Performance Evaluation of Ultraviolet Light Emitting Diodes as an Excitation Source in Fluorescence Measurement of Plant Leaves

Abstract

This work reports the performance of ultraviolet light emitting diodes (UV-LEDs) that have been actively developed in recent years. We examined whether the UV-LEDs become a new excitation source instead of the conventional UV-laser in fluorescence measurement of plant leaves. Some UV-LEDs provided sufficient irradiance and two dimensional distributions for the excitation. However, weak visible emission (400nm-600nm) existed besides main peak emission in ultraviolet region. Then, the fluorescence measurements were carried out by sbsorbing the visible emission from UV-LEDs with a UV transmitting filter (UV-D35).In addition, output level and peak spectrum of each UV-LED changed according to operative temperature. It has been understood that the temperature control of UV-LEDs is necessary. From the overall evaluation, it is concluded that the UV-LEDs can be used for an excitation source in the fluorescence measurement of plant leaves.