T violation and microhertz resolution in a ring laser.

A He-Ne ring laser has given the Earth-rotation-induced Sagnac frequency to a precision of 1 microHz, or 2 parts in 10(8), 2 x 10(-21) of the laser frequency. Because the beat frequency in a ring laser originates in either timereversal or (with a more complicated polarization geometry) parity-violating effects, such systems have the potential of detecting ultrasmall symmetry violations.

Sideband analysis and seismic detection in a large ring laser.

Aring laser unlocked by the Earth's Sagnac effect has attained a frequency resolution of 1 part in 3 × 10(21) and a rotational resolution of 300 prad. We discuss both theoretically and experimentally the sideband structure of the Earth rotation-induced spectral line induced in the microhertz-hertz region by frequency modulation associated with extra mechanical motion, such as seismic events. The relative sideband height is an absolute measure of the rotational amplitude of that Fourier component. An initial analysis is given of the ring laser record from the Arthur's Pass-Coleridge seismic event of 18 June 1994.

Origins of fundamental limits for reflection losses at multilayer dielectric mirrors.

Fundamental limits on reflection losses are set by internal material losses associated with the Urbach tail near a band gap and by thermodynamic density fluctuations in fabrication. In materials such as SiO(2) and TiO(2), these limits are of the order of parts in 10(9). The current quality of supercavity mirrors, in contrast to that of optical fibers, is still far from these limits because of purely technological limitations in surface preparation and in the reduction of impurity levels. Overcoming these would greatly benefit, for example, Fabry-Perot interferometers, ring lasers, and gravitational wave detectors.

Power transfer of an astigmatic Gaussian beam to a stigmatic optical system.

Simple transfer optics are used, employing a spherical rather than cylindrical lens, to complete the power transfer resulting in a small power loss for a wide range of astigmatism.

Stability of planar ring lasers with mirror misalignment.

We consider an active cavity defined by a geometrically symmetric ring of N mirrors, each of which may have an arbitrary radius. The beam steering imposed by all possible mirror misalignment parameters is shown to diverge if the radii of curvature R(i) of the mirrors satisfy two constraints of the form K(N)({R(i)}) = 2. By comparison, the standard conditions for the stability of rays departing from the design path in a perfectly aligned ring have the form |K(N)({R(i)})|