Single optical fiber probe for fluorescence detection and optogenetic stimulation.
We have developed a fiber-optic-based probe for precise delivery of stimulation/excitation light pulses and detection of faint fluorescence signals for applications in neuroscience and optogenetics. In this design, a thin multimode fiber serves as the head of the probe to be inserted into the brain. This fiber is used to deliver light to the region of interest and guide a sample of the emission signal back to detectors. The major tradeoff in the design of such a system is to decrease the size of the fiber and intensity of input light to minimize physical damage and to avoid photobleaching/phototoxicity but to keep the signal-to-noise ratio (S/N) reasonably high. Here, the excitation light and the associated emission signal are frequency modulated. Then, the output of the detector is passed through a time lens which compresses the distributed energy of the emission signal and maximizes the instantaneous S/N. By measuring the statistics of the noise, the structure of the time lens is designed to achieve the global optimum of S/N. We have also designed side-firing fibers and a micromechanical assembly for distributed light delivery and fluorescence detection.
Department of Electrical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA. pashaie@uwm.edu
Ramin
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Pashaie
Ryan
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Falk
D000818:Animals; D001923:Brain Chemistry; D002478:Cells, Cultured; D003198:Computer Simulation; D005336:Fiber Optic Technology / Q000295:instrumentation*; D005456:Fluorescent Dyes / Q000737:chemistry; D006624:Hippocampus / Q000166:cytology; D008954:Models, Biological; D055100:Optical Fibers; D062308:Optogenetics / Q000295:instrumentation*; D051381:Rats; D017207:Rats, Sprague-Dawley; D059629:Signal-To-Noise Ratio; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*
D005456:Fluorescent Dyes