High mechanical Q-factor measurement of Si using a 3D cantilever support.

Thermal noise in test mass substrates and coatings is a significant noise contribution in the detection band of current and proposed future gravitational wave detectors. Substrate thermal noise can be reduced by using high mechanical Q-factor materials and cooling the test mass mirrors. Silicon is a promising potential candidate for the next generation detector test masses.

A multi-orientation low-frequency rotational accelerometer.

We present a low frequency rotational accelerometer coined ALFRA with a few nrad/Hz readout sensitivity above 20 mHz and 0.1 nrad/Hz above 50 mHz. The ALFRA is a beam-balance style rotation sensor, which pivots about a cross flexure designed to allow mounting with any orientation, the axis of the pivot determining which rotational component is measured.

Six degrees of freedom vibration isolation with Euler springs.

A novel design allows column springs in Euler buckling mode to be laterally stable and thus provides vibration isolation in six degrees of freedom. Analytical models of the stiffness were used to develop a design with a vertical resonance of 1.13 Hz, a horizontal resonance of 1.

Characterization of a self-damped pendulum for vibration isolation.

In many sensitive measurement systems such as gravitational wave detectors, multistage low-loss vacuum-compatible suspension chains are required to effectively isolate the test mass from seismic disturbances. These chains usually have high quality factor normal modes which require damping. A technique termed "self-damping" in which the motion of orthogonal modes of the same stage mass is deliberately viscously cross-coupled to each other-thereby damping both modes-was engineered into the suspension chains used in an 80 m suspended high-power optical cavity.

A laser walk-off sensor for high-precision low-frequency rotation measurements.

We present an optical walk-off sensor with an angular sensitivity of a few nrad/Hz above 1 mHz and 0.4 nrad/Hz above 100 mHz. This experiment furthers previous research into the walk-off sensor capabilities through an improved input laser, reduction in air optical travel length, and position control on photo-diodes.