RESUMEN
The referenced article [Opt. Lett.43, 4615 (2018)OPLEDP0146-959210.1364/OL.43.004615] has been retracted by the authors.
RESUMEN
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.e., a difference in RI between two domains) is a critical capability required in photonics for the fabrication of integrated photonics devices, such as, polymer waveguides. In this report, we detail the synthesis of optical polymers tailored to this application, termed Refractive Index Contrast (RIC) polymers, in which the RI of the material can be photopatterned where UV exposure in the presence of a photoacid generator resulted in a permanent increase of RI in the exposed regions thus creating regions of high RIC. This process creates the high RI core of waveguides in a single step and lends itself to rapid fabrication of photonic devices via direct laser writing. Waveguides made from RIC polymers were found to have propagation losses of â¼2 dB/cm at 1550 nm.
RESUMEN
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. Here we report on a new nanocomposite-based system for miniaturized magnetic field sensing. The sensor is based on Dy3+-doped magnetite and cobalt ferrite nanoparticles dispersed in a polymer matrix. Operation is feasible at room temperature and in an unshielded environment. A compact fiber-optic interferometer is used as the detection mechanism with 20 fT/âHz sensitivity. We investigated the magnetic field response of the sensor and demonstrated the measurement of the human heartbeat as a potential application.
RESUMEN
The synthesis of a novel high sulfur content material possessing improved thermomechanical properties is reported via the inverse vulcanization of elemental sulfur (S8) and 1,3,5-triisopropenylbenzene (TIB). A key feature of this system was the ability to afford highly cross-linked, thermosetting materials, where the use of TIB as a comonomer enabled facile control of the network structure and dramatically improved the glass transition temperature (relative to our earlier sulfur copolymers) of poly(sulfur-random-(1,3,5-triisopropenylbenzene)) (poly(S-r-TIB)) materials over a range from T = 68 to 130 °C. This approach allowed for the incorporation of a high content of sulfur-sulfur (S-S) units in the copolymer that enabled thermomechanical scission of these dynamic covalent bonds and thermal reprocessing of the material, which we confirmed via dynamic rheological characterization. Furthermore, the high sulfur content also imparted high refractive index (n > 1.75) and IR transparency to poly(S-r-TIB) copolymers, which offered a route to enhanced optical transmitting materials for IR thermal imaging applications with improved thermomechanical properties.