Wavelength-tunable narrow-linewidth gaseous Raman laser.

Gaseous Raman lasers cover a range of wavelengths but lack wavelength tunability. Here, a 1cm-1 linewidth 532 nm laser was used as a pump laser, and with a narrow-linewidth seed laser injection, a narrow-linewidth first Stokes (S1) Raman laser was achieved. By tuning the wavelength of the seed laser, a tuning range of S1 up to 1cm-1 was obtained. The wavelengths of the first anti-Stokes and second Stokes lasers could also be tuned. A theoretical model was developed, and spectral profiles of Raman lasers from experiments and simulations agreed well; further simulation predicted that the linewidth of S1 could be compressed to as narrow as 0.01cm-1 under optimal conditions. A universal method of fine-tunable Raman lasers is presented that can be utilized in several important applications.