ABSTRACT
We demonstrate an ultra-low light level optical modulator using a tapered nano fiber embedded in a hot rubidium vapor. The control and signal beams are co-propagating but orthogonally polarized, leading to a degenerate V-system involving coherent superpositions of Zeeman sublevels. The modulation is due primarily to the quantum Zeno effect for the signal beam induced by the control beam. For a control power of 40 nW and a signal power of 100 pW, we observe near 100% modulation. The ultra-low power level needed for the modulation is due to a combination of the Zeno effect and the extreme field localization in the evanescent field around the taper.
ABSTRACT
The most successful Ring Laser Gyroscopes (RLGs) are gas-laser based. It has been recently shown that the type of anomalous dispersion associated with fast light, when present inside an RLG, can increase its scale factor. We evaluate several proposed methods for realizing this appropriate dispersion in gas media, theoretically and experimentally. We find linear gas media in general to be unsuitable for this purpose, with mixed prospects for nonlinear effects.
Subject(s)
Acceleration , Computer-Aided Design , Gases/chemistry , Lasers , Models, Theoretical , Transducers , Computer Simulation , Equipment Design , Equipment Failure Analysis , Light , Scattering, RadiationABSTRACT
The group velocity of light becomes superluminal in a medium with a tuned negative dispersion, using two gain peaks, for example. Inside a laser, however, the gain is constant, equaling the loss. We show here that the effective dispersion experienced by the lasing frequency is still sensitive to the spectral profile of the unsaturated gain. In particular, a dip in the gain profile leads to a superluminal group velocity for the lasing mode. The displacement sensitivity of the lasing frequency is enhanced by nearly five orders of magnitude, leading to a versatile sensor of hyper sensitivity.
Subject(s)
Lasers , Light , Optics and Photonics/instrumentation , Optics and Photonics/methods , Equipment Design , Gravitation , Luminescence , Models, Theoretical , RotationABSTRACT
We demonstrate experimentally slow and fast light effects achieved simultaneously using Raman gain and pump depletion in an atomic vapor. Heterodyne phase measurements show opposite dispersion characteristics at the pump and probe frequencies. Optical pulse propagations in the vapor medium confirm the slow and fast light effects due to these dispersions. We discuss applications of this technique in recently proposed rotation sensing and broadband detection schemes.
Subject(s)
Spectrum Analysis, Raman/methods , Light , Scattering, RadiationABSTRACT
We report the observation of low-light level optical interactions in a tapered optical nanofiber (TNF) embedded in a hot rubidium vapor. The small optical mode area plays a significant role in the optical properties of the hot vapor Rb-TNF system, allowing nonlinear optical interactions with nW level powers even in the presence of transit-time dephasing rates much larger than the intrinsic linewidth. We demonstrate nonlinear absorption and V-type electromagnetically induced transparency with cw powers below 10 nW, comparable to the best results in any Rb-optical waveguide system. The good performance and flexibility of the Rb-TNF system makes it a very promising candidate for ultralow power resonant nonlinear optical applications.
ABSTRACT
Recently, the design of a white-light cavity has been proposed using negative dispersion in an intracavity medium to make the cavity resonate over a large range of frequencies and still maintain a high cavity buildup. This Letter presents the first demonstration of this effect in a free-space cavity. The negative dispersion of the intracavity medium is caused by bifrequency Raman gain in an atomic vapor cell. A significantly broad cavity response over a bandwidth greater than 20 MHz has been observed. A key application of this device would be in enhancing the sensitivity-bandwidth product of the next generation gravitational wave detectors that make use of the so-called signal-recycling mirror.
