A PULSED LASER SYSTEM FOR THE STUDY OF MICRO-SECOND DELAYED FLUORESCENCE FROM PLANTS

Abstract—A new laser system is designed for the investigation of S delayed fluorescence. This is intended to overcome some undesirable features present in other current designs, such as low actinic light fluxes and long illumination times, or slow responses owing to long turn-off times of the stimulation source and the presence of fluorescence artifacts.
The system uses a pulsed argon-ion laser and bears little resemblance to either the modified Becquerel phosphoroscope used by Lavorel (1971) or to those systems requiring shutters. Cheapness of design together with the ability to adjust such parameters as pulse duration easily, make this design attractive to most laboratories in which short (10 μs) high intensity (10⁵ W m^-2) pulses with rapid (1.5 μs) turn-off times and high on-to-off contrast ratios (10⁶:1) are required.
Certain design criteria are strictly imposed in order to produce kinetic data that can be meaningfully analysed.