Modulation of Light Waves by High Frequency Oscillations

A. I. Alekseev, Ashat M. Basharov

Peter D. D. Schwindt, Leo W. Hollberg, John E. Kitching

The detection of nonlinear magneto-optical rotation (NMOR) of polarized light through alkali atomic vapor is a highly sensitive technique for measuring magnetic fields. We demonstrate that when using frequency modulated light to excite the NMOR resonance, it is possible to cause the system to self-oscillate. The NMOR signal is not a simple replica of the sine wave modulation of the light, but rather contains many higher harmonics of the modulation frequency, and we implement two ways of processing the signal to recover the fundamental modulation frequency in the feedback loop and induce self-oscillation. Self-oscillation simplifies and reduces the power consumption of the electronics required to operate a magnetometer, making the NMOR technique attractive for commercialized magnetic sensors.

Nancy J. Halas

Marric Stephens

ptical parametric oscillators (OPOs) are indispensable in quantum optics, generating entangled photons for quantum communication and creating "squeezed" photon states for precision sensing (see Focus: Squeezing More from Gravitational-Wave Detectors).Now, researchers have demonstrated a device that does the same with phonons [1].As well as paving the way for producing entangled phonon pairs and squeezed phonon states, the new optomechanical parametric oscillator could be used for superresolution microscopy and for high-frequency modulation of light sources.

Christoph Georges, Jayson G. Cosme, Hans Keßler +2 more

Abstract We theoretically and experimentally explore the emergence of a dynamical density wave (DW) order in a driven dissipative atom–cavity system. A Bose–Einstein condensate is placed inside a high finesse optical resonator and pumped sideways by an optical standing wave. The pump strength is chosen to induce a stationary superradiant checkerboard DW order of the atoms stabilized by a strong intracavity light field. We show theoretically that, when the pump is modulated with sufficient strength at a frequency ω d close to a systemic resonance frequency ω >, a dynamical DW order emerges, which oscillates at the two frequencies ω > and ω < = ω d − ω >. This order is associated with a characteristic momentum spectrum, also found in experiments in addition to remnants of the oscillatory dynamics presumably damped by on-site interaction and heating, not included in the calculations. The oscillating density grating, associated with this order, suppresses pump-induced light scattering into the cavity. Similar mechanisms might be conceivable in light-driven electronic matter.

Misha Sumetsky