Vibration control for optical interferometry

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Synopsis

Develop an active vibraiton isolation platform to provide a quiet, small displacement environment for high precision inteferometry.

Description

Laser-interferometric gravitational wave detectors, such as those of the Laser Interferometer Gravitational Wave Observatory (LIGO), are the most sensitive position sensors ever built. Since the first detection of gravitational waves in 2015, the quest to further improve detector range and sensitivity has been in full swing. The ANU Centre for Gravitational Astrophysics has installed hardware at the current LIGO detectors and, as part of the national ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), continues to develop instrumentation to enhance the sensitivity of gravitational wave detectors worldwide.

Optical interferometry is used for high-precision displacement sensing, such as in gravitational wave detection. Achieving these measurements requires ever-quieter environments in which external noise is effectively suppressed. One way to reduce mechanical motion is to use low-noise seismometers to stabilise a work platform. A seismometer based on a single-axis mechanical pendulum measures the motion of the platform and produces a signal; this signal is fed to an actuator that reduces the platform's motion, creating a mechanically quiet environment.

In this project, the student will begin by investigating the horizontal motion of this seismometer's mechanical system using an optical displacement sensor. Measuring and characterising the system will allow its performance to be compared against the mechanical model. Along the way, the student will develop skills in electronics, optics, mechanical design and control systems. With sufficient progress, the performance of the single-axis seismometer may also be compared to that of a commercial seismometer, with results presented in a research paper.

Find out more by following the Further Information link below, or by visiting the Centre for Gravitational Astrophysics website.

Required background

Basic knowledge of optics and electronics is required, with experience in Matlab a bonus.

Research fields