Efficient frequency conversion based on resonant four-wave mixing

Abstract

Efficient frequency conversion of photons has important applications in optical quantum technology because the frequency range suitable for photon manipulation and communication usually varies widely. Recently, an efficient frequency conversion system using a double- Λ four-wave mixing (FWM) process based on electromagnetically induced transparency (EIT) has attracted considerable attention because of its potential to achieve a nearly 100% conversion efficiency (CE). To obtain such a high CE, the spontaneous emission loss in this resonant-type FWM system must be suppressed considerably. A simple solution is to arrange the applied laser fields in a backward configuration. However, the phase mismatch due to this configuration can cause a significant decrease in CE. Here, we demonstrate that the phase mismatch can be effectively compensated by introducing the phase shift obtained by two-photon detuning. Under optimal conditions, we observe a wavelength conversion from 780 to 795 nm with a maximum CE of 91.2 % ± 0.6 % by using this backward FWM system at an optical depth of 130 in cold 87 Rb atoms. The current work represents an important step toward achieving low-loss, high-fidelity quantum frequency conversion based on EIT.

Effect of relaxation on the transfer of orbital angular momentum via four-wave mixing process in the four-level double lambda atomic system

“…A high conversion efficiency of 63% in the case of backward four wave mixing (BFWM) is obtained by Liu et al [32] in cold rubidium atomic medium with an optical depth of 48. Further improvement in conversion efficiency (91.2%)is obtained in BFWM configuration when optical depth is increased up to 130 in cold Rb-87 atomic medium [33].…”

“…Here, {|1⟩, |2⟩, |3⟩, |4⟩} are the old basis vector while {|1⟩, |2⟩, |T⟩, |D⟩} are the transformed basis. In equation (33), 4 by 4 unitary matrix can be used to translate operators from old to new basis. Transformed Hamiltonian (H trans )can be written as -…”

Controlling Frequency-Domain Hong-Ou-Mandel Interference via Electromagnetically Induced Transparency

“…(25) and ( 26)]. This system is also known as an open-loop FWM system and can be used as an efficient frequency converter [40][41][42][43][44].…”