A method of analyzing a plurality of biological sample volumes comprises emitting, along an excitation optical path toward a sample holder holding the plurality of biological sample volumes, electromagnetic radiation from a broadband LED, wherein the broadband LED emits the electromagnetic radiation across a range of wavelengths at a total output power of at least 5 watts and at a maximum intensity at a wavelength less than 600 nanometers and at an intensity less than 30 percent of the maximum intensity at a wavelength of 650 or 670 nanometers, and receiving, by a sensor, an electromagnetic emission transmitted from the sample holder along an emission optical path.