Murray Hamilton

Power scalable TEM/sub 00/ CW Nd:YAG laser with thermal lens compensation

We present finite-element analysis and experimental results to validate our approach for building high-power single-mode Nd:YAG lasers. We show that the thermooptical and thermomechanical properties of a slab laser can be controlled. This is essential for the use of the proposed unstable resonator, We include demonstration of an efficient subscale laser operating at 20 W TEM/sub 00/.

High-power diode-laser-pumped CW solid-state lasers using stable-unstable resonators

We present a novel design for an efficient, high power (>100 W), continuous-wave (CW) Nd:YAG laser with diffraction-limited performance. It uses side-pumped, sidecooled, zigzag slab which is incorporated in a stable-unstable resonator that has a variable reflectivity output coupler. A geometric magnification of at least 1.3 in the unstable direction can be achieved. Modeled performance characteristics are presented.

A compact injection-locked Nd:YAG laser for gravitational wave detection

We have designed and characterized a diode-pumped injection-locked Nd:YAG laser suitable for precision metrology. The laser uses a simple side-pumped laser architecture and is compact, efficient, stable, and scalable. The frequency stability of the injection-locked slave laser is shown to be limited by the monolithic master oscillator and its intensity noise is 4/spl times/10/sup -6/ Hz/sup -1/2/ at 1 kHz.

High-power Nd:YAG lasers using stable–unstable resonators

The development of a power-scalable diode-laser-pumped continuous-wave Nd:YAG laser for advanced long-baseline interferometric detectors of gravitational waves is described. The laser employs a chain of injection-locked slave lasers to yield an efficient, frequency-stable, diffraction-limited laser beam.

Stabilized master laser system for differential absorption lidar.

Wavelength accuracy and stability are key requirements for differential absorption lidar (DIAL). We present a control and timing design for the dual-stabilized cw master lasers in a pulsed master-oscillator power-amplifier configuration, which forms a robust low-cost water-vapor DIAL transmitter system. This design operates at 823 nm for water-vapor spectroscopy using Fabry-Perot-type laser diodes. However, the techniques described could be applied to other laser technologies at other wavelengths. The system can be extended with additional off-line or side-line wavelengths. The on-line master laser is locked to the center of a water absorption line, while the beat frequency between the on-line and the off-line is locked to 16 GHz using only a bandpass microwave filter and low-frequency electronics. Optical frequency stabilities of the order of 1 MHz are achieved.

Technology developments for ACIGA high power test facility for advanced interferometry

The High Optical Power Test Facility for Advanced Interferometry has been built by the Australian Consortium for Interferometric Gravitational Astronomy north of Perth in Western Australia. An 80 m suspended cavity has been prepared in collaboration with LIGO, where a set of experiments to test suspension control and thermal compensation will soon take place. Future experiments will investigate radiation pressure instabilities and optical spring effects in a high power optical cavity with ~200 kW circulating power. The facility combines research and development undertaken by all consortium members, whose latest results are presented.

Development of Power Scalable Lasers for Gravitational Wave Interferometry

The design approach for intermediate and high power lasers for gravitational wave interferometry including TAMA 300 is discussed with latest laser performance results.

Second-generation laser interferometry for gravitational wave detection: ACIGA progress

Reasonable event rate gravitational wave astronomy in the audio frequency detection band will require improving the sensitivity of long-baseline interferometer-based gravitational wave detectors currently under construction by at least a factor of 10. In this summary we report research being carried out by the Australian Consortium for Interferometric Gravitational Astronomy towards this end.

Injection Mode-Locked, Q-Switched Nd:YAG Laser at 1319 nm

There is currently no laser source that can provide both efficient excitation of mesospheric sodium and allow removal of the effects of guide-star elongation, as required for multi-conjugate adaptive optics in next-generation extremely large telescopes. We describe a Q-switched 1319 nm Nd:YAG laser that is mode-locked by injecting a short pulse into the Q-switched laser. It produces Q-switched mode-locked pulses that are synchronized to an external source. We also discuss how such pulses at 1064 nm and 1319 nm can be used to generate pulsed sodium-resonant guide stars via sum frequency generation, and thus satisfy the above requirements.

A new guide star laser using optimized injection mode-locking

We describe a new, improved approach for sodium guide-star lasers for the correction of atmospheric aberrations in telescopes, which satisfies all current requirements for advanced pulse burst waveforms. It makes use of sum frequency generation (SFG) of two pulsed, Q-switched, injection mode-locked Nd:YAG lasers, resulting in a macro-micro pulse-burst output, optimized in power and bandwidth to maximize the fluorescence from the high altitude sodium layer. The approach is robust and power scalable and satisfies the requirements for Multi Conjugate Adaptive Optics (MCAO) for current and future telescopes, including extremely large ground telescopes (ELTs). It is also adaptable for advanced design options. Here we describe the approach in detail, the results from critical design verification experiments, the current status and plans for further work required to demonstrate a complete sodium guide-star laser.