Efficient instantaneous optical switching and frequency conversion on a femtosecond time scale

In this paper, new results about a transient femtosecond index grating in barium fluoride has been presented. There is a strong indication that the lifetime of the grating is only limited by the pulse width of the laser. Additionally, it is shown how the transient grating promotes highly efficient third-harmonic generation and diffraction due to a self phase matching mechanism. The immediate build-up and decay opens the way to an application as a femtosecond switching device.