(Sub)-Picosecond Spectral Evolution of Fluorescence Studied with a Synchroscan Streak-Camera System and Target Analysis

Abstract

A synchroscan streak camera in combination with a spectrograph can simultaneously record temporal dynam- ics and wavelength of fl uorescence representable as an image with time and wavelength along the axes. The instrument response width is about 1% of the time range (of typically 200 ps to 2 ns). The spectral window of 250 nm may lie between 250 and 850 nm. Such spectrotemporal measurements using low excitation intensities have become routine. Sophisticated data analysis methods are mandatory to extract meaningful physicochemical parameters from the wealth of information contained in the streak image. In target analysis a kinetic scheme is used in combination with assumptions on the spectra of the species to describe the system. In this chapter the principals of operation of a streak-camera setup are described, along with the fundamental and technical limitations that one encounters. The correction and calibration steps that are needed as well as data processing and analysis are discussed. Several case studies of bioluminescence are presented, with a particularly in-depth analysis of trimeric Photosystem I core particles of the cyanobacterium Spirulina platensis.