Specifications

Luminescence Decay Measurement in the Microsecond Range 23

Fig. 29: Trace parameters and display parameters recommended for fluorescence decay measurement

Fig. 30: Decay curves recorded with the setup parameters shown in Fig. 27 through Fig. 29

Luminescence Decay Measurement in the Microsecond Range

A suitable setup for luminescence decay measurements in the µs range is shown in Fig. 31.

For extremely long decay times the laser pulse repetition rate must be reduced to a few 10 kHz

or less. Using ps pulses at a repetition rate this low would result in an extremely low average

excitation power. It is therefore better to use excitation pulses with a duration of a few 100 ns

to several µs. The bh BDL-SMC diode laser is therefore operated in the CW mode [5]. The

laser is switched on and off periodically via its on/off input. To generate pulses of appropriate

duration suitable on/off signal is generated by a bh DDG-200 pulse generator module. The

pulse width and repetition rate of the excitation pulses is defined by the DDG-200 setup pa-

rameters.

SYNC

Trigger Out

+12V

Detector

DPC-230 module

PMC Power supply and

DCC-100 Detector Controller

bh PMC-100

Photon

ps Diode laser

A-PPI-D Pulse

Overload Shutdown

Filter

Sample

Laser Switch Box

bh BDL-SMC

Inverter

Delay

DDG-200 Pulse Generator

Module

or other pulse generator

Power

on/off

A-PPI-D

pulse

inverter

Fig. 31: Luminescence decay measurement in the microsecond range