Investigations on the Use of Laser Dyes as Quantum Counters for Obtaining Corrected Fluorescence Spectra in the Near Infrared
SourceSeveral laser dyes were evaluated as quantum counters for obtaining corrected fluorescence spectra in the near infrared regions. Preliminary results indicate that hexamethylindotricarbocyanine (HITC) and LDS-798 (Exciton Chemical Co., Overlook, OH) both have quantum yields that are independent of wavelength and can extend the limits of spectral correction to 800 and 700 nm, respectively. A binary quantum counter containing a mixture of Rhodamine B (RhB) and HITC was also evaluated. The quantum yields of HITC and LDS-798 were estimated to be 0.28 and 0.14, respectively, compared to a value of 0.95 attributed to RhB. Examples of corrected spectra obtained using LDS-798 and HITC are compared with absorbance spectra and other accepted standards. Preliminary stability tests are discussed and further studies suggested.