Thin films of spectral hole burning materials (dyes such as chlorin or phthalocyanines in a matrix) are shown to serve well as highly spectrally selective, linear filters for ultrashort laser pulses. The materials exhibit a large ratio of width of the inhomogeneously broadened absorption band to the width of the zero phonon lines of the photochromic materials and have been used to shape both the phase and amplitude of the output of a Ti:sapphire laser. The preparation of the materials and a variety of their applications are presented.