[English]

Prosiectau Ffiseg ar gyfer myfyrwyr bl.3 a bl.4


Disgrifiad prosiect

Simulating periodicity in Photonic Crystals

(supervisor: Chris Finlayson)

Nature of project: software, theory

Available to students on full-time physics degree schemes or joint students.

Project description and methodology

All the laws of optics that you know start to break down when we make materials which are structured on the sub-micron size-scale of the wavelength of light, often called photonic crystals (PCs).[1] A subcategory of PCs involves the packing of mono-disperse particles into ordered arrays, by various means, with well-defined periodicity. New optical effects are then possible such as photonic bandgaps, structural colour[2], and optical switching.

In this project, the student will generate 1D, 2D and 3D optical simulation models of periodic dielectric structures, investigating the effects of crystalline geometry, index-contrast and order/disorder on the predicted reflectivity and light-field properties. In 1D, this can be initiated using a pre-existing "transfer-matrix" simulation code within the software IGOR.

A successful project will develop beyond the above in one/some of the following directions:
Implementation of the MEEP freeware programme, in order to generate and simulate 2D/3D (e.g. cubic lattices of spheroids) structures.[3] An analogue system of interest for the packing of micro-spheres into photonic crystals is the so-called "polymer opals"(POs)[4], which is widely researched in the Dept.

Due to the simulation/software based nature of this project, it should be robust to any Covid restrictions to lab access.

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

Additional scope or challenge if taken as a Year-4 project: Development of MEEP towards bandgap analysis, and the ability to use this as a predictive tool in the design of new target optical structures.

Please speak to Chris Finlayson (cef2) if you consider doing this project.

Initial literature for students:

  1. http://en.wikipedia.org/wiki/Photonic_crystal
  2. P. Vukusic and J. R. Sambles, Nature, vol. 424, p852 855 (2003)
  3. http://meep.readthedocs.io/en/latest/Introduction/
  4. C. E. Finlayson et al., Adv. Mater., vol. 23, p1540 1544 (2011)

Novelty, degree of difficulty and amount of assistance required

The project is not designed to feature any experimental component, and is therefore suitable for students interested in theory and/or computation.

Project milestones and deliverables (including timescale)

milestoneto be completed by
Familiarisation with theory and softwareChristmas
Generation of target simulationsend of February
Simulation phasemid-March
Analysis/results phaseEaster