Highly Sensitive and Cost‐Effective Polymeric‐Sulfur‐Based Mid‐Wavelength Infrared Linear Polarizers with Tailored Fabry–Pérot Resonance

Abstract

Inverse‐vulcanized polymeric sulfur has received considerable attention for application in waste‐based infrared (IR) polarizers with high polarization sensitivities, owing to its high transmittance in the IR region and thermal processability. However, there have been few reports on highly sensitive polymeric sulfur‐based polarizers by replication of pre‐simulated dimensions to achieve a high transmission of the transverse magnetic field (TTM) and extinction ratio (ER). Herein, a 400‐nanometer‐pitch mid‐wavelength infrared bilayer linear polarizer with self‐aligned metal gratings is introduced on polymeric sulfur gratings integrated with a spacer layer (SM‐polarizer). The dimensions of the SM‐polarizer can be closely replicated using pre‐simulated dimensions via a systematic investigation of thermal nanoimprinting conditions. Spacer thickness is tailored from 40 to 5100 nm by adjusting the concentration of polymeric sulfur solution during spin‐coating. A tailored spacer thickness can maximize TTM in the broadband MWIR region by satisfying Fabry–Pérot resonance. The SM‐polarizer yields TTM of 0.65, 0.59, and 0.43 and ER of 3.12 × 103, 5.19 × 103, and 5.81 × 103 at 4 µm for spacer thicknesses of 90, 338, and 572 nm, respectively. This demonstration of a highly sensitive and cost‐effective SM‐polarizer opens up exciting avenues for infrared polarimetric imaging and for applications in polarization manipulation.

Synthesis of Deuterated and Sulfurated Polymers by Inverse Vulcanization: Engineering Infrared Transparency via Deuteration

“…Furthermore, for the deutero poly­(S- r -DIB) optical grating at 3.39 μm, the experimentally measured diffraction angle (θ exp = 33.7°) was found to be in good agreement with the theoretical value (θ theoretical = 34.5°) at 3.39 μm for the deutero poly­(S- r -DIB) optical grating. Related work on the fabrication of MWIR polarizers from poly­(S- r -DIB) has been reported, , with notable optical performance improvements by Cho et al, achieved through superior nanoimprint methods for MWIR polarizer fabrication.…”

“…Furthermore, spectral MWIR windows from ∼4.2 to 5.0 μm are rendered unusable for numerous MWIR optics and photonic applications (e.g., defense) because of carbon dioxide atmospheric absorption, further valorizing the MWIR window from 3.3 to 4.2 μm for application development. A breakthrough in polymer chemistry and optical sciences reported a decade ago was the inverse vulcanization polymerization of elemental sulfur (S 8 ) with proteo -1,3-diisopropenylbenzene (DIB), where the reduction of MWIR absorbing organic C–H bonds dramatically enhanced the IR transparency. − These hybrid polymers are analogous to inorganic chalcogenide glasses and hence have been referred to as chalcogenide hybrid inorganic/organic polymers (CHIPs) when used for optical applications. ,− …”

Recent Progress in Sulfur-Containing High Refractive Index Polymers for Optical Applications

“…Sulfur-containing polymers have found uses in a wide range of applications, e.g., as cathode materials in lithium-ion batteries, − memory devices, , conducting polymers, − and optical materials. − Furthermore, sulfur-containing polymers with high industrial importance are polysulfones and polysulfides. − Sulfur-containing polythiophene films were recently demonstrated with electrochromism, chemochromism, or sensory characteristics. − The combination of conjugation and high molar refraction of sulfur gives polythiophenes superiority in terms of RI. Poly­(3-alkythiophenes) (P3AT) provide immense scope in organic field effect transistors (OFETs) and photovoltaic devices by virtue of high field effect mobilities.…”

Enhancement of thermomechanical properties of sulfur-rich polymers by post-thermal treatment

“…More than 70 million tons of elemental sulfur are produced annually 2,3 and due to its limited demand, there are 7 million tons surplus of elemental sulfur every year. 4 Recently, sulfur-rich polymers have been introduced owing to their high utility and multifunctionality in various fields, including batteries, 5 infrared (IR) optics, 6,7 mercury adsorption, 8 and triboelectric energy harvesting. 9,10 Inverse vulcanization is one of bulk polymerization between chalcogens (i.e.…”