Ablation device and method for subsurface biological tissue ablation

The present invention relates to a subsurface laser-induced optical breakdown (LIOB) ablation system including an optical source for providing optical pulses and an optical waveguide for guiding the optical pulses to a subsurface target biological tissue site. The system is characterised in that it further includes a pulse shaping system configured to modify a temporal profile or a wavefront profile of an optical pulse provided by the optical source to compensate for temporal or spatial modifications imposed on the optical pulse during the passage of the optical pulse to the subsurface target biological tissue site, and configured to provide the compensated optical pulse to the optical waveguide for guidance to the subsurface target biological tissue site. The present invention also relates to a catheter and a subsurface laser-induced optical breakdown (LIOB) ablation method.

Microfluidic Droplet-Based Liquid–Liquid Extraction and On-Chip IR Spectroscopy Detection of Cocaine in Human Saliva

Yu-Chi Chang, Nico de Rooij, Hans Peter Herzig, Lubos Hvozdara, Philip Wägli

We present a portable microsystem to quantitatively detect cocaine in human saliva. In this system, we combine a microfluidic-based multiphase liquid-liquid extraction method to transfer cocaine continuously from IR-light-absorbing saliva to an IR-transparent solvent (tetrachloroethylene) with waveguide IR spectroscopy (QC-laser, waveguide, detector) to detect the cocaine on-chip. For the fabrication of the low-cost polymer microfluidic chips a simple rapid prototyping technique based on Scotch-tape masters was further developed and applied. To perform the droplet-based liquid-liquid extraction, we designed and integrated a simple and robust droplet generation method based on the capillary focusing effect within the device. Compared to well-characterized and commonly used microfluidic H-filters, our system showed at least two times higher extraction efficiencies with potential for further improvements. The current liquid-liquid extraction method alone can efficiently extract cocaine and pre-concentrate the analytes in a new solvent. Our fully integrated optofluidic system successfully detected cocaine in real saliva samples spiked with the drug (500 mu g/mL) and allowed real time measurements, which makes this approach suitable for point-of-care applications.

Amer Chemical Soc2013

Proof of principle demonstration of a self-tracking concentrator

Christophe Moser, Eric Tremblay, Volker Günter Zagolla

We present to the best of our knowledge the first successful demonstration of a planar, self-tracking solar concentrator system capable of a 2-dimensional angular acceptance of over 40 degrees. The light responsive mechanism allows for efficient waveguide coupling and light concentration independently of the angle of incidence within the angular range. A coupling feature is created at the focal spot of the optical system by locally melting a phase change material which acts as an actuator due to the large thermal expansion. A dichroic prism membrane reflects the visible light so that it is efficiently coupled into a waveguide at the point of the created coupling feature. We show simulation results for concentration and efficiency, validated by an experimental proof of concept demonstration of a self-tracking concentrator array element. Simulations show that a system based on this approach can achieve 150X effective concentration by scaling the system collecting area to reasonable dimensions (40 x 10 cm(2)). (c) 2014 Optical Society of America

Optical Society of America2014

Self-tracking Solar Concentration

Volker Günter Zagolla

Solar concentration is intended to decrease the cost of expensive solar cell material by replacing the solar cell with a focusing optical system as the initial receiving aperture. This reduces the amount of solar cell material needed but adds the need of tracking to the entire system in order to keep the smaller solar cell at the focal spot. In state of the art concentrators, precise tracking (less than 1°) is needed in two directions to cover diurnal and seasonal variations. This adds to the cost of the system, diminishing the savings from the smaller solar cell, and consumes energy which in turn decreases the overall system efficiency. A self-tracking concentrator has the potential to increases the tolerances of the system (less precise tracking needed) and cover seasonal variations (only tracking in one dimension remains). Self-tracking makes use of the energy of the spectrum that is typically not utilized in PV, thus self-tracking does not consume an outside surplus of energy. During the thesis such a self-tracking system was developed. This thesis describes two concepts for the realization of a self-tracking concentrator, one of which is then developed into a working demonstration device with an angular acceptance of 32° (±16°). The work covers both the development of these two different mechanisms as well as an analysis of their performance as a single element and a discussion of their performance as part of a much larger device. The first concept, the micro-fluidic concentrator, uses vapor bubbles to efficiently couple light into a liquid waveguide (chapter 3), while the second concept, based on a phase change actuation uses the thermal expansion of paraffin wax to create a coupling feature at a waveguide (chapter 4). Based on the findings, the phase-change concentrator was then expanded into a self-tracking concentrator with a possible effective concentration of 10x (chapter 5). As a result this thesis shows the feasibility of a self-tracking concentrator and describes in detail the processes and techniques for its realization. Future work based on the designs presented in this thesis can optimize the concepts. Simulations show that a system based on this approach can achieve 150x effective concentration by scaling the system collecting area to reasonable dimensions (30 x 1 cm²). An optimized optical system can then also increase the acceptance angle of the self-tracking concentrator to the ±23° needed in order to cover seasonal variations. In addition, the presented concept is based on earth abundant, inexpensive materials, making it technologically and economically viable to extend it to much larger formats.

EPFL2015

Self-tracking Solar Concentration

Volker Günter Zagolla

EPFL2015