The strong coupling between photons and bosonic excitations in matter produces hybrid quasiparticle states known as polaritons^1,2,3. Their signature is the avoided crossing between the eigenfrequencies of the coupled system illustrated by the Jaynes–Cummings Hamiltonian⁴. It has been observed in quantum electrodynamics experiments based on atoms^5,6, ions⁷, excitons^8,9,10, spin ensembles^11,12 and superconducting qubits¹³. In cavity optomechanics, polariton modes originate from the quantum-coherent coupling of a macroscopic mechanical vibration to the cavity radiation field^14,15. Here we investigate polaritonic modes in the motion of an optically levitated nanosphere^{16,17,18,19,20,21,22} in the quantum-coherent coupling regime. The particle is trapped in a high vacuum by an optical tweezer and strongly coupled to a single cavity mode by coherent scattering of the tweezer photons^{23,24,25,26,27}. The two-dimensional motion and optical cavity mode define an optomechanical system with three degrees of freedom. In the strong-coupling regime, we observe hybrid light–mechanical states with a vectorial nature. Our results pave the way towards protocols for quantum information transfer between photonic and phononic components and represent a step towards the demonstration of optomechanical entangled states at room temperature.

光子和物质中的玻色子激发之间的强耦合产生称为极化子^1,2,3的混合准粒子状态。它们的特征是避免了由 Jaynes-Cummings 哈密顿量⁴说明的耦合系统的特征频率之间的交叉。它已在基于原子^5,6、离子⁷、激子^8,9,10、自旋系综^11,12和超导量子比特¹³的量子电动力学实验中观察到。在腔光力学中，极化子模式源于宏观机械振动与腔辐射场的量子相干耦合^14,15. 在这里，我们研究了量子相干耦合机制中光学悬浮纳米球^{16、17、18、19、20、21、22运动中的极化子模式。}粒子被光学镊子捕获在高真空中，并通过镊子光子^{23、24、25、26、27}的相干散射强烈耦合到单腔模式。二维运动和光腔模式定义了一个具有三个自由度的光机械系统。在强耦合状态下，我们观察到具有矢量性质的混合光机械状态。我们的结果为光子和声子组件之间的量子信息传输协议铺平了道路，并代表了在室温下展示光机械纠缠态的一步。