Fluorescence studies of carbocyanines using AOTF

Over the past few years acceptance of acousto-optic devices which can control optical radiation has increased. In this paper the use an acousto-optic tunable filter (AOTF) within an existing spectrofluorometer as a replacement for the excitation monochromator is reported. Long wavelength absorbing carbocyanine dyes that have strong absorption and high quantum yield are used as standards. The major advantage of using an AOTF filter is the wavelength purity and that it can act as a wavelength selector in place of a monochromator. The use of AOTF in place of bandpass filters for removing laser diode side bands is also discussed.