Department of Electrical Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
Missiles and Fire Control, Lockheed Martin Corporation, Orlando, FL, 32819, USA.
Adv Mater. 2018 Sep;30(39):e1803628. doi: 10.1002/adma.201803628. Epub 2018 Aug 13.
A novel photothermal process to spatially modulate the concentration of sub-wavelength, high-index nanocrystals in a multicomponent Ge-As-Pb-Se chalcogenide glass thin film resulting in an optically functional infrared grating is demonstrated. The process results in the formation of an optical nanocomposite possessing ultralow dispersion over unprecedented bandwidth. The spatially tailored index and dispersion modification enables creation of arbitrary refractive index gradients. Sub-bandgap laser exposure generates a Pb-rich amorphous phase transforming on heat treatment to high-index crystal phases. Spatially varying nanocrystal density is controlled by laser dose and is correlated to index change, yielding local index modification to ≈+0.1 in the mid-infrared.
一种新的光热工艺，可在多组分 Ge-As-Pb-Se 硫属玻璃薄膜中空间调制亚波长、高折射率纳米晶体的浓度，从而形成具有光学功能的红外光栅。该工艺导致形成具有前所未有的超宽带宽的超低分散的光学纳米复合材料。空间定制的折射率和色散修饰可实现任意折射率梯度的创建。亚带隙激光曝光会生成富含 Pb 的非晶相，经热处理后转变为高折射率晶体相。纳米晶体密度的空间变化由激光剂量控制，并与折射率变化相关，在中红外区产生约+0.1 的局部折射率修饰。
