title: Observation of angle-modulated switch between enhancement and suppression of nonlinear optical processes.
abstract: We simultaneously investigate the four-wave mixing and the fluorescence signals via two cascade electromagnetically induced transparency (EIT) systems in atomic rubidium vapor. By manipulating the deflection angle between the probe beam and certain coupling beams, the dark state can extraordinarily switch to bright state, induced by the angle-modulation on the dressing effect. Besides, in the fluorescence signal, the peak of two-photon fluorescence due to classical emission and the dip of single-photon fluorescence due to dressing effect are distinguished, both in separate spectral curves and in the global profile of spectrum. Meanwhile, we observe and analyze the similarities and discrepancies between the two ground-state hyperfine levels F = 2 and F = 3 of Rb 85 for the first time.
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049, China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhengyang
authors.initials: Z
authors.lastname: Zhao
authors.forename: Peiying
authors.initials: P
authors.lastname: Li
authors.forename: Jiamin
authors.initials: J
authors.lastname: Yuan
authors.forename: Huayan
authors.initials: H
authors.lastname: Lan
authors.forename: Huaibin
authors.initials: H
authors.lastname: Zheng
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yanpeng
authors.initials: Y
authors.lastname: Zhang