1,720,967 research outputs found
Pulsed laser deposition of thin-film oxides for waveguide lasers
No full textPulsed laser deposition (PLD) is a technique for depositing materials and PLD displays versatility and high growth rates. It can be used to grow active single-crystal materials, which can be used as planar waveguide lasers. During PLD, particulates can be embedded into the growing film, which can reduce the planar waveguide lasers optical-to-optical efficiency and degrade the physical characteristics of a grown film. The experiments presented in this thesis focus on reducing the density of particulates in PLD-grown films and using this knowledge to grow high quality, novel materials.Three particulate reduction techniques were investigated including a shadow-mask, segmented targets and bi-directional ablation. All of these techniques reduced the particulate density and bi-directional ablation was implemented as the new standard ablation regime. This novel technique increased target utilisation by 50%, target lifetime by 100% and demonstrated an average particulate density reduction of 80%. As a direct result of bi-directional ablation, films with losses down to 0.12 dB/cm were realised. The versatility of PLD was exploited to tune the lattice constant of a mixed-sesquioxide film to demonstrate a <0.1% lattice mismatch with sapphire. Waveguiding was realised for the first time in a 3% Yb-doped sapphire waveguide, a material that is impossible to grow via traditional crystal growth methods. A Yb:LuAG laser with cladding layers was demonstrated, for the first time with PLD, with output powers of 3.3 W. Using bi-directional ablation, an Er:YGG film was grown and 3.46 dB of gain was realised in a channel waveguide geometry. Previous attempts had not achieved any such gain due to high losses.The particulate reduction technique demonstrated in this thesis and the subsequent exploitation, pave the way for PLD as a commercially viable technique for waveguide fabrication. Without the drawback of high particulate densities, high quality optical devices can be fabricated via PLD that would compete with other growth techniques
Yb:LuAG double-clad planar waveguide laser
No full textDataset for the paper "Characterisation and laser performance of a Yb:LuAG double-clad planar waveguide grown by pulsed laser deposition" published in Applied Physics B. https://doi.org/10.1007/s00340-019-7314-9</span
Dataset for Pulsed laser deposition of crystalline garnet waveguides at a growth rate of 20 µm per hour
No full textDataset supports:
Grant-Jacob, J., et al (2017). Pulsed laser deposition of crystalline garnet waveguides at a growth rate of 20 µm per hour. Surface & Coatings Technology. DOI: 10.1016/j.surfcoat.2017.12.008</span
Particulate reduction in ternary-compound film growth via pulsed laser deposition from segmented binary-targets
No full textDataset supporting:
Grant-Jacob, J. et al. (2018). Particulate reduction in ternary-compound film growth via pulsed laser deposition from segmented binary-targets. Materials Research Express. </span
Pulsed-laser-deposited Yb:YAG planar-waveguide amplifier
No full textRecent advances in the development of a PLD-grown Yb:YAG planar waveguide laser and amplifier will be presented. Laser output power of 21 W with 70% slope efficiencies was achieved. >20dB amplification in the small signal regime and >30W output power in the saturated amplifier regime were also demonstrated
Quantitative analysis of bi-directional ablation in pulsed laser deposition
No full textPulsed laser deposition (PLD) is a versatile technique that can be used to produce thin-film crystalline materials. Here, we present the quantification of film quality improvements and the reduction of target LIPSS (laser induced periodic surface structure) obtained via the implementation of a bi-directional ablation technique. We demonstrate a tenfold reduction in particulate density, twofold reduction in surface roughness, and a fivefold reduction to waveguide losses in YGG (yttrium gallium garnet) films
Dataset for Particulate reduction in PLD-grown crystalline films via bi-directional target irradiation
No full textData for journal article:
Prentice, J. J., et al (2018). Particulate reduction in PLD-grown crystalline films via bi-directional target irradiation. Applied Physics A.
DOI:10.1007/s00339-019-2456-5</span
Particulate reduction in PLD-grown crystalline films via bi-directional target irradiation
No full textWe present a novel variation of the pulsed laser deposition technique, aimed at reducing the number of particulates produced and consequently the linear propagation loss observed in the resulting crystal waveguides. The approach relies upon configuring the system to effectively provide bi-directional ablation, whereby the incidence angle of the fixed pulsed-laser-beam with respect to the target surface changes sign, depending upon the rotation angle and position of the target. Such an alternating ablation direction is intended to reduce the buildup of undesirable periodic surface structures, such as directional cones, believed to be a major source of particulates within the growing film. We show that targets ablated using this technique have fewer directional structures and a decreased surface roughness. Furthermore, using PLD-grown Y3Ga5O12 as the exemplar crystal film, we compare growths with uni- and bi-directional ablation and demonstrate reduction from ~ 0.9 dB/cm to ~ 0.23 dB/cm in the average waveguide propagation losses via the latter
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