Visit by Dr. Sapienza

The University of Kent OSA Student Chapter was proud to host Dr. Riccardo Sapienza from King’s College London on the occasion of the School of Physical Sciences colloquium.

Dr. Sapienza was welcomed at the Ingram Building by members of the University of Kent OSA Student Chapter and was taken on a short tour of the Photonics laboratories of the Applied Optics Group. Research in optical coherence tomography and photoacoustic microscopy have been shown. Afterwards Dr. Chao Wang explained research activities done at Microwave Photonics lab from the School of EDA (Engineering and Digital Arts). Research includes Ultrafast imaging systems, optical beamforming and 5G communication. Ultrafast imaging systems are used for high speed signal or image detection and can be used in microscopy and tomography applications with compressive sensing techniques solving needle in haystack problem. Optical beamforming technique is wireless optical communication using optical grating.

After the lab tours Dr. Sapienza was taken to lunch by our academic supervisor Prof. Adrian Podoleanu and joined by the chapters’ president, vice-president and secretary.

At 2 pm, Dr. Sapienza gave his talk entitled “Nanoscale photonic network lasers”. He began by giving a background of complex optical networks and the research he has conducted towards generating such network using polyester fibres combined with quantum dots to enable information flow over several micrometres. Afterwards he explained on how to use such complex network to produce a “random” laser using a specific emitter in a network and pumping the whole network and measuring the outputs of the laser.

At the end of the one hour talk, pictures were taken with the audience and with members of the chapter. The event was attended by staff and students of the Applied Optics Group, School of Physical Sciences and the Communications Research Group, School of Engineering and Digital Arts.

 

Abstract of the talk:

With decades of proven success, lasers have become central to many technologies that are used in manufacturing, communications, medicine and entertainment. Yet laser research continues to develop new types of light sources with unique and unprecedented characteristics, that have not yet been realised with existing laser technology.

Conventional lasers are generally restricted to aligned mirrors at fixed positions and 1D geometries, resembling the original design from the ‘60s. Instead, random lasers are mirror-less lasing systems which use highly disordered materials to obtain laser action, and have attracted significant interest due to their structural simplicity. Here the disordered matrix folds the optical paths by multiple scattering, while optical gain provides the amplification that triggers lasing. The result is an opaque medium in which laser light is generated by flowing and scattering in a speckle-like pattern.

I will introduce photonic network lasing originated from a web-like network of subwavelength waveguides. Building on this I will show how we design and fabricate biocompatible random laser lasers that can be use as sensitive sensors for living tissue integration, opening a path between complex photonics and medicine for future health care.

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