An effective design method for trapezoidal pulse compression metal multilayer dielectric gratings

Metal multilayer dielectric gratings (MMDGs) for pulse compressors used in high-energy laser systems should enable high efficiency, as well as provide broad bandwidths and high laser-induced damage thresholds. The effects of duty cycle and the ridge slope angle on the MMDG bandwidth is investigated. Keeping all other parameters constant, the bandwidth remains nearly the same with increasing duty cycle and decreasing slope angle. Importantly, the results show a linear relationship between the duty cycle and slope angle of the large bandwidth MMDG. The trapezoidal MMDG designs can be obtained base on the linear relationship and a optimize rectangle grating result. A 200 nm bandwidth (from 700 nm to 900nm) MMDG with efficiency exceeding 90% is obtained using the method. This method can be effectively used in the design of pulse compression grating.