DEVELOPMENT OF AN ACOUSTO-OPTIC TUNABLE FILTER BASED TIME-DOMAIN FLUORESCENCE SPECTROMETER WITH HIGH SCANNING SPEED AND HIGH THROUGHPUT FOR OPTICAL BIOPSY APPLICATIONS

Abstract

<p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 10.0px Times; color: #343434} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 10.0px Times; color: #4c4c4c} span.s1 {font: 10.5px Times} span.s2 {color: #4c4c4c} span.s3 {color: #343434} span.s4 {color: #7a7a7a} span.s5 {color: #676767} span.s6 {color: #030303}</p> <p>In this project, we have developed an acousto-optic tunable filter (AOTF) -based timeresolved fluorescence spectroscopy (AOTF-TRFS) apparatus capable of acquiring fluorescence spectra and lifetimes of biological fluorescent probes with high data acquisition speed required for real-time clinical diagnostics. The system incorporates a non-collinear TeO₂ AOTF, a gated multichannel plate photomultiplier tube (MCP-PMT), a picosecond Nd:YAG pulsed laser, a digital oscilloscope with high sampling rate and a bifurcated fiber optic probe for light delivery and collection. Typically low throughput of the AOTF was enhanced by collecting both first order diffraction beams. The system performance was evaluated by measuring the fluorescence of 9-CA, fluorescein, NADH and FAD. The emission peaks in time-integrated spectra and the retrieved decay lifetimes were in good agreement with literature values over the desired spectral region between 370 nm and 550 nm. The system was able to collect a set of time-resolved fluorescence decay data for a single point site across a 200 nm wavelength range at 5 run increments within 4 s, which is a significant improvement over the previous generation gratingbased instrument.</p>