We demonstrate that fast tunable optical switches and tunable slow-light devices can be designed as optical cavities entangled with quantum dots. We derive the analytical conditions for switching and tuning the filter transmittance, considering both dipole-induced transparency and electromagnetic-induced transparency effects.
We analyze the behavior of a quantum dot embedded in an add-drop filter for optical signal processing applications. The joint effects of dipole induced transparency and electromagnetic induced transparency, which shift the transparency peak induced by a dipole in an add-drop filter due to vacuum Rabi splitting, have been considered. The mathematical model and some different conditions for tuning the transparency peak are derived for application to all optical switching and wavelength tunable devices.
Tunable on-chip optical delay has long been a key target for the research community, as it is the enabling technology behind delay lines, signal retiming and other applications vital to optical signal processing. To date, the field has been limited by high optical losses associated with slow light or delay structures. Here, we present a novel tunable delay line, based on a coupled cavity system exhibiting an electromagnetically induced transparency-like transmission spectrum, with record low loss, around 15 dB/ns. By tuning a single cavity, the delay of the complete structure can be tuned over 120 ps, with the maximum delay approaching 300 ps.
We analyze the behaviour of a quantum dot embedded in a photonic crystal add-drop filter and in a direct coupled photonic crystal microcavity for optical signal processing applications. The joint effect of dipole induced transparency and electromagnetic induced transparency, considering a cascade configuration of the quantum dot, are used to modify the behaviour of the whole system. The mathematical model and a number of different conditions for tuning the frequency response of the filters are derived for application in all-optical switching and wavelength tunable devices.
The system optical response in quantum dot molecule (QDM)-embedded coupled cavities with photothermal effect is investigated theoretically. Couple resonator-induced transparency can be found first when only considering the photon tunneling between the double cavities. After implanting QDMs with tunneling effects into the right cavity, three transparency windows are observed due to QDMs and tunneling-induced transparency (TIT) therein. The fourth transparency window is formed due to photothermally induced transparency (PTIT). The results indicate the system absorption can be tuned by changing the system coupling strengths and frequency detunings. Furthermore, the transmission and group delay of the probe field are examined. Especially, the group delay in different transparency windows can be adjusted by the tunneling effect in the QDMs, and the group delay in PTIT can also be controlled by the system coupling strengths, etc. The research provides a new way of using the TIT to control the PTIT, which may be applied to design novel nanophotonic devices.
In this paper, through an input-output formulation based on a full-quantum mechanical treatment of light matter interaction, some regimes to detect dipole induced transparency and electromagnetic induced transparency have been given. The main novelty of this paper is that the possibility to achieve total reflectivity from a system composed of many cavities could be obtained increasing the number of cavities, relaxing at the same time the condition for coupling a quantum state and a cavity mode. The main applications of this study are related to switching and all optical buffers, mainly in the field of quantum information processing.