换能器驱动一个独立的100μm长的薄膜声谐振器，以调制在Mach-Zehnder干涉仪或跑道空腔中传播的光。传感器提供的强大的微波声耦合以及铌酸锂的强大的光弹性，压电和电光效应，使我们能够获得${\mathrm{伏特}}_{\pi }=4.6\mathrm{伏特}$ 和 ${\mathrm{伏特}}_{\pi }=0.77\mathrm{伏特}$分别用于马赫曾德尔干涉仪和跑道谐振器。声光跑道腔具有1.1 kHz的光机械单光子耦合强度。为了突出我们系统的多功能性，我们还演示了具有单位增益的微波光子链路，这是指在光信道上传输0 dB的微波功率。我们集成的纳米光子平台，利用铌酸锂的引人注目的特性，可以帮助实现微波和光场之间的有效转换。