Supervisors: Dr Tomas Cizmar and Prof Sir Alfred Cuschieri
Flexible endoscopes allow for minimally invasive imaging of otherwise optically inaccessible objects, making them valuable tools particularly in the context of Bio-Medical Science. The standard technology utilises bundles of optical fibres to convey the image, each of them corresponding to a single pixel of the image transmitted. In many cases however, the instrument footprint (usually in excess of a few millimetres) is far too large to allow for its usage within sensitive tissue without causing damage or altering its function. Many efforts have therefore been aiming at reducing the endoscopic probe size .
Recent advances in holographic imaging using multimode fibres have made possible to reduce the endoscope probe down to a single optical fibre [2,3]. Figure 1 illustrates the improvement in lateral dimensions of a single fibre compared to a conventional fibre-optic endoscope. These techniques allow compensating the modal dispersion in the fibre, thus enabling aberration-free imaging through a single multimode fibre, whereby the imaging resolution is limited by diffraction by the numerical aperture of the optical fibre. Such approaches typically involve pre-shaping of the incident wavefront at the proximal end of the fibre by means of digitally-controlled diffractive optical element, usually a spatial light modulator (SLM), to produce a desired intensity light distribution at the distal fibre facet. The ability to control the spatial light output from the fibre can be used in particular to produce and dynamically control a sharp focus at some distance from the facet, which forms the basis for scanning-point imaging [2,3] and optical micromanipulation .
This project aims at further developing fibre-based imaging technology to achieve resolution down to hundreds of nanometres, as well as optical manipulation through single-fibre endoscopes. This entails exploring new imaging and trapping configurations using specialty optical fibres with very high numerical aperture.
-  B.A. Flusberg, E.D. Cocker, W. Piyawattanametha, J.C. Jung, E.L.M. Cheung, and M.J. Schnitzer, “Fiber-optic fluorescent based imaging,” Nature Methods 2, 941-950 (2005).
-  T. Čižmár and K. Dholakia, “Exploiting multimode waveguides for pure fibre-based imaging,” Nature Communications 3, 1027 (2012).
-  M. Plöschner, T. Tyc, and T. Čižmár, “Seeing through chaos in multimode fibres,” Nature Photonics 9, 529-535 (2015).
-  T. Čižmár and K. Dholakia, “Shaping the light transmission through a multimode optical fibre: complex transformation analysis and applications in biophotonics,” Optics Express 19(20), 18771-18884 (2011).
Journal and Conference Papers and Posters
[November 2017] 3-D holographic optical manipulation through high-NA soft-glass multimode fibre, Ivo Leite, Sergey Turtaev, Xin Jiang, Alfred Cuschiere, Philip St.J. Russell and Tomas Cizmer. Nature Photonics, published online 04/12/2017; should appear in print January 2018 (2017).
[November 2017] Comparison of nematic liquid-crystal and DMD-based spatial light modulation in complex photonics, Sergey Turtaev, Ivo T. Leite, Kevin J. Mitchell, Miles J. Padgett, David B. Phillips and Tomas Cizmar. Optics Express Vol. 25, pp. 29874-29884.
[January 2017) Novel single-fibre probes for advanced biophotonic applications, Ivo Leite, Sergey Turtaev, Xin Jiang, Philip St. J. Russel and Thomas Cizmer. Poster presented at SPIE BiOS, Adaptive Optics and Wavefront Control for Biological Systems III, San Francisco, USA, 30th January 2017.
[January 2017] High-speed wavefront modulation in complex media, Sergey Turtaev, Ivo Leite and Tomas Cizmar. Paper presented at SPIE BiOS, Adaptive Optics and Wavefront Control for Biological Systems III, San Francisco, USA, 30th January 2017.
[August 2016] Accelerating wavefront shaping in complex environment. Oral presentation at the Biophotonic approaches: From molecules to living systems conference, Dundee, Scotland, 23rd August 2016.
[August 2016] Advanced biophotonics down a single fibre. Oral presentation at the Biophotonic approaches: From molecules to living systems conference, Dundee, Scotland, 22nd August 2016.
[May 2016] Holographic optical tweezing via a multimode fibre by I. Leite, S. Turtaev, Xin Jiang, Philip St. J. Russell, and Tomas Cizmar. Poster presented at SUPA 2016 Annual Gathering, Glasgow, Scotland.
[May 2016] High-resolution holographic micro-endoscopy and manipulation by I. Leite, S. Turtaev, Alfred Cuschieri, and Tomás Čižmár. Poster presented at Highland Spring School on Mesoscopic Physics, Trest, Czech Republic.
[December 2015] Multimode fibres for micro-endoscopy, Turtaev, Sergey / Leite, Ivo T. / Čižmár, Tomáš. Optofluidics, Microfluidics and Nanofluidics. Volume 2, Issue 1, Pages 31–35. [OPEN ACCESS]
[June 2015] Optical Pump – Terahertz Probe Carrier Lifetime Measurement in InAs/GaAs Quantum Dots Based Photoconductive Antennae by A. Gorodetsky, Ivo Leite, N. Bazieva and E.U. Rafailov. Paper presented at CLEO®/Europe-EQEC 2015, Munich, Germany.
[June 2015] Towards High-intensity Terahertz Generation: InAs/GaAs Quantum Dots Based Antennae Optically Pumped Up To 1W by Ivo Leite, A. Gorodetsky, R. Leyman, N. Bazieva and E. Rafailov. Paper presented at CLEO®/Europe-EQEC 2015, Munich, Germany.
[April 2015] Studying carrier lifetime in InAs/GaAs quantum dot devices by optical pump–terahertz probe measurements. Poster presented at the 8th Terahertz Days Conference, Arêches-Beaufort, France.