Park Rowoon, Park Sang-Hyuk, Kim Minwoo, Kim Minju, Park Seungho, Kwon Young Woo, Lee Songyi, Kyhm Kwangseuk, Hong Suck Won, Taylor Robert A
Department of Optics and Mechatronics Engineering, Department of Cogno-Mechatronics Engineering, and College of Nanoscience and Nanotechnology, Pusan National University, Busan 46241, Republic of Korea.
Engineering Research Center for Color-Modulated Extra-Sensory Perception Technology, Pusan National University, Busan 46241, Republic of Korea.
ACS Appl Mater Interfaces. 2025 Jul 30;17(30):43476-43487. doi: 10.1021/acsami.5c10300. Epub 2025 Jul 18.
We have successfully produced an ultrathin freely suspended GO film, which is a biomimetic structure inspired by the transparent dragonfly wing structure. Based on a colloidal self-assembly process over a large area, solvent evaporation was applied within a limited opening geometry. The free-standing GO film shows a significant enhancement of the nonlinear optical absorption, where saturable absorption and photoinduced absorption were observed at dramatically decreased excitation fluence compared with other work on GO films dispersed on substrates. Surprisingly, we also found that free-standing GO films are beneficial for compressing femtosecond pulses around 800 nm. Using a frequency-resolved optical gating as well as an open aperture Z-scan method, the origin was found to be associated with two effects. While the pulse shortening results from saturable absorption, the chirp effect is also suppressed due to the presence of an inflection point around 800 nm in the refractive index spectrum of free-standing GO film.
我们成功制备了一种超薄自由悬浮的氧化石墨烯（GO）薄膜，它是受透明蜻蜓翅膀结构启发的仿生结构。基于大面积的胶体自组装过程，在有限的开口几何结构内进行溶剂蒸发。这种独立的GO薄膜显示出非线性光学吸收的显著增强，与其他关于分散在基底上的GO薄膜的工作相比，在显著降低的激发通量下观察到了饱和吸收和光致吸收。令人惊讶的是，我们还发现独立的GO薄膜有利于压缩800nm左右的飞秒脉冲。通过频率分辨光学门控以及开孔Z扫描方法，发现其起源与两种效应有关。虽然脉冲缩短是由饱和吸收导致的，但由于独立GO薄膜折射率谱在800nm左右存在一个拐点，啁啾效应也得到了抑制。
