论文标题
在自由空间中悬浮的纳米颗粒对光挤压光
Ponderomotive squeezing of light by a levitated nanoparticle in free space
论文作者
论文摘要
通过与光的相互作用，可以将机械兼容的元素设置为运动。反过来，这种轻度驱动的运动会引起电磁场中的浮力相关性。在光学机械系统中，通常使用空腔来增强这些相关性，直到它们产生光量子的量子。在自由空间的场景中，没有使用空腔，对挤压的观察仍然可能，但由于相互作用的疲软而具有挑战性，到目前为止尚未报道。在这里，我们测量了在自由空间光学镊子中悬浮的纳米粒子散射的光线状态。我们观察到将光波动的减少低于$ 25 $〜\％，低于真空水平，带宽约为$ 15 $ 〜khz。我们的结果很好地解释了纳米颗粒与电磁连续体之间的线性化偶极相互作用。这些蓬勃发展的相关性为使用悬浮系统（例如低于标准量子限制的力测量）打开了量子增强感测和计量的大门。
A mechanically compliant element can be set into motion by the interaction with light. In turn, this light-driven motion can give rise to ponderomotive correlations in the electromagnetic field. In optomechanical systems, cavities are often employed to enhance these correlations up to the point where they generate quantum squeezing of light. In free-space scenarios, where no cavity is used, observation of squeezing remains possible but challenging due to the weakness of the interaction, and has not been reported so far. Here, we measure the ponderomotively squeezed state of light scattered by a nanoparticle levitated in a free-space optical tweezer. We observe a reduction of the optical fluctuations by up to $25$~\% below the vacuum level, in a bandwidth of about $15$~kHz. Our results are well explained by a linearized dipole interaction between the nanoparticle and the electromagnetic continuum. These ponderomotive correlations open the door to quantum-enhanced sensing and metrology with levitated systems, such as force measurements below the standard quantum limit.
