Nanophotonics is the interaction of light with structures on the order of, or smaller than the wavelength of light. At these length scales optical structures can be engineered to manipulate light: to diffract it, scatter it, concentrate it and even to bend it. Recent advances in large scale fabrication of optical nanostructure arrays, for example nanoimprint lithography and holographic techniques, have meant that nanophotonics has found many new applications: from improving the sensitivity and selectivity of sensors and photodetectors, to increasing the efficiency of light harvesting for photovoltaics.
For research purposes rapid prototyping of different geometries is highly desirable. The standard way of fabricating nanophotonic structures in the lab is by electron beam lithography: writing patterns in a special resist with a focused beam of electrons. Electron beam lithography (EBL) allows the flexibility to design and realise a wide range of nanostructures, but there is a catch: it is very slow. For the types of patterns used in many optoelectronic applications, we are typically limited to array sizes of a few 10s to 100s microns square. These size restrictions make it challenging to optically characterise EBL fabricated structures.
The goal of this project is to design, build and test an optical set up to measure the reflection and transmission of small area, i.e. a few 10s – 100s of microns square, nano-patterened areas. This set-up will be a critical component of the new Nano-photonics Characterisation Lab in room E135 of the Engineering building, being set up by Dr Tom White and Dr Fiona Beck as part of their research on nanostructured optoelectronics.
1. Design and build an optical setup based on standard optical breadboard components. The goal will be to focus light from a source on to a sample, and to collect the reflected and transmitted light in the fibre aperture of a spectrometer. This will involve the positioning and alignment of mirrors, beam-splitters, fibre couplers and an objective.
2. Evaluate the operation of the micro-optical set up compared with to a standard large area spectrophotometer in the wavelength range of interest and fully document the specifications and limitations.
3. Produce documentation and procedures to allow the continuing maintenance and operation of the set-up after the project is complete. Provide training in the operation of the system for users.
This is a ‘hands-on’, practical project, suitable for students with an interest in nanophotonics, optics, optical devices and optoelectronics. It would be particularly good experience for anyone interested in an academic career, or R&D in the area of optical characterisation. Some knowledge or experience with optical components would be useful, but is not essential: more importantly, a certain amount of meticulousness (i.e. the ability to pay attention to detail) and persistence will be required. The ability to think logically and creatively solve problems will be necessary.
Prerequisite: Basic understanding of optics is essential. ENGN3512 (Optical Physics) would be useful.
Info on microscopes and Koehler illumination to be provided:
This is the chance to help build a research grade optical set up from scratch, take it through the testing and verification phase, all the way to documentation and hand over. Over the course of the project you will:
- Design, build and align optical systems
- Gain knowledge of different optical components, their operation and limitations
- Learn about optical characterisation
- Get a chance to independently and creatively solve problems
- Project manage
- Gain practical experience in technical documentation
- Undertake independent research and build up your analytical skills
- Be able to walk away knowing that something you built is being used by researchers
Optic, Nanophotonics, Optoelectronics, Optical Devices, Characterisation, Photovoltaics