An apparatus for providing light to molecules of a specimen in a fluorescence microscope includes a light emitting diode and an optical element including a phosphor. The molecules have a peak excitation wavelength. The LED emits light at a first wavelength; the phosphor is capable of receiving the light at the first wavelength and emitting light at a preselected second wavelength different than the first wavelength. The second wavelength is substantially similar to the peak excitation wavelength of the molecules.
