Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 4 of 4
Full-Text Articles in Physics
Study Of The Effects Of Cavity Mode Spacing On Mode-Hopping In Iii–V/Si Hybrid Photonic Crystal Lasers, Praveen K.J. Singaravelu, Sharon M. Butler, Robert N. Sheehan, Alexandros A. Liles, Stephen P. Hegarty, Liam O'Faolain
Study Of The Effects Of Cavity Mode Spacing On Mode-Hopping In Iii–V/Si Hybrid Photonic Crystal Lasers, Praveen K.J. Singaravelu, Sharon M. Butler, Robert N. Sheehan, Alexandros A. Liles, Stephen P. Hegarty, Liam O'Faolain
Cappa Publications
We present a design methodology for hybrid lasers to realise mode-hop free operation by controlling the cavity mode spacing. In this study, a compact hybrid photonic crystal laser (H-PhCL) was employed which allowed a reduction of the Fabry–Perot length of the laser cavity and eliminated the need for an active mode stabilisation mechanism in order to realise mode-hop free operation. The H-PhCL was formed by butt-coupling a reflective semiconductor optical amplifier (RSOA) with a two-dimensional silicon (Si) photonic crystal (PhC) cavity. Continuous stable single frequency operation with >40 dB side-mode suppression ratio (SMSR) of the laser was achieved for gain …
Investigating The Use Of Ultraviolet Light Emitting Diodes (Uv-Leds) For The Inactivation Of Bacteria In Powdered Food Ingredients, Laura Nyhan, Milosz Przyjalgowski, Liam O'Faolain, Máire Begley, Michael Callanan
Investigating The Use Of Ultraviolet Light Emitting Diodes (Uv-Leds) For The Inactivation Of Bacteria In Powdered Food Ingredients, Laura Nyhan, Milosz Przyjalgowski, Liam O'Faolain, Máire Begley, Michael Callanan
Cappa Publications
The addition of contaminated powdered spices and seasonings to finished products which do not undergo further processing represents a significant concern for food manufacturers. To reduce the incidence of bacterial contamination, seasoning ingredients should be subjected to a decontamination process. Ultraviolet light emitting diodes (UV-LEDs) have been suggested as an alternative to UV lamps for reducing the microbial load of foods, due to their increasing efficiency, robustness and decreasing cost. In this study, we investigated the efficacy of UV-LED devices for the inactivation of four bacteria (Listeria monocytogenes, Escherichia coli, Bacillus subtilis and Salmonella Typhimurium) on a plastic surface and …
Lithium Niobate Fabry-Perot Microcavity Based On Strip Loaded Waveguides, Maria V. Kotlyar, Simone Iadanza, Liam O'Faolain
Lithium Niobate Fabry-Perot Microcavity Based On Strip Loaded Waveguides, Maria V. Kotlyar, Simone Iadanza, Liam O'Faolain
Cappa Publications
In this work, we combine Lithium Niobate on insulator with a silicon nitride layer to form strip-loaded waveguides that can take advantage of the strong nonlinear optical coefficients of lithium niobate and of the high refractive contrast and ease of processing of silicon nitride. We describe the design and fabrication of a Fabry-Perot cavity formed by Distributed Bragg Reflectors. We discuss the design trade-offs implicit in the realisation of such microcavities of this nature and demonstrate an experimental quality factor of 2300, which is to our knowledge, the highest experimentally reported result for such type of waveguide based Fabry-Perot cavity.
A Dual-Functionality Metalens To Shape A Circularly Polarized Optical Vortex Or A Second-Order Cylindrical Vector Beam, Victor V, Kotlyar, Sergey S. Stafeey, Anton G. Nalimov, Liam O'Faolain, Maria V. Kotlyar
A Dual-Functionality Metalens To Shape A Circularly Polarized Optical Vortex Or A Second-Order Cylindrical Vector Beam, Victor V, Kotlyar, Sergey S. Stafeey, Anton G. Nalimov, Liam O'Faolain, Maria V. Kotlyar
Cappa Publications
Using e-beam lithography and reactive ion beam etching of a 120 nm amorphous silicon film, we fabricate a 30-µm spiral metalens that has a very short focal length that is equal to the incident 633 nm wavelength (numerical aperture about 1) and is composed of 16-sectored subwavelength binary gratings with a 220 nm period. Its unique feature is that the metalens generates a left-hand circularly polarized optical vortex with topological charge 2 when illuminated by a left-hand circularly polarized light but generates a cylindrical second-order vector beam when illuminated by linearly polarized light. Both for linearly and circularly polarized light, …