Fluorescence backgroundless Ti: Sapphire laser using acousto-optical tunable filter for Raman spectroscopic measurements

The background noise inherent to tunable lasers, which emit broad band spontaneous fluorescence from the laser-active medium, is detrimental for sensitive Raman measurement. Using the diffraction effect in an acousto-optic device, we have developed a fluorescence backgroundless Ti : sapphire laser suited for near-infrared Raman spectroscopy. A Raman excitation profile consisting of series of Raman spectra of deoxygenated hemoglobin aqueous solutions was measured by changing excitation wavelengths, revealing the high potential of this laser as a spectroscopic light source.