1,720,973 research outputs found
Wideband mid-infrared group IV photonic devices and platforms
No full textMid-infrared group IV photonics is a field which, by adapting techniques from silicon photonics at visible and near-infrared wavelengths and using mature semiconductor fabrication processes, could establish an enabling technology for a diverse range of applications in numerous areas. In particular, integrated photonic sensors could take advantage of the characteristic absorptions of many chemicals at mid-infrared wavelengths, due to strong fundamental molecular vibrations in this region. Such “lab-on-a-chip” devices would be applied to areas like medical diagnostics and environmental monitoring. To develop complex mid-infrared photonic integrated circuits, a set of core building-block components are required. Currently, the components in mid-infrared group IV photonics are limited to operating at relatively narrow wavelength ranges. This lack of spectral bandwidth is not an issue for some applications, but to unlock the full potential of the field, it is essential to develop wideband devices. The operating wavelength range of mid-infrared devices may be limited by absorptions of the material platform or the geometry of the component; this work considers both to increase the available spectral bandwidth. Silicon-on-insulator waveguides with propagation losses ∼1.5 dB/cm are shown to only support the fundamental mode over an octave of frequency, as an experimental demonstration of a technique that in principle will be applicable to much of the mid-infrared range. Beam splitters were fabricated on silicon-on-insulator platforms with low insertion losses and high performance over a bandwidth of 3.1 − 3.7 μm: multimode interferometers are shown with an insertion loss of <1 dB and imbalance of <0.5 dB; and an insertion loss of ∼0.2 dB was achieved for 50/50 Y-splitters. Further, considering material platforms, silicon membrane devices have been successfully transfer printed onto a high-transparency zinc selenide substrates, to develop waveguides without substrate absorption losses
Dataset for the thesis 'Wideband mid-infrared group IV photonic devices and platforms'
No full textThis dataset supports the thesis:
Callum John Stirling
Wideband mid-infrared group IV photonic devices and platforms
The file 'Dataset_for_WidebandG4_thesis.xlsx' contains all simulation and experimental data.</span
A nobel cause: public engagement and outreach
No full textShowcasing cutting edge physics research to school children and the general public humanizes ‘the scientist’. This can help towards removing stereotypes and enabling greater diversity in physics. Here we share some of the lessons learnt and activities conducted at the University of Southampton to achieve this goal
Sub-wavelength gratings in silicon photonic devices for mid-infrared spectroscopy and sensing
No full textMid-infrared spectroscopy enabled by silicon photonics has received great interest in recent years as a pathway for a scalable sensing technology. The development of such devices would realise inexpensive and accessible instrumentation for a wide variety of uses over numerous fields. However, not every sensing application is the same; to produce sensors for real-world scenarios, engineers need flexibility in device design but also need to maintain compatibility with scalable fabrication processes. Sub-wavelength gratings can offer a solution to this problem, as they enable the engineering of optical properties using standard fabrication techniques and without requiring new materials. By using sub-wavelength gratings, specific design approaches can be tailored to different applications, such as increasing the interaction of a sensor with an analyte or broadening the bandwidth of an integrated photonic device. Here, we review the development of sub-wavelength grating-based devices for mid-infrared silicon photonics and discuss how they can be exploited for spectroscopic and sensing devices
Dataset in support of the paper 'High-efficiency Mid-infrared Wavelength Conversion in Silicon Waveguides'
No full textThis dataset contains:
The raw data of FIG.1c is 'fig1c.xlsx'.
The raw data of FIG.3a is 'fig3a.xlsx'.
The raw data of FIG.3b is 'fig3b.xlsx'.
The raw data of FIG.4a is 'fig4a.csv'.
The raw data of FIG.4b is 'fig4b.xlsx'.
Paper has been accepted by APL Photonics</span
Dataset for: Mid-infrared silicon-on-insulator waveguides with single-mode propagation over an octave of frequency
No full textExperimental and simulation data for the paper:
Callum J. Stirling, Wei Cao, Jamie D. Reynolds, Zhibo Qu, Thomas D. Bradley, Lorenzo Mastronardi, Frederic Y. Gardes, Goran Z. Mashanovich, Milos Nedeljkovic. (2021). Mid-infrared silicon-on-insulator wavegudes with single-mode propagation over an octave of frequency, Optics Express</span
Mid-infrared silicon-on-insulator waveguides with single-mode propagation over an octave of frequency
No full textIncreasing the working optical bandwidth of a photonic circuit is important for many applications, in particular chemical sensing at mid-infrared wavelengths. This useful bandwidth is not only limited by the transparency range of waveguide materials, but also the range over which a waveguide is single or multimoded for predictable circuit behaviour. In this work, we show the first experimental demonstration of "endlessly single-mode" waveguiding in silicon photonics. Silicon-on-insulator waveguides were designed, fabricated and characterised at 1.95 μm and 3.80 μm. The waveguides were shown to support low-loss propagation (1.46 ± 0.13 dB/cm loss at 1.95 μm and 1.55 ± 0.35 dB/cm at 3.80 μm) and single-mode propagation was confirmed at 1.95 μm, meaning that only the fundamental mode was present over the wavelength range 1.95 - 3.80 μm. We also present the prospects for the use of these waveguides in sensing applications. Published by Optica Publishing Group.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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