Applications of High Resolution Coherent Raman Spectroscopy

In recent years, the development of improved laser sources of high power and narrow linewidth has led to significant advances in high resolution Coherent Raman spectroscopies such as CARS (Coherent Anti-Stokes Raman Spectroscopy) and SRS (Stimulated Raman Gain/Loss Spectroscopy). The apparatus at Oregon State University is representative of current capabilities and consists of a cw ring dye laser whose output is increased in a three-stage dye amplifier pumped by the 532 nm output of a seeded, single frequency Nd:YAG pulsed laser. The resolution is thus limited by the Fourier transform of the amplifying pulse which is 5-10 ns for most commercial Nd:YAG lasers. Very recently, we have extended this using a custom long-pulse Nd:YAG laser of 30-50 ns 532 nm pulse duration.1