PhD Projects and Scholarship in UWA Australia

PhD Projects and Scholarship

The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA), in partnership with the US LIGO Laboratory, is developing technology which, for the first time, will allow gravitational wave detectors to detect known sources of gravitational waves at a frequent rate. By increasing the range of the detectors 10-folds, 1000 times as many sources will be detectable but this requires very intense laser beams to reduce the quantum shot noise in the detectors. ACIGA is a consortium of several Australian universities (UWA, ANU, University of Adelaide and others). The ACIGA’s high optical power facility is located at Gingin about one hour’s drive from Perth city centre.

Our projects are suitable for experimentally talented physics or engineering (both mechanical and electronic) students. Successful candidates will develop skills in advanced optics, control systems, vibration isolation and precision mechanics in the context of one of the most exciting frontiers of fundamental physics and astrophysics. Project work will be focused on the Gingin facility but will include work operating the LIGO detectors. On completion there will be opportunities to play a major role in the upgrading of LIGO, and in the development of the planned long baseline detector at Gingin.

Proposed PhD projects (for 2008)

1. Negative dn/dt thermal compensation.

High optical power interferometers use negative thermal gradients created by laser heating to compensate for the positive thermal lensing due to absorbed power in the test masses. A negative dn/dt material allows much better compensation but there are several technical issues associated with potential compensation materials. This project will begin by assessing the performance of crystalline quartz and then assess various advanced materials which could be much superior.
2. Two frequency stable optical locking of long cavities

It has recently been shown that radiation pressure can be used to create stable rigid optical "rods" between suspended mirrors if two laser frequencies are used in the optical cavity. The stiffness of the optical rod can exceed the stiffness of diamond. This technique offers far reaching possibilities from optically stabilised rigid structures in space to improved low frequency sensitivity in laser interferometers. This project will explore the new techniques and test them on 80 meter high optical power cavities.
3. Low frequency noise reduction using optical bar techniques

This project aims to develop a practical technique for enhancing the low frequency of laser interferometers using optical spring techniques. It is related to project (2) above, but need not use two frequencies. The goal in this project is to define a practical low frequency optical bar readout first for a single optical avity and then for an interferometer.
4. CO2 laser adaptive thermal compensation

All high optical power cavities (except for cryogenic systems) require thermal compensation to correct the thermal wavefront distortion. An ideal system would use a closed loop between a wavefront sensor and an actuator consisting of a CO2 laser pattern on the test mass. There is considerable difficulty in creating a continuously adaptive CO2 laser beam pattern that will not introduce noise. This project will investigate various technologies for defining and creating the desired spatial intensity pattern in the laser pattern, and then design and fabricate a prototype system.
5. Lock acquisition at high optical power

At high optical power radiation pressure forces creates difficulty in locking lasers to the cavity. This project will compare experimental and theoretical lock acquisition in optical cavities as a function of stored optical power. Effects that must be allowed for include torsional instability, longitudinal radiation pressure forces and the rapid growth of parametric oscillations. The latter must be damped electrostatically or by optical feedback.
6. Depolarisation and Photothermal Noise in High Optical Power systems.

This project will involve analytic theory and Finite Element and FFT modelling of photoelastic phenomena in high optical power systems. This will be followed by experiments on depolarisation from thermal lensing and photothermal noise from laser intensity fluctuations. This has applications to Advanced Laser Interferometer gravitational wave detectors and to third generation interferometers which may use coatingless optical cavities.

For expressions of interest, please contact:

* Prof. David Blair ()
* Dr. Li Ju ()
* Dr. Chunnong Zhao ()

Scholarships

Australian and New Zealand citizens and Australian permanent residents are legible to apply UWA post graduate Scholarship http://www.scholarships.uwa.edu.au/home/postgrad

Application for scholarship for 2008 deadline is October 2007

International students can apply for International Postgraduate Research Scholarships (IPRS) and Scholarships for International Research Fees (SIRFs) http://www.scholarships.uwa.edu.au/home/postgrad/international/iprs

Application for 2008 deadline: 15 August 2007.

Outstanding candidates in receipt of Australian Postgraduate Awards or University Postgraduate Awards may be eligible to receive supplementary scholarships. Tutoring and part-time teaching may also be available for additional income.

Academic visitors: Many of our PhD students first visit here as academic visitors. We have had students and visitors from China, India, France, Chile, Austria, Poland, Singapore, Germany, Romania and USA. Visitors usually receive living allowance equal to the value of a PhD scholarship.