Color-switching in an optical parametric oscillator using a phase-conjugate mirror.

We construct a phase-conjugate resonator which passively produces stable pulses that alternate between the probe and the conjugate colors. The requisite phase-conjugate mirror inside the resonator is constructed using non-degenerate four-wave mixing (4WM) in rubidium vapor. The glancing-angle phase-conjugate mirror is a 100% output coupler, and therefore this resonator is unusual in that no light circulates the cavity more than once.

Pseudo-arbitrary sideband generation by phase modulation calculated with iterative phase retrieval.

A method for arbitrarily tailoring amplitude and phase of sidebands generated with a phase shifting electro-optic modulator (EOM) is presented. The technique is extremely simple experimentally, requiring only a single EOM driven by an arbitrary waveform generator. The required time domain phase modulation is calculated using an iterative phase retrieval algorithm, which takes into account the desired spectrum (both amplitude and phase), and other physical constraints.

Two-beam coupling in the production of quantum correlated images by four-wave mixing.

We investigate the effect of 2-beam coupling in different imaging geometries in generating intensity-difference squeezing from four-wave mixing (4WM) in Rb atomic vapors. A recently-introduced dual-seeding technique can cancel out the classical noise in a seeded four-wave mixing process. This dual-seeding technique, however, can introduce new complications that involve 2-beam coupling between different seeded spatial modes in the atomic vapor and can ruin squeezing at frequencies on the order of the atomic linewidth and below.

Effect of imperfect homodyne visibility on multi-spatial-mode two-mode squeezing measurements.

We study the effect of homodyne detector visibility on the measurement of quadrature squeezing for a spatially multi-mode source of two-mode squeezed light. Sources like optical parametric oscillators (OPO) typically produce squeezing in a single spatial mode because the nonlinear medium is within a mode-selective optical cavity. For such a source, imperfect interference visibility in the homodyne detector couples in additional vacuum noise, which can be accounted for by introducing an equivalent loss term.

Twin-beam intensity-difference squeezing below 10 Hz.

We report the generation of strong, bright-beam intensity-difference squeezing down to measurement frequencies below 10 Hz. We generate two-mode squeezing in a four-wave mixing (4WM) process in Rb vapor, where the single-pass-gain nonlinear process does not require cavity locking and only relies on passive stability. We use diode laser technology and several techniques, including dual seeding, to remove the noise introduced by seeding the 4WM process as well as the background noise.