Enhanced fluorescence emission using a programmable, reconfigurable LED-array based light source

An array of up to 5 LEDs is presented to optimize the excitation signal that is transferred into a fluorescence analysis system. The array is varied by both type and drive current in order to broadly and narrowly tune the aggregate spectrum generated by the LED array to more closely match the desired excitation spectrum. Optimization results are shown for (a) a theoretical desired spectrum that clearly shows the increased flexibility of the LED array; (b) an experiment with AM1 bacteria demonstrating comparable emission output between a conventional Xenon lamp and an over driven LED array; and (c) an experiment with Rhodamine G that shows over a two-fold improvement in signal to noise ratio (or emission) obtainable using an optimized array over a non-optimized array. The flexibility of the LED array offers up to 3.2 million possibilities for aggregate spectra; without overdrive conditions, the 5-element array can only be configured into a maximum of 1020 different aggregate spectra.