A four-level quantum dot (QD) nanostructure interacting with four fields (two weak near-infrared (NIR) pulses and two control fields) forms the well-known double-cascade configuration. We investigate the cross-phase modulation (XPM) between the two NIR pulses. The results show, in such a closed-loop scheme, that the XPM can be greatly enhanced, while the linear absorption and two-photon absorption (gain) can be efficiently depressed by tuning the relative phase among the applied fields. This protocol may have potential applications in NIR all-optical switch design and quantum information processing with the solid-state materials.
With the presence of the signal pulse, a quantum dot (QD) four-level structure interacting with four fields forms a double-cascade configuration. The linear optical properties for amplification, absorption, and dispersion of two weak near-infrared (NIR) lights in this scheme are investigated. It shows that the amplification, transparency, normal and anomalous dispersion of the probe and signal fields, i.e., the two NIR waves, can be achieved by adjusting the relative phase of the applied lasers, the probe detuning, and the two pump Rabi energies appropriately, while when the signal pulse is removed, the nonlinear optical phenomenon four-wave mixing (FWM) originating from quantum interference is demonstrated. A highly efficient FWM process with a NIR mixing field generated can be realized in this system. Such investigation in a semiconductor QD system with flexible design and widely adjustable parameters may provide new possibilities for realizing the efficient generation and gain of NIR waves and manipulating light propagation between subluminal and superluminal in the solid-state materials.
We use the Green's tensor quantization theory for open resonant nanostructures with absorption losses to study cross-phase modulation (XPM) at the single-photon level in nanoscale Kerr-type epsilon-near-zero (ENZ) materials with an effective nonlinear susceptibility integrated inside dual-wavelength nanocavities. We obtain analytical formulas for the XPM frequency shifts in hybrid nanocavities that simultaneously trap a classical probe beam at 1.5
μm and single-photon pump at 3
μm wavelengths. We present a comprehensive analysis of the fundamental limits for mid-infrared single-photon detection in the quantum nondemolition modality for nanostructured cadmium oxide (CdO) regions with ENZ-enhanced nonlinearity embedded in a silicon (Si) environment inversely designed by free-form topology optimization. We numerically implement our theoretical results using finite element simulations within the rigorous framework of quasi-normal modes, demonstrating a single-photon XPM frequency shift
Δfs≈55.6 GHz with fractional shift (i.e., frequency pulling)
Δfs/fs≈2.78×10−4 and addressing the feasibility of detection in the hybrid Si-CdO dual-wavelength nanocavity, either with a classical probe beam or a squeezed probe state, including the contributions of traditional limitations from self-phase modulation noise, thermorefractive noise, shot noise, and free-carrier absorption effects. Finally, we present a comparative size scaling analysis of the XPM phase shift and phase noise contributions for dual-wavelength nanocavities based on CdO and indium tin oxide (ITO) nonlinear ENZ materials. This work establishes a robust benchmark for the engineering of mid-infrared single-photon nonlinear devices such as nondemolition quantum detectors, sensors, and all-optical gates on a solid state photonic platform.