AlGaAs/InAlGaAs多量子阱光子晶体波导的超快反射率调制

用于MHz范围内高反射率高Q值微机械谐振器的单晶AlGaAs异质结构

Monocrystalline AlGaAs heterostructures for high-reflectivity high-Q micromechanical resonators in the MHz regime

我们提出了高性能兆赫微机械振荡器的基础上独立外延AlGaAs分布布拉格反射器。与电介质反射器相比，单晶异质结构的低机械损耗引起可实现的机械品质因数Q的显著改善，同时表现出接近1的反射率。实验结果表明，在4K下，薄膜的光学反射率超过99.98%，机械品质因数达到20000.这种材料系统不仅是具有超低热噪声的光学薄膜的有趣候选者，而且还为大规模微机械镜的量子光学控制提供了一条有前途的道路。

Intersubband polariton-polariton scattering in a dispersive microcavity

The ultrafast scattering dynamics of intersubband polaritons in dispersive cavities embedding GaAs/AlGaAs quantum wells are studied directly within their band structure using a non-collinear pump-probe geometry with phase-stable mid-infrared pulses. Selective excitation of the lower polariton at a frequency of ~25 THz and at a finite in-plane momentum, $k_{||}$, leads to the emergence of a narrowband maximum in the probe reflectivity at $k_{||}=0$. A quantum mechanical model identifies the underlying microscopic process as stimulated coherent polariton-polariton scattering. These results mark …