Nonlinear Effects in Pulse Propagation through Doppler-Broadened Closed-Loop Atomic Media

Abstract

Nonlinear effects in pulse propagation through a medium consisting of four-level double-$\Lambda$-type systems are studied theoretically. We apply three continous-wave driving fields and a pulsed probe field such that they form a closed interaction loop. Due to the closed loop and the finite frequency width of the probe pulses the multiphoton resonance condition cannot be fulfilled, such that a time-dependent analysis is required. By identifying the different underlying physical processes we determine the parts of the solution relevant to calculate the linear and nonlinear response of the system. We find that the system can exhibit a strong intensity dependent refractive index with small absorption over a range of several natural linewidths. For a realistic example we include Doppler and pressure broadening and calculate the nonlinear selfphase modulation in a gas cell with Sodium vapor and Argon buffer gas. We find that a selfphase modulation of $\pi$ is achieved after a propagation of few centimeters through the medium while the absorption in the corresponding spectral range is small.

4 figures

References in corpus (5)

• Enhancement of Kerr nonlinearity via multi-photon coherence
• Phase-dependent interaction in a 4-level atomic configuration
• Light propagation through closed-loop atomic media beyond the multiphoton resonance condition
• Phase-dependent light propagation in atomic vapors
• Phase correlation of laser waves with arbitrary frequency spacing

Cited by in corpus (4)

• Electromagnetically induced transparency and nonlinear pulse propagation in a combined tripod and $\Lambda$ atom-light coupling scheme
• Pulse-splitting in light propagation through $N$-type atomic media due to an interplay of Kerr-nonlinearity and group velocity dispersion
• Sub-wavelength position measurements with running wave driving fields
• Cavity-induced giant Kerr nonlinearities in a driven V-type atom