An optically dense, anisotropic cloud of ultracold atoms is used to observe recoil-induced resonances in the high-gain regime. Optical gains as large as 30 are realized, limited primarily by pump depletion. We demonstrate a light-amplified all-optical switch based on this effect. The switch exhibits contrasts exceeding 35 dB.
We have investigated recoil-induced resonances in laser-cooled atoms for the purpose of developing an optical switch. In contrast to our earlier experiments Citation8, we employ a system in which the trapping beams are left on during the course of the measurement. We not only find the expected narrow resonance but also a much wider resonance. The widths of the wide and narrow resonances differ by three orders of magnitude. In addition, the two resonances show different temporal dynamics. We explore the utility of each resonance as an optical switch.
We use an optically dense anisotropic magneto-optical trap to study recoil-induced resonances (RIRs) in the transient high-gain regime. We find that two distinct mechanisms govern the atomic dynamics: the finite, frequency-dependent atomic response time and momentum-space population redistribution. At low input probe intensities, the residual Doppler width of the atoms, combined with the finite atomic response time, result in a linear transient hysteretic effect that modifies the locations, widths, and magnitudes of the resulting gain spectra depending on the sign of the scan chirp. When larger intensities (i.e., greater than a few $\ensuremath{\mu}\text{W}/{\text{cm}}^{2}$) are incident on the atomic sample for several $\ensuremath{\mu}\text{s}$, hole burning in the atomic sample momentum distribution leads to a coherent population redistribution that persists for approximately $100\text{ }\ensuremath{\mu}\text{s}$. We propose using RIRs to engineer the atomic momentum distribution to enhance the nonlinear atom-photon coupling. We present a numerical model and compare the calculated and experimental results to verify our interpretation.
A Bose-Einstein condensate illuminated by a single off-resonant laser beam ("dressed condensate") shows a high gain for matter waves and light. We have characterized the optical and atom-optical properties of the dressed condensate by injecting light or atoms, illuminating the key role of long-lived matter wave gratings produced by the condensate at rest and recoiling atoms. The narrow bandwidth for optical gain gave rise to an extremely slow group velocity of an amplified light pulse ( approximately 1 m/s).
We report the confinement of large clouds of ultracold 85Rb atoms in a standing-wave dipole trap formed by the two counterpropagating modes of a high-Q ring cavity. Studying the properties of this trap, we demonstrate loading of higher-order transverse cavity modes and excite recoil-induced resonances.