A universal quantum frequency converter via four-wave-mixing processes

S. K. Singh, Mehmet Emre Taşgın

We show that, Four wave mixing (FWM) processes of grating can be controlled by the presence of interactions with a quantum dot or a molecule made by coupled quantum dots. By choosing the appropriate level spacing for the quantum emitter, one can either suppress or enhance the Four wave mixing process. We revel theoretically the underlying mechanism for this effect. (i) Suppression in FWM intensity occurs simply because induced Electromagnetic Induced Transparency does not allow the excitation at converted FWM frequency. (ii) Enhancement emerges since FWM process can be brought to resonance. Path interference effect cancels the nonresonant frequency terms. Furthermore, we have also shown that in case of coupled quantum dots enhancement increases significantly as compared to the case of a single quantum dot.

Yong Hui Yu

Kangkang Li, Renan Bu, Xiuxiu Wang +4 more

We study the realization of dual-bistability flip-flop converter in cavity and parametrically amplified four-wave mixing (FWM) process at a four-level cavity atomic system. Using the effect of nonreciprocity optical dual-bistability, we can obtain different output multi-mode states of probe transmission signal and FWM signal. We find the channel equalization ratio and optical contrast between multi-mode states is related to the degree of dual-bistability. Besides, the degree of dual-bistability can be controlled by the input parameters (frequency detuning and powers of the dressing beams). More, using electro-optical modulator and acoustic optical modulator to modulate the powers and frequency detuning, respectively, we can realize the fast conversion between different output states. And the switch speed of this flip-flop converter is about 16 ns. These outcomes may provide foundation for the development of all-optical devices and quantum information processing.

Sidarth Raghunathan

Rachel F. Offer, Dalius Stulga, Erling Riis +2 more

Atomic vapours are an experimentally simple and efficient system in which to study nonlinear wave mixing. We study a four-wave mixing (FWM) process in rubidium vapour which efficiently converts 780 and 776 nm light to 420 nm and 5.2 μm fields. In particular, we quantitatively investigate the transfer of orbital angular momentum (OAM) between the FWM fields. OAM, and structured light more generally, is an important research tool for optical manipulation, imaging and communication. Phase-matched nonlinear processes are both longitudinally and transversely phase coherent, and therefore OAM, which is associated with spiral phase fronts, must be conserved between the pump and generated fields. This makes wave mixing an ideal tool for frequency conversion and generation of a variety of OAM states for use in both classical and quantum communication.

Kevin Multani, Hubert S. Stokowski, Jeremy D. Witmer +8 more