High-Damage-Threshold Chirped Mirrors for Next-Generation Ultrafast, High-Power Laser Systems

This study presents the concept of high-damage-threshold chirped mirrors (HDTCMs) for ultrafast high-power laser systems. We describe a novel design method for the fabrication of HDTCMs to simultaneously achieve high reflectivity and high laser-induced damage threshold (LIDT) over a broad bandwidth. In the proposed novel structure, the squared electric field distribution oscillations of the laser pulse stagger each other, leading to a low average squared E-field distribution and effectively enhancing the LIDT. As a proof-of-concept study, an HDTCM is designed based on our simulation. The LIDT of the HDTCM increases by a factor of ~2.3. Moreover, a HDTCM pair is successfully applied in a cross-polarized-wave (XPW) filter, supporting a near Fourier transform limit (FLT) 17.7-fs pulse generation. This concept can be generalized to virtually any optical coating design, thus advancing high damage resistant mirror fabrication to a level well suited to high-power laser applications.