论文标题
连贯的散射2D冷却在悬浮的腔体光学机电中
Coherent scattering 2D cooling in levitated cavity optomechanics
论文作者
论文摘要
相干散射（CS）设置提供的强烈光机电耦合允许实验实现量子基态空腔冷却悬浮的纳米颗粒的轴向运动[U. Delić等人，Science 367，892（2020）]。现在，一个有吸引力的里程碑是在横向平面的任何方向上的整个面内运动的量子2D冷却。 By a simple adjustment of the trap polarisation, one obtains two nearly equivalent modes, with similar frequencies $ω_{x}\simω_{y}$ and optomechanical couplings $g_{x}\simeq g_{y}$ -- in this experimental configuration we identify an optimal trap ellipticity, nanosphere size and cavity linewidth which allows for efficient 2D冷却。此外，我们发现2D冷却到占用$ n_ {x}+n_ {y} \ lysesim1 $在中度真空（$ 10^{ - 6} $ mbar）在“ goldilocks”区域中是有可能的g_ {x}，g_ {y} \ lyseSim |ω___________________________________________________\simmκ$，在这种情况下，人们平衡了抑制深色模式的需求，而避免了模式或较低的cooperativitivitivitivition或$κ$（$κ$（$γ$）是Cavity decay deatay rate rate rate for（Moctional Heation for）。有了强耦合方案$ g_ {x}，g_ {y} \gtrsimκ$从$ x $，$ y $和空腔灯模式之间的真正三向混合构图，从而导致杂交明亮/黑暗模式。最后，我们表明，悬浮的设置中的明亮/深色模式具有简单的几何解释，该解释通过横向平面的旋转与方向传感有关。
The strong light-matter optomechanical coupling offered by Coherent Scattering (CS) set-ups have allowed the experimental realisation of quantum ground state cavity cooling of the axial motion of a levitated nanoparticle [U. Delić et al., Science 367, 892 (2020)]. An appealing milestone is now quantum 2D cooling of the full in-plane motion, in any direction in the transverse plane. By a simple adjustment of the trap polarisation, one obtains two nearly equivalent modes, with similar frequencies $ω_{x}\simω_{y}$ and optomechanical couplings $g_{x}\simeq g_{y}$ -- in this experimental configuration we identify an optimal trap ellipticity, nanosphere size and cavity linewidth which allows for efficient 2D cooling. Moreover, we find that 2D cooling to occupancies $n_{x}+n_{y}\lesssim1$ at moderate vacuum ($10^{-6}$ mbar) is possible in a "Goldilocks" zone bounded by $\sqrt{κΓ/4}\lesssim g_{x},g_{y}\lesssim|ω_{x}-ω_{y}|\lesssimκ$, where one balances the need to suppress dark modes whilst avoiding far-detuning of either mode or low cooperativities, and $κ$ ($Γ$) is the cavity decay rate (motional heating rate). With strong-coupling regimes $g_{x},g_{y}\gtrsimκ$ in view one must consider the genuine three-way hybridisation between $x$, $y$ and the cavity light mode resulting in hybridized bright/dark modes. Finally, we show that bright/dark modes in the levitated set-up have a simple geometrical interpretation, related by rotations in the transverse plane, with implications for directional sensing.
