Coherent and collimated blue light generated by four-wave mixing in Rb vapour

Abstract

We investigate frequency up-conversion of low power cw resonant radiation in Rb vapour as a function of various experimental parameters. We present evidence that the process of four wave mixing is responsible for unidirectional blue light generation and that the phase matching conditions along a light-induced waveguide determine the direction and divergence of the blue light. Velocity-selective excitation to the 5D level via step-wise and two-photon processes results in a Doppler-free dependence on the frequency detuning of the applied laser fields from the respective dipole-allowed transitions. Possible schemes for ultraviolet generation are discussed.

Propagation dynamics of controlled cross-talk via interplay betweenχ(1)andχ(3Hsu1, Welch2, Gord3 et al. 2011Phys. Rev. A140100View full textAdd to dashboardCite

“…by dropping the two-level absorption term from Eq. (12), such that only the ladder-transparency term…”

“…With an additional control field coupling to a fourth atomic level, the χ (3) process can significantly affect the dispersion [6] and absorption [7,8] properties of the probe field. The efficient parametric generation of a four wave-mixing (FWM) field using the resonant χ (3) process in a four-level double-ladder atomic system has been recently demonstrated [6,[8][9][10][11][12][13][14]. In particular, this system allows efficient frequency up-conversion [10][11][12] and down-conversion [13,14] through the use of low-power continuous-wave lasers that can be used for ultraviolet generation and quantum communication [11][12][13][14].…”

“…The efficient parametric generation of a four wave-mixing (FWM) field using the resonant χ (3) process in a four-level double-ladder atomic system has been recently demonstrated [6,[8][9][10][11][12][13][14]. In particular, this system allows efficient frequency up-conversion [10][11][12] and down-conversion [13,14] through the use of low-power continuous-wave lasers that can be used for ultraviolet generation and quantum communication [11][12][13][14]. Previous experimental and theoretical studies of the double-ladder system have also revealed many remarkable properties that are sensitive to the phase and amplitude of the control laser and can be used for polarization control and laser-frequency stabilization [15][16][17][18][19][20][21][22][23].…”

Anomalous two-photon spectral features in warm rubidium vapor

“…For example, complex light-atom interaction has been induced in three-level atomic media using electromagnetically induced transparency [2,3], electromagnetically induced absorption [3,4], coherent trapping of atomic populations [5], and quantum interference between atomic energy levels [6]. These coherent processes have been the basis for highly sensitive magnetometers [7,8], quantum information processing using Kerr-type nonlinearities [9], efficient photon-counting [10,11], frequency up-conversion using atomic vapors [12,13], lasing without population inversion [6], and highly compact frequency standards [14,15].…”

Linewidth of collimated wavelength-converted emission in Rb vapour

“…Since then it has become an active area of research of several groups [3,4,5,6,7] and has been even suggested for advanced undergraduate laboratories [8]. The technique is of interest because new optical field generation in atomic media can lead to important applications in quantuminformation science [9] and low atom number detection [10].…”