Institute of Laser Engineering, Osaka University, 2-6, Yamada-oka, Suita, Osaka 565-0871, Japan.
Opt Lett. 2010 Jun 1;35(11):1783-5. doi: 10.1364/OL.35.001783.
Segmented (tiled) grating arrays are being intensively investigated for petawatt-scale pulse compression due to the expense and technical challenges of fabricating monolithic diffraction gratings with apertures of over 1m. However, the considerable freedom of motion among grating segments complicates compression and laser focusing. We constructed a real compressor system using a segmented grating for an 18cm aperture laser beam of the Gekko MII 100TW laser system at Osaka University. To produce clean pulse shapes and single focal spots tolerant of misalignment and groove density difference of grating tiles, we applied a new compressor scheme with image rotation in which each beam segment samples each grating segment but from opposite sides. In high-energy shots of up to 50J, we demonstrated nearly Fourier-transform-limited pulse compression (0.5ps) with an almost diffraction-limited spot size (20microm).
分段（平铺）光栅阵列由于制造孔径超过 1m 的整体衍射光栅的费用和技术挑战，正在被深入研究用于皮秒级脉冲压缩。然而，光栅段之间相当大的自由度使得压缩和激光聚焦变得复杂。我们使用分段光栅为大阪大学的 Gekko MII 100TW 激光系统的 18cm 孔径激光束构建了一个真正的压缩器系统。为了产生干净的脉冲形状和单个焦点光斑，即使光栅瓦片的对准和槽密度存在差异也能容忍，我们应用了一种新的带有图像旋转的压缩器方案，其中每个光束段从相反的两侧对每个光栅段进行采样。在高达 50J 的高能射击中，我们演示了几乎傅里叶变换极限的脉冲压缩（0.5ps），并且光斑尺寸几乎达到衍射极限（20 微米）。
