Light- and Neutron-Optical Properties of Holographic Transmission Gratings from Polymer-Ionic Liquid Composites with Submicron Grating Spacing

• Main Authors: Peter Flauger, Mostafa A. Ellabban, Gašper Glavan, Jürgen Klepp, Christian Pruner, Tobias Jenke, Peter Geltenbort, Martin Fally
• Format: Article
• Language: English
• Published: MDPI AG 2019-09-01
• Series: Polymers
• Subjects: polymer composites; ionic liquids; diffraction gratings; neutron optics; thick gratings; holography
• Online Access: https://www.mdpi.com/2073-4360/11/9/1459

We investigate the applicability of polymer-ionic liquid composites as optical elements for light, as well as for slow neutrons. The gratings are recorded using two-beam mixing and are characterized experimentally based on their diffraction properties. We produced a set of samples differing in their thickness, ranging from 10 &#956;m&#8722;100 &#956;m. We demonstrate that it is possible to prepare transmission gratings with a lattice constant of <inline-formula> <math display="inline"> <semantics> <mrow> <mo>&#923;</mo> <mo>=</mo> <mn>480</mn> </mrow> </semantics> </math> </inline-formula> nm, resulting in thick gratings for light, as well as neutrons. The presented samples show low optical losses in the Vis-UV spectrum and exhibit refractive index modulations of about <inline-formula> <math display="inline"> <semantics> <msup> <mn>10</mn> <mrow> <mo>&#8722;</mo> <mn>3</mn> </mrow> </msup> </semantics> </math> </inline-formula> at <inline-formula> <math display="inline"> <semantics> <mrow> <mi>&#955;</mi> <mo>=</mo> <mn>543</mn> </mrow> </semantics> </math> </inline-formula> nm. However, further improvements have to be made to obtain efficient neutron optical components.