1,721,064 research outputs found
Raman spectroscopy of femtosecond laser written low propagation loss optical waveguides in Schott N-SF8 glass
No full textWe have performed high repetition rate femtosecond laser bulk modification of TiO2-SiO2 based glass (Schott N-SF8 glass), leading to a decrease in the refractive index near the focal volume. From Raman and X-ray microanalysis we have associated the decrease in the refractive index to a volume expansion due to glass network modifications induced by the laser irradiation. By writing two lines close together we have been able to confine the optical mode and obtain propagation losses of 0.7 dB/cm in the near infrared
Novel chalcogenide optoelectronic and nanophotonic information storage and processing devices
No full textThis project is focused on the application of new electronic and optical materials. In particular it involves examining the use of chalcogenide thin films as phase change and ion conducting glasses for emerging optoelectronic applications. The ability of this group of materials to easily change their state from glass to crystal has meant that they have been widely used in CD's and DVDs. However, their ability to also conduct electrons and ions, promises novel solutions for next generation logic and memory devices which will take us in the short term beyond the limits of the silicon chip and, into the world of neuromorphic cognitive computing (computers that think and adapt). Additionally, this reversible change in the structure of these thin films allows their utilisation in ultra-high speed optical and optoelectronic switches to power the internet and future computers. Three main goals are pursued within this research. First, next generation phase change (PCRAM) and nano-ionic resistive (ReRAM) memory is pursued for faster, non-volatile high density data storage. Secondly, the design of novel processing elements like next generation logic gates enabling neuromorphic cognitive processing and data storage in one structure based on material properties. Finally, the integration of phase change thin films with metamaterial arrays to produce electro-optic and all optical switches for future photonic computers and communication networks
Color tunable perovskite metamaterials
No full textWe show that subwavelength nanostructuring of solution-processed organolead halide perovskite films generates optical resonances whose position can be controlled by design. Perovskite metamaterial create color tuning and strong enhancement of photo- and cathodo-luminescence of the films
Tuneable epsilon near-zero in chalcogenides
No full textThe enormous potential of chalcogenides as compositionally-tuneable alternatives to noble metals for plasmonics and ‘epsilon-near-zero’ (ENZ) photonics can be unlocked using high-throughput materials discovery techniques. Taking advantage of the composition-dependent plasmonic properties of binary and ternary telluride alloys, we show the first amorphous ENZ and plasmonic metasurfaces operating across the UV-VIS spectral range
Data files for A non-volatile chalcogenide switchable hyperbolic metamaterial
No full textThe dataset contains raw and processed data used in the paper “A non-volatile chalcogenide switchable hyperbolic metamaterial” published in Advanced Optical Materials.</span
Reconfigurable hyperbolic metamaterial with negative refraction
No full textRelying on the phase change property of GST chalcogenide glass, we demonstrate a novel reconfigurable hyperbolic metamaterial in which the spectral region of negative refraction can be switched from near infra-red to visible
Chalcogenide metamaterial phase change all-optical switch of nanoscale thickness
No full textNon-volatile, bi-directional, all-optical switching in a phase-change metamaterial delivers high-contrast transmission and reflection modulation at visible and infrared wavelengths in device structures only ~ λ/8 thick
A non-volatile chalcogenide switchable hyperbolic metamaterial
No full textPhase change materials have enabled the realization of dynamic nanophotonic devices with various functionalities. Reconfigurable hyperbolic metamaterials integrated with such elements have been demonstrated in the past but the volatile nature of their optical properties has been a limitation, particularly for applications that require the device to be preserved in a specified state. Here, we report the first proof-of-concept demonstration of a non-volatile, switchable hyperbolic metamaterial based on a chalcogenide glass. By using the Ge2Sb2Te5 (GST) alloy as one of the components of a multilayered nanocomposite structure and exploiting its phase change property, we demonstrate a hyperbolic metamaterial in which the type-I hyperbolic dispersion (ε⊥<0, ε∥>0) and negative refraction can be switched from the near-infrared to the visible region. This opens up new opportunities for reconfigurable device applications, such as imaging, optical data storage and sensing
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