Jesper Munch

Analysis of system trade-offs for terahertz imaging

In this paper we analyse the trade-offs for a terahertz imaging system and discuss implementation of a terahertz micro antenna array for imaging. We also describe applications of terahertz imaging and improvements in the signal processing.

Injection-seeded, single-frequency, Q-switched erbium:glass laser for remote sensing

We have built and characterized an injection-seeded, Q-switched, flash-lamp-pumped, eye-safe Er:glass laser that is suitable for coherent remote sensing. The output of the device is a 400-ns, single-frequency, transform-limited pulse of 1 mJ at 1.552 mum.

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.

Compact, holographic correction of aberrated telescopes

We demonstrate a compact reflector telescope design that incorporates the holographic correction of a large, low-quality primary spherical mirror by using a laser beacon located at the center of curvature. The simple design makes use of conventional optics and is easily scalable to much larger apertures. Experimental results indicate diffraction-limited performance from a heavily aberrated 0.5-m-diameter spherical mirror.

Variable optical delay line with diffraction-limited autoalignment

We demonstrate a novel type of variable, optical delay line that ensures diffraction-limited parallelism and collinearity in the delayed beam and is independent of the mechanical quality of the translation stage.

Phase-aberration correction with dual liquid-crystal spatial light modulators

A phase-aberration-correction system that uses high-resolution, twisted nematic liquid-crystal spatial light modulators in a Mach-Zehnder interferometer is presented. A correction algorithm is described and experimentally verified by use initially of one liquid-crystal panel. Phase aberrations are successfully removed by a single liquid-crystal panel, but unacceptably high amplitude variation is introduced into the wave front because of the phase-amplitude coupling of the spatial light modulator. A second panel is used to remove the amplitude modulation. The modified optical system with a multiplicative architecture is described, and results are presented that show the correction of phase aberrations with an amplitude variation of less than 10%.

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.

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.

Variation in the coherence length of a phase conjugating oscillator

Abstract The coherence length of a Nd:YAG laser with an intra-cavity SBS cell has been investigated interferometrically. It is shown that the coherence length decreases with increasing output pulse energy, and is limited by the pulse width when the pulse energy is much higher than the lasing threshold. Coherence lengths as short as 16 mm have been measured for pulse widths of 50 ns and energies ⩾20 mJ.