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Creators/Authors contains: "Kim, Kyung‐Jo"

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  1. Abstract In this study, the first fabrication of phase‐shifted Bragg gratings utilizing chalcogenide hybrid inorganic/organic polymers (CHIPs) is presented based on poly(sulfur‐random‐(1,3‐isopropenylbenzene) to measure the thermo‐optic coefficient (TOC) of this new class of optical polymers. The unique properties ofCHIPs, such as high index contrast and low optical losses, are leveraged to fabricate Bragg gratings that enable precise determination of the TOC and glass transition temperature (Tg) of these polymers. The optical measurement introduces a novel technique to measure the TOC and Tgof optical polymers which can be difficult to determine using traditional methods such as differential scanning calorimetry (DSC) after fabrication into photonic device constructs. The findings demonstrate thatCHIPs exhibit low thermo‐optic (TO) effects, making them exceptionally well‐suited for the development of thermally stable photonic integrated circuits. 
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  2. Abstract The development of an organic optical glass, termed, disulfide glass (DSG), is reported as a new polymer for commodity plastic optics and thin film photonic applications. This low‐cost thermoset polymer possesses excellent transparency across the visible and infrared spectrum comparable to the best optical plastic to date, poly(methyl methacrylate), while having superior refractive index (n≈ 1.6). DSG can be fabricated into defect‐free, thick optical glass by bulk addition polymerization of two commodity monomers (sulfur monochloride, 1,3,5‐triallyl isocyanurate) via a new polymerization, sulfenyl chloride inverse vulcanization. The robust mechanical properties and optical clarity of DSG enable fabrication of precision optics (lenses, prisms) via diamond turn machining to demonstrate the manufacturability of DSG for commodity plastic optics. Finally, the synthetic modularity of DSG is demonstrated to form solution processable forms for the fabrication of thin film polymer photonic devices, negative tone polymer photoresists, and micropatterned arrays. 
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  3. Abstract The development of a low‐cost photopolymer resin to fabricate optical glass of high refractive index for plastic optics is reported. This new free radically polymerizable photopolymer resin, termed, disulfide methacrylate resin (DSMR) is synthesized by the direct addition of allyl methacrylate to a commodity sulfur petrochemical, sulfur monochloride (S2Cl2). The rapid rates of free radical photopolymerization confer significant advantages in preparing high‐quality, bulk optical glass. The low‐cost, optical glass produced from this photopolymer possesses a desirable combination of high refractive index (n ≈ 1.57–1.59), low birefringence (Δn < 10−4), high glass transition values (Tg ≈ 100 °C), along with optical transparency rivaling, or exceeding that of poly(methyl methacrylate) (PMMA) as indicated by very low optical absorption coefficients (α < 0.05 cm−1at 1310 nm) measured for thick glass DSMR photopolymer samples (diameter (D) = 25 mm; thickness = 1–30 mm). The versatile manufacturability of DSMR photopolymers for both molding and diamond turn machining methods is demonstrated to prepare precision optics and nano‐micropatterned arrays. Finally, large‐scale 3D printing vat photopolymerization of DSMR using high‐area rapid printing digital light processing additive manufacturing is demonstrated. 
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  4. Abstract Optical polymer‐based integrated photonic devices are gaining interest for applications in optical packaging, biosensing, and augmented/virtual reality (AR/VR). The low refractive index of conventional organic polymers has been a barrier to realizing dense, low footprint photonic devices. The fabrication and characterization of integrated photonic devices using a new class of high refractive index polymers, chalcogenide hybrid inorganic/organic polymers (CHIPs), which possess high refractive indices and lower optical losses compared to traditional hydrocarbon‐based polymers, are reported. These optical polymers are derived from elemental sulfur via the inverse vulcanization process, which allows for inexpensive monomers to be used for these materials. A facile fabrication strategy using CHIPs via lithography is described for single‐mode optical waveguides, Y junction splitters, multimode interferometers (MMIs), and high Q factor ring resonators, along with device characterization. Furthermore, propagation losses of 0.4 dB cm−1near 1550 nm wavelength, which is the lowest measured loss in non‐fluorinated optical polymer waveguides, coupled with the benefits of low cost materials and manufacturing are reported. Ring resonators with Q factor on the order of 6 × 104and cavity finesse of 45, which are some of the highest values reported for optical polymer‐based ring resonators, are also reported. 
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