Prof. Xiaoyi Bao University of Ottawa, Canada [bio]
"The non-uniformity and dispersion in SBS based fibre sensors"
For a fibre with complex index profile, its density fluctuations change with position and it also introduces birefringence, hence the Brillouin frequency changes with position due to variation of modal index, and sound velocity has a range instead of being a constant. As a result, the single mode fibres support multiple Brillouin resonances varying in position, even with polarization scramblers (PS) of the pump and probe waves. For a Brillouin optical time domain analysis (BOTDA), at a specific location, because of the spatial resolution, the measured Brillouin frequency still gives a range, although PS can help to reduce this fluctuation, as the spatial resolution is much smaller than the beat length of single mode fibre (SMF). The measured Brillouin frequency variations in one position and its location dependence reflect the non-uniformity of the optical fibre, rather than the systematic error of the sensor detection system. When a fibre supports elliptical birefringence, then four Brillouin resonances can be found for an acoustically uniform fibre based on theoretical calculation of their eigenmodes.
Prof. Alan K.T. Lau
"The potential of embedded sensor technologies in NASA's aerospace applications"
In order to mitigate structural failures and therefore the catastrophic failures to aerospace structures, NASA has been at the forefront developing of real-time on-board monitoring capabilities using a large range of advanced sensors. Optical sensors have taken a significant share in the context of structural health monitoring system. Further, advanced optical sensor systems have great potential in NASA’s effort of developing smart structures for orbital vehicles and other space hardware. This talk will critically discuss the use of optical sensors in NASA’s space and aircraft applications.
Winthrop Prof. David Sampson University of Western Australia, Australia [bio]
"Human cancer imaging with optical coherence tomography microscope-in-a-needle technology"High-resolution optical imaging at the cellular level is a cornerstone of modern biology and medicine. It represents the gold standard in much medical diagnosis, which is conducted on collected specimens that have been carefully prepared for histological imaging. Such high resolution remains an elusive goal for medical imaging of living humans. Only optics has so far achieved such resolution in the living human, but only at very superficial depths in tissues – from the surface to a few millimetres at most. Endoscope and catheter technology has enabled optics to access hollow organ systems in the body, but general access to solid tissues has not been available. We have been working on microscope-in-a-needle technology to provide such access whilst retaining high resolution. Our work has mainly been based on optical coherence tomography, and has focussed on miniaturisation to avoid unacceptable levels of tissue damage and three-dimensional imaging. In this talk, I will describe our microscope-in-a-needle technology, including ongoing attempts to image human breast cancer during surgery.