Jeon Taeyoon, Myung Jieun, Choi Changsoon, Shayegan Komron, Lewis Scott M, Scherer Axel
Applied Physics and Materials Science, California Institute of Technology, 1200 East California Boulevard, MC 200-79, Pasadena, CA 91125, USA.
Sensors (Basel). 2023 Dec 14;23(24):9810. doi: 10.3390/s23249810.
Mid-infrared optics require optical coatings composed of high- and low-refractive-index dielectric layers for the design of optical mirrors, filters, and anti-reflection coatings. However, there are not many technologies for depositing a material with a refractive index of less than 2 and a low loss in the mid-infrared region. Here, we present a unique deposition method of crosslinked polyethylene thin film for mid-IR optical filter design. Polyethylene has a refractive index of 1.52 in the mid-infrared region and a small number of absorption peaks, so it is useful for making optical filters in the mid-infrared region. Only 1 keV of energy is required to crosslink the entire film by irradiating an electron beam while depositing polyethylene. In addition, crosslinked polyethylene thin film has high mechanical strength, so there is no cracking or peeling when used with germanium. This allows for the use of crosslinked polyethylene as a low refractive index for mid-infrared optical coating.
中红外光学器件需要由高折射率和低折射率介电层组成的光学涂层来设计光学镜、滤光片和抗反射涂层。然而，在中红外区域沉积折射率小于2且损耗低的材料的技术并不多。在此，我们提出一种用于中红外滤光片设计的交联聚乙烯薄膜的独特沉积方法。聚乙烯在中红外区域的折射率为1.52，且吸收峰较少，因此对于制造中红外区域的光学滤光片很有用。在沉积聚乙烯时通过照射电子束交联整个薄膜仅需1 keV的能量。此外，交联聚乙烯薄膜具有较高的机械强度，因此与锗一起使用时不会出现开裂或剥落现象。这使得交联聚乙烯可作为中红外光学涂层的低折射率材料使用。
