Abstract

The compensation of high orders of dispersion in sub-20fs chirped-pulse amplification (CPA) laser systems remains a difficult challenge. From the early beginning of sub-ps pulse generation, much effort has been devoted to dispersion management devices and especially to pulse stretchers and pulse compressors which are characterized respectively by large positive and large negative group delay dispersions (GDD). Despite the numerous advantages of the grating pairs introduced in 1968 by E.B Treacy [1], the high level of positive third order dispersion (TOD) prevents these devices from being used in combination with bulk stretchers such as optical fibers [2] or highly dispersive optical glasses. Yet, the use of bulk stretchers would highly simplify the overall design and stability of chirped-pulse amplification (CPA) sources. As soon as 1968, it was shown that TOD could be cancelled or reversed by replacing reflective gratings by transmission gratings engraved on the surface of prisms [3,4]. These first grism compressors were designed far from the Littrow incidence and suffered from low diffraction efficiency. Since then, several other grism designs based on reflective gratings were proposed and demonstrated [5, 6]. By working closer to the Littrow angle, the diffraction efficiency of the gratings could be enhanced to that of conventional grating compressors. However, the thickness of the prisms tends to induce a high level of non linear effects such as self-focusing and self-phase-modulation, which limits the applications of grisms to low energy pulse compression or to down-chirp pulse stretching.

© 2011 Optical Society of America