V Cavity Quantum Optics and the Quantum Measurement Process

Arka Majumdar, Alexander T. Papageorge, Erik D. Kim +4 more

In recent experiments on coupled quantum dot (QD) optical cavity systems, a pronounced interaction between the dot and the cavity has been observed even for detunings of many cavity linewidths. This interaction has been attributed to an incoherent phonon-mediated scattering process and is absent in atomic systems. Here, we demonstrate that despite its incoherent nature, this process preserves the signatures of coherent interaction between a QD and a strong driving laser, which may be observed via the optical emission from the off-resonant cavity. Under bichromatic driving of the QD, the cavity emission exhibits spectral features consistent with optical dressing of the QD transition. These cavity emission measurements are more akin to absorption measurements of a strongly driven QD rather than resonance fluorescence measurements. In addition to revealing new aspects of the off-resonant QD-cavity interaction, this result provides a new, simpler means of coherently probing QDs and opens the possibility of employing off-resonant cavities to optically interface QD nodes in quantum networks.

Harry J. Kimble, O. Carnal, Zhongliang Hu +4 more

P. M. Alsing, Gerard J Milburn, Daniel F. Walls

We analyze schemes for performing quantum nondemolition (QND) measurements in optical cavities. We consider three schemes: (1) measurement of a quadrature phase amplitude using a parametric process, (2) measurement of a quadrature phase amplitude using the optical Kerr effect in a nonlinear fiber, and (3) measurement of the photon number also using the Kerr effect in a fiber. We show that in the second scheme an enhancement of the QND effect may be obtained by making the cavity finesse for the signal larger than that for the probe.

Paolo Tombesi, Daniel F. Walls

Haoran Lv, Bozheng Xing, Xiujie Fang +6 more

In the process of generating squeezed light based on parameter down-conversion, the optical cavity loss affects the performance of the squeezed light. In this article, we propose a new method for measuring cavity loss in locking conditions, which has the advantage of being able to accurately measure cavity loss under optical cavity operating conditions. Based on this measurement method, we study the influence of cavity loss on SHG and OPO processes. The experiment results indicate that the reducing the additional cavity loss, such as cavity loss caused by thermal noise can effectively improve the performance of SHG and OPO cavities, and enhance the squeezing degree of squeezed light sources, which will restrict the further improvement of the squeezed light. The research results of this article are of great significance for the generation of high-performance squeezed light and quantum precision sensing based on quantum enhancement.

Stig Stenholm