Variable intracavity spectral windowing in a synchronously pumped femtosecond cw dye laser.

An aperture of variable width has been placed within an intracavity prism sequence in a synchronously pumped femtosecond dye laser. This is shown to permit direct control of the output pulse width in the range approximately 100-500 fsec. Wavelength tunability is achieved by translating the aperture transversely.