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“Thermo-mechanical interactions of short and ultrashort laser pulses at the cellular level” |
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Sept 2007 - Dec 2007 | ||
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DESCRIPTION |
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| Time-resolved measurements of a variety of phenomena are very important to understand the physics that underlies, for instance, a laser-tissue interaction. It is also important, in the same context of the physical understanding of laser-tissue interactions, the dependence of the interaction on light color. For these two purposes we developed a series of experiments and techniques to understand the physics of an interaction of a laser pulse and a transparent tissue. Amongst the variety of phenomena we can observe during such an interaction we can list: the formation of bubbles; the generation and propagation of shockwaves; and nonlinear optics effects including multi-photon ionization. All of these observations required the implementation of suitable experimental techniques that included pump-probe laser experiments, using a tunable pulse laser system (Nd:YAG laser and an optical parametric oscillator OPO); the design and implementation of piezoelectric based pressure sensors; and a sophisticated image relay system which allowed us to grab video images in real time of the event consisting in a laser pulse being delivered to the tissue sample. Our system is capable of resolving micro-sized bubbles and shockwaves, with below ns time resolution. This methods and techniques will be implemented in my home laboratory to complement and match our current research collaboration. Back in CICESE we are currently working with Dr. Sergei Stepanov, an expert on adaptive fiber based nonlinear optics interferometers. The scope of the collaboration with Dr. Stepanov is to develop a fiber based pressure sensor, to specifically measure the peak pressure that is achieved when an intense laser pulse is delivered in tissue. Adaptive interferometers are ideal for this application, since it will respond quickly enough to follow the generation of shockwaves and also we would have an all optical experimental set up for both excitation and probing of the laser-tissue interaction. Dr. Stepanov’s reputation, as one of the pioneers in experimental nonlinear optics, is internationally recognized and his contributions to the field are outstanding. Having the chance to start research collaboration with him and his group is a big plus for our current research. As a result of the intense and continuous research collaboration between Professor Aguilar’s group and my own group in CICESE, I have been successful when applying for funding at my home country. In year 2007 our proposal “Estudio de los efectos foto-inducidos en tejido biológico con láseres pulsados de nanosegundos y femtosegundos” was granted by CONACyT in the amount of ~$82,000 USD. The grant is indentified by the number 57309. From our previous collaborations and UC MEXUS support, Prof. Aguilar has also received NSF funding, which we have reported promptly. At the present time we are discussing the possibility to submit a grant proposal to NSF through the NSF International Programs. Intense and productive students exchange activity has been one of the main outcomes of the current research collaboration. The exchange has included Francisco Perez Gutierrez (PhD student at UCR) visiting our laboratory and the Optics Department in CICESE to learn optics and nonlinear optics; during his visits Francisco had taught and trained our students (in my group) on how to culture and maintain cells and tissues. UCR has hosted (our PhD student) Rodger Evans who spent two weeks at Professor Aguilar’s laboratory to help them to set up the pulse tunable laser system and a sophisticated laser micro-processing stage. Currently, our students communicate on an almost everyday basis to discuss results and to plan experiments. Also, given that Riverside and Ensenada are only 200 miles apart from each other, frequent (or on demand) visits and communication amongst the research collaboration members are not an issue. This aspect brings in lots of success to collaborations like the one depicted here. | ||||
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