A
prism compressor is an
optical device used to shorten the duration of a positively chirped
ultrashort laser pulse by giving different
wavelength components a different time delay. It typically consists of two
prisms and a mirror. Figure 1 shows the construction of such a compressor. Although the
dispersion of the prism material causes different wavelength components to travel along different paths, the compressor is built such that all wavelength components leave the compressor at different times, but in the same direction. If the different wavelength components of a
laser pulse were already separated in time, the prism compressor can make them overlap with each other, thus causing a shorter pulse.