Student Projects

Below are listed some of the student projects offered by the Fiber sensors and Supercontinuum group. All projects can be tailored to be either a special course, a B.Sc., or a M.Sc. project.
Optical coherence tomography: In-depth visualization of skin to diagnose skin cancer
  • Optical coherence tomography (OCT) is a broadband interferometric technique to image refractive index contrasts from a scattering media in a sample. The strength in this method is that one can achieve few-micron resolution, earlier only possible with confocal microscopy, but also image in depth being the attractive feature of ultra-sound scanning which on the other hand has poor resolution (100 microns at best). This makes OCT a unique tool to diagnose irregularities in the skin such as skin-cancer.

    In spectral domain (SD) OCT, interference between light from a sample scatterer and a reference beam forms a specific harmonic pattern seen in the spectrum of the mixed signal known as an interferogram. Applying a Fourier transform reveals the position of the scatterer in the space domain. However, the minimum feature one can resolve is fundamentally limited by how broad the emission spectrum of the light source is. To achieve ultra-high resolution, a supercontinuum source can be exploited as light source which defines a new theoretical limit on resolution.

    In the project, the student will work with a supercontinuum source to create OCT images in skin with high resolution as close to the theoretical limit as possible.

    In the process she/he will learn about necessary numerical processing to reach ultra-high resolution which includes spectrometer calibration and dispersion compensation being essential in order to reach state-of-the-art resolution.

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Bend enhanced non-linear fibers for supercontinuum experiments
  • Supercontinuum light sources based on optical fibers as a non-linear medium are great source of light thanks to the waveguide dispersion, strong confinement, longer interaction lengths, good beam quality, and better heat management. A supercontinuum can be generated in a fiber by pumping a powerful pump beam, however efficiency of supercontinuum depends on many factors such as non-linearity and dispersion of fiber. A smaller core diameter increases the power density, hence contributes to the non-linearity of fiber. Tapering of fiber has been a conventional approach to reduce the core diameter in order to increase non-linearity. However, tapering of fiber is quite challenging and not an easy solution.

    This project will develop novel fiber, which on being tightly coiled undergoes a dramatic reduction of effective area, hence increases in non-linearity. Candidate is likely to learn modelling of optical fibers using COMSOL and MATLAB. Candidate will work in supercontinuum lab and will have hands on experience with supercontinuum generation experiments. There is a clear plan for a publication in an international journal with a possibility of a patent.



 
Supercontinuum generation in higher order modes
  • Supercontinuum generation in higher order modes can be a great advancement in developing next generation mid-infrared supercontinuum sources. Currently, most of the mid-infrared supercontinuum sources rely on chalcogenide fibers. Unfortunately, chalcogenide fibers have longer zero dispersion wavelengths. Despite of strong waveguide dispersion, the zero dispersion wavelength is long enough to avoid the use of most developed fiber lasers as a pump source.

    However, higher order modes naturally have shorter zero dispersion. Therefore it is possible to exploit a shorter zero dispersion wavelength by launching a pump as a higher order mode. This project will work towards generation of supercontinuum light in mid-infrared region while being pumped by most mature fiber lasers available.

    Candidate will work in supercontinuum lab and will have hands on experience with supercontinuum generation experiments. There is a clear plan for a publication in an international journal.


 
Ultrafast nonlinear optics in gas-filled hollow-core fibers
  • Gases offer many attractive features as media for nonlinear optics. Unlike solid-state materials, they can handle high laser intensities and their nonlinearity and dispersion can be tuned by varying the pressure and gas mixture. They also offer wider transparency windows than their solid-state counterparts.

    This project aims to investigate light-gas interactions in the mid-IR transmission region using a novel class of optical fibers known as antiresonant fibers. The candidate will have the chance to learn how to model these fibers using numerical tools and then he/she will be involved in gas-based supercontinuum experiments. The proposed project will lead to a high profile publication followed by presentation in an international conference.


 
Liquid soft-glasses towards novel nonlinear optofluidic fibers
  • Chalcogenide glasses have existed for more than 60 years, yet they have only recently been proven as emerging materials offering new possibilities in Photonics. One of their most important properties is their high nonlinear coefficient making them suitable for nonlinear optics. Liquid chalcogenide glasses have also attracted a lot of attention recently mainly because they offer great integration flexibility while the optical properties can be tailored based on the application.

    This project involves the design of a novel nonlinear optofluidic optical fiber based on various highly nonlinear chalcogenides for supercontinuum generation. The candidate will have the chance to work in a multidisciplinary project which merges material science with optics. The proposed project will lead to a journal publication and presentation to an international conference.