Research chemist, U.S. Secret Service, Technical Security Division, TD&PB, N.W. Washington, DC
FBI Forensic Science Research and Training Center, Quantico, VA
(Received 17 July 1987; accepted 24 August 1987)
The fluorescence spectra of several components having fluorescence in the vis-near infrared (IR) region were obtained. Several of these components were obtained from IR luminescent inks. The spectral features (excitation and emission spectra and their intensities) explain the observed emission when these components are analyzed with an IR luminescence apparatus (excitation with blue green light/emission detected with IR sensitive television (TV) tube) or a laser induced fluoresence system (514.5-nm excitation with argon ion laser/emission detected with laser light absorbing goggles or with IR sensitive TV tube). The emissions from these methods are part of the same fluoresence emission peak. The emission response for each of the methods is dependent on the division of this peak between the vis and near IR region and its intensity in these regions. The intensity is dependent on the excitation source.
Paper ID: JFS12473J