In canonical optomechanical systems, mechanical vibrations are dynamically encoded on an optical probe field, which reciprocally exerts a backaction force. Because of the weak single-photon coupling strength achieved with macroscopic oscillators, most of the existing experiments were conducted with large photon numbers to achieve sizable effects, thereby hiding the original optomechanical nonlinearity. To increase the optomechanical interaction, we make use of subwavelength-sized ultrasensitive suspended nanowires inserted in the mode volume of a fiber-based microcavity. By scanning the nanowire within the cavity mode volume and measuring its impact on the cavity mode, we obtain a map of the 2D optomechanical interaction. Then, by using the toolbox of nanowire-based force-sensing protocols, we explore the backaction of the optomechanical interaction and map the optical force field experienced by the nanowire. These measurements also allow us to demonstrate the possibility to detect variations of the mean intracavity photon number smaller than unity. This implementation should also allow us to enter the promising regime of cavity optomechanics, where a single intracavity photon can displace the oscillator by more than its zero-point fluctuations, which will open novel perspectives in the field.

中文翻译：

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映射与亚波长大小的超灵敏纳米机械力传感器的腔光机相互作用。

在规范的光机械系统中，机械振动会在光学探针场上动态编码，从而相互施加反作用力。由于使用宏观振荡器获得的单光子耦合强度较弱，因此大多数现有实验都是使用大光子数进行的，以达到可观的效果，从而掩盖了原始的光机械非线性。为了增加光机械相互作用，我们利用亚波长尺寸的超灵敏悬浮纳米线插入基于纤维的微腔的模式体积中。通过在腔模体积内扫描纳米线并测量其对腔模的影响，我们获得了二维光机械相互作用的图。然后，通过使用基于纳米线的力感测协议的工具箱，我们探索了光机械相互作用的反作用，并绘制了纳米线所经历的光学力场。这些测量结果还使我们能够证明检测腔内平均光子数小于1的变化的可能性。这种实现方式还应该使我们能够进入有希望的腔光力学领域，其中单个腔内光子可以使振荡器移位超过零点波动，这将为该领域开辟新的前景。