A Silicon Photonic Integrated Circuit (PIC) Transceiver Design: Project Report

This work presents design of a silicon photonics transceiver that relies on AIM Photonics PDKs. Synopsys OptoCompiler was used for photonic integrated circuit (PIC) layout and Design Rule Check (DRC). The unbalanced Mach-Zehnder Interferometer (MZI) transceiver layout was simulated, laid out for fabrication, and checked for errors.Mechanical Engineerin

Optical fibre-tip probes for SERS: numerical study for design considerations.

Enhancement of sub-wavelength optical fields using sub-micron plasmonic probes has found many applications in chemical, material, biological and medical sciences. The enhancement is via localised surface-plasmon resonance (LSPR) which enables the highly sensitive vibrational-spectroscopy technique of surface-enhanced Raman scattering (SERS). Combining SERS with optical fibres can allow the monitoring of biochemical reactions in situ with high resolution. Here, we study the electromagnetic-field enhancement of a tapered optical fibre-tip coated with gold nanoparticles (AuNPs) using finite-element simulations. We investigate the electric-field enhancement associated with metallic NPs and study the effect of parameters such as tip-aperture radius, cone angle, nanoparticle size and gaps between them. Our study provides an understanding of the design and application of metal-nanoparticle-coated optical-fibre-tip probes for SERS. The approach of using fibre-coupled delivery adds flexibility and simplifies the system requirements in SERS, making it suitable for cellular imaging and mapping bio-interfaces.Trinity College, Cambridge for a PhD studentship Darwin College, Cambridge for a Henslow Research Fellowshi

Development of a low-cost Arduino-based potentiostat

A simple Arduino-based potentiostat has been developed. This potentiostat design is cost effective for low budget applications and educational purposes. The resolution and linear response of the developed potentiosat was evaluated. A cyclic voltammetry of potassium ferricyanide K3[Fe(CN)6] was performed to compare the potentiostat electrochemical performance with a commercial one. To show the portable potentiostat capabilities, cyclic voltammograms were also performed at different scan rates. Finally, the diffusion coefficient of potassium ferricyanide was calculated in a solution containing a known concentration of the salt using the Randles-Sevcik equationMechanical Engineerin

Cerebral Microdialysate Metabolite Monitoring using Mid-infrared Spectroscopy.

Funder: Wellcome TrustThe brains of patients suffering from traumatic brain-injury (TBI) undergo dynamic chemical changes in the days following the initial trauma. Accurate and timely monitoring of these changes is of paramount importance for improved patient outcome. Conventional brain-chemistry monitoring is performed off-line by collecting and manually transferring microdialysis samples to an enzymatic colorimetric bedside analyzer every hour, which detects and quantifies the molecules of interest. However, off-line, hourly monitoring means that any subhourly neurochemical changes, which may be detrimental to patients, go unseen and thus untreated. Mid-infrared (mid-IR) spectroscopy allows rapid, reagent-free, molecular fingerprinting of liquid samples, and can be easily integrated with microfluidics. We used mid-IR transmission spectroscopy to analyze glucose, lactate, and pyruvate, three relevant brain metabolites, in the extracellular brain fluid of two TBI patients, sampled via microdialysis. Detection limits of 0.5, 0.2, and 0.1 mM were achieved for pure glucose, lactate, and pyruvate, respectively, in perfusion fluid using an external cavity-quantum cascade laser (EC-QCL) system with an integrated transmission flow-cell. Microdialysates were collected hourly, then pooled (3-4 h), and measured consecutively using the standard ISCUSflex analyzer and the EC-QCL system. There was a strong correlation between the compound concentrations obtained using the conventional bedside analyzer and the acquired mid-IR absorbance spectra, where a partial-least-squares regression model was implemented to compute concentrations. This study demonstrates the potential utility of mid-IR spectroscopy for continuous, automated, reagent-free, and online monitoring of the dynamic chemical changes in TBI patients, allowing a more timely response to adverse brain metabolism and consequently improving patient outcomes

Development of an open technology sensor suite for assisted living: a student-led research project.

Many countries have a rapidly ageing population, placing strain on health services and creating a growing market for assistive technology for older people. We have, through a student-led, 12-week project for 10 students from a variety of science and engineering backgrounds, developed an integrated sensor system to enable older people, or those at risk, to live independently in their own homes for longer, while providing reassurance for their family and carers. We provide details on the design procedure and performance of our sensor system and the management and execution of a short-term, student-led research project. Detailed information on the design and use of our devices, including a door sensor, power monitor, fall detector, general in-house sensor unit and easy-to-use location-aware communications device, is given, with our open designs being contrasted with closed proprietary systems. A case study is presented for the use of our devices in a real-world context, along with a comparison with commercially available systems. We discuss how the system could lead to improvements in the quality of life of older users and increase the effectiveness of their associated care network. We reflect on how recent developments in open source technology and rapid prototyping increase the scope and potential for the development of powerful sensor systems and, finally, conclude with a student perspective on this team effort and highlight learning outcomes, arguing that open technologies will revolutionize the way in which technology will be deployed in academic research in the future.This is the final version of the article. It first appeared from Royal Society Publishing via http://dx.doi.org/10.1098/rsfs.2016.001

DIY Affordable, Low-Resolution Stylus Profilometer

Mechanical Engineering Department Senior Design ProjectA profilometer is a device that moves across the surface of a material sample and outputs the surface’s roughness value or as a two-dimensional topography plot. Throughout the course of the semester, the team built a functioning prototype of a stylus profilometer while remaining significantly under the required budget. In addition to assembling a working prototype, the team created the design files for all custom 3D printed pieces, made a bill of materials complete with a list of suppliers for each component, and wrote an assembly manual with guiding images to build the profilometer. For the electrical aspect of this project, the team has supplied circuit wiring diagrams and detailed Arduino and Python code files to run the profilometer. The designs of this do-it-yourself (DIY) prototype are open source. It is easy to build and assemble by any person with limited technical experience or resources.Mechanical Engineerin

Optical fibre-tip probes for SERS: numerical study for design considerations.

Enhancement of sub-wavelength optical fields using sub-micron plasmonic probes has found many applications in chemical, material, biological and medical sciences. The enhancement is via localised surface-plasmon resonance (LSPR) which enables the highly sensitive vibrational-spectroscopy technique of surface-enhanced Raman scattering (SERS). Combining SERS with optical fibres can allow the monitoring of biochemical reactions in situ with high resolution. Here, we study the electromagnetic-field enhancement of a tapered optical fibre-tip coated with gold nanoparticles (AuNPs) using finite-element simulations. We investigate the electric-field enhancement associated with metallic NPs and study the effect of parameters such as tip-aperture radius, cone angle, nanoparticle size and gaps between them. Our study provides an understanding of the design and application of metal-nanoparticle-coated optical-fibre-tip probes for SERS. The approach of using fibre-coupled delivery adds flexibility and simplifies the system requirements in SERS, making it suitable for cellular imaging and mapping bio-interfaces.Trinity College, Cambridge for a PhD studentship Darwin College, Cambridge for a Henslow Research Fellowshi

Measurement of electric and magnetic radiation from an electric toothbrush

Non-ionizing radiation is all around us, emitted from cell phones, TVs, computers, and microwave ovens. The aim of this work was to measure the radiation emitted from electric toothbrushes during operation, and to compare it to common devices in a house. It was found that the six electric toothbrushes of the same brand measured, emit relatively high magnetic fields of 370 mG. This is significantly higher than the magnetic field measured two inches away from the microwave. Further work should be done on measuring other types of electric toothbrushes to gain more information of possible exposure to magnetic radiation. This work highlights the possibility of potential health risks from electric toothbrushes and includes a recommendation for providing warning of high magnetic fields to consumers.Texas Materials Institut