Micro- and sub-nanosecond lifetime measurements using a UV light-emitting diode

The authors describe the use of an ultraviolet light-emitting diode (UV LED ), Nichia NSHU590E, as a 373 nm excitation light source for fluorescence li fetime measurements. A frequency-domain technique has been chosen to demons trate that the UV LED can be efficiently intensity modulated by driving the radio-frequency signal over a range of modulation frequencies from 10 kHz up to 330 MHz. Time-resolved measurements have been performed by using a fl uorophore with a very long lifetime of 10.2 mu s and fluorophore with a ver y short lifetime of 0.15 ns. Application of LEDs for lifetime-based chemica l sensing is discussed.