Abstract
The authors describe the use of an ultraviolet light-emitting diode (UV LED), Nichia NSHU590E, as a 373 nm excitation light source for fluorescence lifetime measurements. A frequency-domain technique has been chosen to demonstrate 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 fluorophore with a very long lifetime of 10.2 μs and fluorophore with a very short lifetime of 0.15 ns. Application of LEDs for lifetime-based chemical sensing is discussed.
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