"Next Challenges in Gravitational Wave Astronomy" by David Blair
Abstract: Gravitational wave physicists have now detected gravitational waves from ten coalescing black holes and an inspiralling neutron star binary. These are the tip of the iceberg. Within the Hubble volume black holes are coalescing roughly once every five minutes, while neutron stars coalesce four times per minute. The signals detected so far are dominated by the inspiral phase in the frequency band 30-300Hz. The rich physics of neutron star merger, and of the collapse of nuclear matter to form black holes, occurs in the frequency band 1-4kHz. New interferometers have been proposed capable of observing these events. They will require the use of very high optical power interferometers combined with optical squeezing, and are limited entirely by quantum noise. Ideas for such a detector in Australia will be presented. The new detectors would be the first able to probe the interior structure of neutron stars, the gravitational collapse of matter and the formation of an event horizon.
"Micromechanical resonators for optomechanics and improved gravitational wave detectors" by Li Ju (On behalf of OzGrav-UWA instrumentation group)
Abstract: The concept of a white light cavity for enhanced signal recycling bandwidth in gravitational wave detectors was first proposed 20 years ago. Initial proposals proposed the use of atomic media to achieve the negative dispersion required. When this approach was shown to have serious noise limits, the concept of an optomechanical negative dispersion filter was proposed. Classical demonstrations showed that negative dispersion was attainable but the requirements on the losses in the optomechanical system are extremely challenging. It requires the creation of ultrahigh quality factor micro-optomechanical resonators. One approach is to create micro-optomechanical resonators through optical trapping. Combined with blue detuning, and servo control, small scale systems can be envisaged that would allow significant improvement in the high frequency performance of gravitational wave detectors. In this talk I will describe research at the University of Western Australia where we are exploring many solutions, including micromechanical cat-flap resonators.
Host: M. Aspelmeyer