Synthesis of Polycyclic Olefinic Monomers from Norbornadiene for Inverse Vulcanization: Structural and Mechanistic Consequences.

The preparation of high-sulfur content organosulfur polymers has generated considerable interest as an emerging area in polymer science that has been driven by advances in the inverse vulcanization polymerization of elemental sulfur with organic comonomers. While numerous new inverse vulcanized polysulfides have been made over the past decade, insights into the mechanism of inverse vulcanization and structural characterization of the high-sulfur-content copolymers remain limited in scope. Furthermore, the exploration of new molecular architectures for organic comonomer synthesis remains an important frontier to enhance the properties of these new polymeric materials.

Ultralow-quantum-defect single-frequency fiber laser.

A single-frequency distributed-Bragg-reflector fiber laser at 980 nm with a quantum defect of less than 0.6% was developed with a 1.5-cm 12 wt% ytterbium-doped phosphate fiber pumped by a 974.

Injection-locked highly Yb-doped uncoupled-61-core phosphate fiber laser.

Uncoupled multicore fibers are promising platforms for advanced optical communications, optical computing, and novel laser systems. In this paper, an injection-locked highly ytterbium (Yb)-doped uncoupled-61-core phosphate fiber laser at 1030 nm is reported. The 61-core fiber with a core-to-core pitch of 20 μm was fabricated with the stack-and-draw technique.

Sulfenyl Chlorides: An Alternative Monomer Feedstock from Elemental Sulfur for Polymer Synthesis.

A polymerization methodology is reported using sulfur monochloride (SCl) as an alternative feedstock for polymeric materials. SCl is an inexpensive petrochemical derived from elemental sulfur (S) but has numerous advantages as a reactive monomer for polymerization vs S. This new process, termed sulfenyl chloride inverse vulcanization, exploits the high reactivity and miscibility of SCl with a broad range of allylic monomers to prepare soluble, high molar-mass linear polymers, segmented block copolymers, and crosslinked thermosets with greater synthetic precision than achieved using classical inverse vulcanization.

Single-frequency fiber laser at 880 nm.

Single-frequency fiber lasers with extremely low noise and narrow spectral linewidth have found many scientific and practical applications. There is great interest in developing single-frequency fiber lasers at new wavelengths. In this paper, we report a single-frequency Nd-doped phosphate fiber laser operating at 880 nm, which is the shortest demonstrated wavelength for a single-frequency fiber laser thus far, to the best of our knowledge.

Widely wavelength tunable Dy/Er co-doped ZBLAN fiber lasers.

Wavelength tunable dysprosium-erbium (Dy/Er) co-doped ZBLAN (ZrF-BaF-LaF-AlF-NaF) fiber lasers pumped at 980 nm were developed with a bulk grating blazed at 3.1 µm in the Littrow configuration and their performances were investigated. A wavelength tunable range of 674.

Diode-pumped 1.15 W linearly polarized single-frequency Yb-doped phosphate fiber laser.

Compact and robust high-power single-frequency laser oscillators are in great demand for some specific applications where narrow-linewidth lasers with extremely low noise are required. In this paper, we report a single-mode-diode-pumped watt-level single-frequency Yb-doped phosphate fiber laser at 1050 nm based on an all-fiber distributed Bragg reflector cavity. A maximum output power of 1.

Cryogenic C-band wavelength division multiplexing system using an AIM Photonics Foundry process design kit.

Cryogenic environments make superconducting computing possible by reducing thermal noise, electrical resistance and heat dissipation. Heat generated by the electronics and thermal conductivity of electrical transmission lines to the outside world constitute two main sources of thermal load in such systems. As a result, higher data rates require additional transmission lines which come at an increasingly higher cooling power cost.

High sensitivity magnetometer using nanocomposite polymers with large magneto-optic response: retraction.

The referenced article [Opt. Lett.43, 4615 (2018)OPLEDP0146-959210.

Thermal compensation of molded silicone optics.

Optical grade silicone has various properties that make it attractive for solar concentrators, such as excellent transmission across the solar spectrum and flexible moldability for freeform profiles. In this study, a glass-silicone lens structure is proposed to reduce the optothermal effect on the silicone lens. Experimental measurements and simulation modeling results demonstrate that the focal length sensitivity of the glass-silicone lens with respect to temperature can be reduced by a factor of 10 when compared to a silicone lens alone.

Magneto-optical properties of highly Dy doped multicomponent glasses.

Due to their large effective magnetic moment, Dy-doped materials have attracted much interest for magneto-optical applications. In this paper, we report highly Dy doped multicomponent glasses with concentrations from 40 wt.% to 75 wt.

"An Important Part of Who I am": The Predictors of Dietary Adherence among Weight-Loss, Vegetarian, Vegan, Paleo, and Gluten-Free Dietary Groups.

Weight-loss diets are notorious for their low adherence, which is a barrier to efforts to reduce population rates of overweight and obesity. However, there is some evidence that adherence is better among people on other kinds of diets, such as vegan and gluten free. This study aimed to explore the predictors of dietary adherence across five restrictive dietary patterns (vegan, vegetarian, paleo, gluten free, and weight loss).

Refractive Index Contrast Polymers: Photoresponsive Systems with Spatial Modulation of Refractive Index for Photonics.

The development of an intriguing concept using optical polymers for photonics is reported to enable modulation of refractive index (RI) in solution cast thin films with precise spatial control. While extensive efforts in polymer science have focused on methods to prepare optically transparent polymers with high RI, the creation of photoresponsive polymer systems to spatially adjust the refractive index upon irradiation is a distinct technical challenge requiring development of materials amenable to this process. The ability to create refractive index contrast (i.

100th Anniversary of Macromolecular Science Viewpoint: High Refractive Index Polymers from Elemental Sulfur for Infrared Thermal Imaging and Optics.

Optical technologies in the midwave and long wave infrared spectrum (MWIR, LWIR) are important systems for high resolution thermal imaging in near, or complete darkness. While IR thermal imaging has been extensively utilized in the defense sector, application of this technology is being driven toward emerging consumer markets and transportation. In this viewpoint, we review the field of IR thermal imaging and discuss the emerging use of synthetic organic and hybrid polymers as novel IR transmissive materials for this application.

Investigation of ion-ion interaction effects on Yb-doped fiber amplifiers.

Ytterbium (Yb)-doped materials have been widely used for high efficiency high energy laser sources at the 1 µm wavelength region because of their very low quantum defect and the unique simple energy level structure of Yb, resulting in no excited-state absorption and low occurrence probability of deleterious ion-ion interaction processes. It has been generally recognized that these ion-ion interaction processes have very little influence on the operation of Yb-doped fiber lasers at low and moderate power levels. However, our recent study shows that the performance of Yb-doped fiber amplifiers operating at low power levels is still influenced by the ion-ion interaction processes due to the large amount of population at the upper laser level F.

Infrared Fingerprint Engineering: A Molecular-Design Approach to Long-Wave Infrared Transparency with Polymeric Materials.

Optical technologies in the long-wave infrared (LWIR) spectrum (7-14 μm) offer important advantages for high-resolution thermal imaging in near or complete darkness. The use of polymeric transmissive materials for IR imaging offers numerous cost and processing advantages but suffers from inferior optical properties in the LWIR spectrum. A major challenge in the design of LWIR-transparent organic materials is that nearly all organic molecules absorb in this spectral window which lies within the so-called IR-fingerprint region.

Numerical investigation of GHz repetition rate fundamentally mode-locked all-fiber lasers.

GHz repetition rate fundamentally mode-locked lasers have attracted great interest for a variety of scientific and practical applications. A passively mode-locked laser in all-fiber format has the advantages of high stability, maintenance-free operation, super compactness, and reliability. In this paper, we present numerical investigation on passive mode-locking of all-fiber lasers operating at repetition rates of 1-20 GHz.

Silicone optical elements for cost-effective freeform solar concentration.

The use of silicone optical elements is demonstrated for a concentrated photovoltaic system. These components show over 96% transmission through most of the solar spectrum and excellent temperature stability. Unique moldability enables the use of complex freeform designs.

The psychological characteristics of people consuming vegetarian, vegan, paleo, gluten free and weight loss dietary patterns.

Objective: Previous research has identified several psychological factors associated with dietary restriction but has focused almost exclusively on the subcategory of people following a weight loss diet. Little is known about the psychological factors associated with other kinds of restrictive dietary patterns. Furthermore, it remains unclear whether the identified psychological characteristics of dieters (e.

High sensitivity magnetometer using nanocomposite polymers with large magneto-optic response.

Miniaturized magnetic field sensors are increasingly used in various applications, such as geophysical exploration for minerals and oil, volcanology, earthquake studies, and biomedical imaging. Existing magnetometers lack either the spatial or the temporal resolution or are restricted to costly shielded labs and cannot operate in an unshielded environment. Increasing spatio-temporal resolution would allow for real-time measurements of magnetic fluctuations with high resolution.

One Dimensional Photonic Crystals Using Ultrahigh Refractive Index Chalcogenide Hybrid Inorganic/Organic Polymers.

We report on the fabrication of wholly polymeric one-dimensional (1-D) photonic crystals (i.e., Bragg reflectors, Bragg mirrors) via solution processing for use in the near (NIR) and the short wave (SWIR) infrared spectrum (1-2 μm) with very high reflectance ( ∼ 90-97%).

Nonlinear optical components for all-optical probabilistic graphical model.

The probabilistic graphical models (PGMs) are tools that are used to compute probability distributions over large and complex interacting variables. They have applications in social networks, speech recognition, artificial intelligence, machine learning, and many more areas. Here, we present an all-optical implementation of a PGM through the sum-product message passing algorithm (SPMPA) governed by a wavelength multiplexing architecture.

Optical and mechanical tolerances in hybrid concentrated thermal-PV solar trough.

Hybrid thermal-PV solar trough collectors combine concentrated photovoltaics and concentrated solar power technology to harvest and store solar energy. In this work, the optical and mechanical requirements for optimal efficiency are analyzed using non-sequential ray tracing techniques. The results are used to generate opto-mechanical tolerances that can be compared to those of traditional solar collectors.

Power scalable 10 W 976 nm single-frequency linearly polarized laser source.

A 10 W level 976 nm single-frequency linearly polarized laser source was demonstrated with a two-stage all-fiber amplifier configuration. The continuous-wave output power of 10.1 W was obtained from the second stage amplifier by using a 20/130 μm single-mode, polarization maintaining, 1.