Highly efficient four-wave mixing induced by quantum constructive interference in rubidium vapour

We demonstrate efficient four-wave mixing with an intensity conversion efficiency of nearly 100% in theory without considering the Doppler-broadening effect in a four-level double-Λ system of hot 87 Rb gas.The corresponding experimental value of about 73% was reported in our earlier work under the same conditions.This dramatic efficiency is critically dependent on the constructive interference between two four-wave mixing processes relevant to the internally generated four-wave mixing signal.     

Highly efficient four-wave mixing induced by quantum constructive interference in rubidium vapour

We demonstrate efficient four-wave mixing with an intensity conversion efficiency of nearly 100% in theory without considering the Doppler-broadening effect in a four-level double-Λ system of hot ⁸⁷Rb gas. The corresponding experimental value of about 73% was reported in our earlier work under the same conditions. This dramatic efficiency is critically dependent on the constructive interference between two four-wave mixing processes relevant to the internally generated four-wave mixing signal.     

Pump-depleting four-wave mixing in supercontinuum-generating microstructure fibers

Four-wave mixing processes are shown to provide a high efficiency of non-linear optical frequency conversion and spectral transformation of ultrashort pulses in supercontinuum-generating microstructure fibers. Pump-depleting conversion of 800-nm radiation to the spectral range around 500 nm is achieved by phase-matching the parametric four-wave mixing process for 80-fs Ti:sapphire-laser pulses. The ways to use microstructure fibers for generating frequency-tunable radiation through four-wave mixing with the maximum efficiency of pump-field frequency conversion are discussed. PACS 42.65.Wi; 42.81.Qb     

色散位移光纤中零色散波长纵向分布对四波混频转换效率的影响

研究了色散位移光纤零色散区域附近的四波混频特性 ,讨论了当零色散波长彼此不同的多段光纤连接起来后对四波混频效率的影响。理论计算结果表明 ,在信号光和抽运光波长间隔较小的区域 ,各光纤对四波混频过程都有贡献 ,且互相调制 ,并出现增益现象 ,有着很复杂的效率图。     

电磁诱导透明窗口中温度、功率及偏振特性对四波混频信号的影响

电磁诱导透明(EIT)效应改变了介质的吸收特性,导致了线性极化率的抑制和非线性极化率的提高,从而可以实现高效率四波混频的产生.实现了基于EIT的高效四波混频,且研究了样品温度、入射光功率和入射光偏振状态对四波混频信号的影响特性.研究发现,温度对样品铷的两个同位素87Rb和85Rb的影响有所差别,它们分别存在一个最佳工作...     

有机染料溶液中简并的四波混频和位相复共轭研究

本文研究了近共振增强的四能级系统有机染料溶液中简并的四波混频后向波和前向波的位相复共轭特性。用有效长度为5毫米、浓度为2.5×10^-5克分子的叶绿素A甲醇溶液作介质,当调QNd:YAG倍频抽运光能量为8毫焦耳时,非线性反射率为22％。研究了若丹明6G酒精溶液双光子共振增强的简并的四波混频作用。测量了非线性反射率与介质浓度及抽运波和物波强度的关系曲线。理论分析了四波混频前向波的位相复共轭特性,实验证实了理论的预言。另外,把四重简并的四波混频推广到二重简并。用9740有机染料二氯乙烷饱和吸收溶液作介质,实现了1.06微米到5320埃的象转换。介质长度为5毫米,抽运光能量为5毫焦耳时,转换效率达25％。理论分析表明,用对红外近共振吸收而对可见辐射是透明的介质可实现高效率红外象转换。 关键词：     

Quantum entanglement of Fock states with perfectly efficient ultraslow single-probe photon four-wave mixing

We propose a method to achieve quantum entanglement of two Fock states with perfectly efficient, ultraslow propagation enhanced four-wave mixing. A cold atomic medium is illuminated with a two-mode cw control laser to produce coherent mixtures of excited states. An ultraslowly propagating, single-photon quantum probe field completes the four-wave mixing with 100% photon flux conversion efficiency, creating a depth dependent entanglement of two Fock states. We show that at a suitable propagation distance, a maximum entangled state is created with a single-photon wave-packet state that has 50% probability of being in each of two product-type Fock states.     

基于光子晶体光纤四波混频效应的波长转换研究

研究了光子晶体光纤中的四波混频效应及其波长转换.采用长度为25 m的高非线性色散平坦光子晶体光纤,当泵浦功率为19.8 dBm时,得到100 nm的转换带宽和－20 dB的最大转换效率.实验结果表明,当信号功率低于四波混频阈值时,两路不同波长的信号同时输入产生的四波混频效应互不影响.     

Characterize and optimize the four-wave mixing in dual-interferometer coupled silicon microrings

By designing and fabricating a series of dual-interferometer coupled silicon microrings, the coupling condition of the pump, signal, and idler beams can be engineered independently and then we carried out both the continuous-wave and pulse pumped four-wave mixing experiments to verify the dependence of conversion efficiency on the coupling conditions of the four interacting beams, respectively. Under the continuous-wave pump, the four-wave mixing efficiency gets maximized when both the pump and signal/idler beams are closely operated at the critical coupling point, while for the pulse pump case, the efficiency can be enhanced greatly when the pump and converted idler beams are all overcoupled. These experiment results agree well with our theoretical calculations. Our design provides a platform for explicitly characterizing the four-wave mixing under different pumping conditions, and offers a method to optimize the four-wave mixing, which will facilitate the development of on-chip all-optical signal processing with a higher efficiency or reduced pump power.     

SRS generation under phase matching conditions for four-wave interactions of SRS components in birefringent Raman-active crystals

The possibilities of efficient four-wave SRS generation in the schemes of cavity and cavity-amplifier SRS converters with the implementation of phase matching conditions for four-wave mixing of different SRS radiation components at an appropriate orientation of birefringent SRS crystals have been considered based on a numerical simulation. The threshold characteristics and achievable energetic parameters of the SRS generation of different frequency radiation components have been analyzed under the conditions of implementation of phase matching for four-wave mixing. Conditions have been found for a low-threshold SRS-four-wave mixing generation of an anti-Stokes wave with a conversion efficiency of up to 40%, as well as of the first, second, and third Stokes SRS components with conversion efficiencies of up to 90, 80, and 30%, respectively.