M. Y. Lanzerotti

HIGH-REFLECTIVITY, WIDE-BANDWIDTH OPTICAL PHASE CONJUGATION VIA FOUR-WAVE MIXING IN POTASSIUM VAPOR

We report on a high‐reflectivity (up to 670%) wide‐bandwidth (up to 230 MHz) phase‐conjugate mirror formed using backward‐four‐wave mixing with continuous‐wave pump beams in a 2‐mm potassium vapor cell. The reflectivities and bandwidths are significantly larger than have been measured previously, and the bandwidth is ten times greater than is predicted theoretically. The reflectivity‐bandwidth product is more than an order of magnitude improvement over those previously achieved with other continuous‐wave phase‐conjugate systems.

Quantum Noise in Optical Phase Conjugation Performed in an Atomic Vapor

Many researchers have studied the noise properties of optical amplifiers and have shown that all nonlinear optical amplifiers introduce noise into the amplified beam.1 In our research, we have conducted a theoretical and experimental investigation of the quantum noise generated by a phase-conjugate mirror (PCM) obtained using four-wave mixing in potassium vapor. An ideal PCM will generate light that exhibits excess quantum noise that is inherent to the phase conjugation process.2 Additional noise can be introduced as a result of fluctuations (e.g., collisions) in the nonlinear medium, as has been predicted for the nonlinear process of two-beam coupling in an atomic vapor.3 These sources of noise determine the fundamental limit on the smallest signal that can be phase-conjugated.

Spectral Modification of Ultrashort Pulses Propagating through an Atomic Vapor

Extensive research has been performed on the temporal behavior of resonant short pulses propagating through an atomic vapor.1 In our studies, we have investigated experimentally and theoretically the modification of the spectrum of pulses propagating through an atomic vapor under conditions in which the pulse duration is much shorter than any of the relaxation times of the atomic system. We observe novel features in the spectrum of the transmitted pulse under conditions in which the area of the incident pulse is of the order of unity or greater.