1,164 research outputs found
A linearly polarised, pulsed Ho-doped fiber laser
No full textAbstract not availableSophie Hollitt, Nikita Simakov, Alexander Hemming, John Haub and Adrian Carte
Data set for Thermally-guided Yb-doped fiber-rod amplifier and laser
No full textData set for the paper Smith, C. R., Simakov, N., Hemming, A., & Clarkson, W. A. (2019). Thermally-guided Yb-doped fiber-rod amplifier and laser. Applied Physics B: Lasers and Optics, 125(32), 1-10. DOI: 10.1007/s00340-018-7126-3</span
Efficient, low threshold, cryogenic Ho:YAG laser
No full textPublished 18 May 2016Abstract not availableMiftar Ganija, Nikita Simakov, Alexander Hemming, John Haub, Peter Veitch, and Jesper Munc
A new guide star laser using optimized injection mode-locking
No full textAlso cited as: Proceedings of the SPIE; vol. 7015Abstract not availableJesper Munch, Thomas P. Rutten, Nikita Simakov, Murray Hamilton, Céline d'Orgeville, Peter J. Veitc
A pulsed guide star laser can be the brightest
No full textWe report on a numerical model and supporting experiments to show that a high peak power, pulse burst, Na guide-star waveform, suitable for use with adaptive optics systems requiring dynamic refocusing to avoid guide star elongation, is capable of producing a return comparable to conventional guide star laser of comparable output power. The predictions from our numerical model using coherent pumping by short, high peak power pulses, or so-called π-pulse pumping, indicate that very bright fluorescence returns can be achieved in this regime. This is supported by experimental results where fluorescence is observed in alkali atoms (cesium) using variable input power and pulse lengths. The model is used to predict very bright Na guide stars, using short pulses to excite most of the Na atoms available, followed by sufficient time to let them decay. © 2010 SPIE.Nikita Simakov, Murray Hamilton, Peter J. Veitch and Jesper Munc
A bright, pulsed, guide star laser for very large telescopes
No full textWe demonstrate for the first time the practical feasibility of a new sodium guide star laser with a pulsed burst output of sufficient energy at 589nm to be useful for current applications and readily scalable to meet future requirements. We describe complete experimental design verification results of the pulse burst laser concept, optimized to eliminate guide-star elongation issues and to meet all requirements for Multi Conjugate Adaptive Optics (MCAO) for future extremely large ground-based telescopes (ELTs). It makes use of sum frequency generation (SFG) of two, Q-switched, injection mode-locked, wavelength stabilized Nd:YAG lasers, producing a macro-micro, pulse-burst output which is optimized in power and bandwidth to maximize the fluorescence from the high altitude sodium layer. © 2010 SPIE.Jesper Munch, Murray Hamilton, David Hosken, Nikita Simakov and Peter Veitc
Thermally-guided fiber-rod laser
No full textFiber and bulk lasers form two distinct classes of solid-state laser, both of which have achieved tremendous success in various arenas, but they are not without their limitations. The long, thin geometry of a fiber allows excellent heat dissipation, which combined with a waveguiding structure provides stronger resilience to thermally-induced mode distortions than in bulk lasers, allowing diffraction-limited single-mode operation at multi-kW power levels in continuous-wave mode. However, the threshold for deleterious non-linear effects and laser-induced damage in fibers is generally much lower than bulk systems, owing to very tight beam confinement over a long interaction length, placing stringent limitations on pulsed performance in fibers
Development of components and fibres for the power scaling of pulsed holmium-doped fibre sources
No full textIn this thesis the optimisation and peak power scaling of pulsed holmium-doped fibre lasers were investigated with the aim of demonstrating a fibre gain medium that is able to address the requirements of applications that currently rely on bulk crystalline Ho:YAG or Ho:YLF solutions.Conventional fibre processing techniques such as cleaving, end-capping and component fabrication were improved upon using CO2 laser processing. The resulting components and processes are also characterised under high power operating conditions and have enabled subsequent experimentation and demonstrations.Holmium-doped silica fibres were fabricated and characterised with the aim of reducing impurity contaminations, improving composition and achieving efficient operation at 2.1 μm. These fibres were characterised passively using transmission spectroscopy and actively in a laser configuration. The most efficient of these compositions operated with a 77% slope efficiency in a core-pumped laser up to average powers of 5 W and was then processed into a double-clad geometry. The cladding-pumped fibre was operated at 70 W output power with a slope efficiency of 67% and represents one of the highest power and most efficient cladding-pumped holmium-doped fibres demonstrated to-date.Small-signal amplifiers utilising both thulium-doped and holmium-doped silica fibres were demonstrated. These amplifiers offered a broad wavelength coverage spanning 490 nm at 15 dB gain from 1660 nm – 2150 nm. This remarkably broad wavelength coverage is attractive for a large number of disciplines looking to exploit this previously difficult-to-reach wavelength range.In addition to these devices, the average power and peak power scaling of 2 μm fibre sources was investigated. A thulium-doped fibre laser operating at 1950 nm with >170 W of output power, a tuneable holmium-doped fibre laser producing >15 W over the wavelength span from 2040 nm – 2171 nm and a pulsed holmium-doped fibre amplifier with >100 kW peak power at 2090 nm are reported.Finally we review the requirements for efficient scaling of mid-infrared optical parametric oscillators and analyse the non-linear effects that arise when attempting to scale the peak power in silica fibres in the 2 μm spectral region. We implement a range of strategies to reduce the onset of nonlinear effects and demonstrate a holmium-doped fibre amplifier with peak power levels exceeding 36 kW in a 5 ns pulse with a spectral width of <1 nm. This represents the highest spectral density achieved for nano-second pulse duration from pulsed holmium-doped fibre sources. This preliminary result provides an excellent platform for further peak power scaling and also in replacing conventional Q-switched Ho:YAG lasers.</p
Tuneable operation of core and cladding pumped holmium fibre lasers
No full textHolmium fibre lasers are required for remote sensing, LIDAR and some medical applications. In comparison to thulium fibre lasers, the holmium emission provides efficient access to the 2070 nm - 2150 nm wavelength range. We present the first report of the tuneable range of a resonantly, cladding pumped holmium fibre laser. This is compared to the tuning range of a core pumped holmium doped fibre
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