Results 81 to 90 of about 821 (229)

Mode Optimization and Polarization Control in VCSELs with Sub-Wavelength Gratings

IEEE Photonics Journal
We have demonstrated the integration of sub-wavelength gratings (SWG) into a 795 nm vertical cavity surface emitting laser (VCSEL) with inverse surface relief to achieve coordinated control of the mode and polarization. At a grating period of around 0.5 &
Yongli Wang, Chuanchuan Li, Yang Zhang, Jian Li, Xin Wei   +4 more
doaj   +1 more source

Ultra‐Fast and Energy‐Efficient PZT Optical Tunable Delay Lines for Programmable Photonic Systems

Laser &Photonics Reviews, EarlyView.
Thin‐film PZT enables optical tunable delay lines that simultaneously offer sub‐nanosecond switching, low propagation loss, and zero‐static‐power programmability. A five‐bit on‐chip delay line provides a maximum delay of 387.5 ps with a resolution of 12.5 ps, while reconfigurable MZI splitting ratios further enable non‐volatile optical arbitrary ...
Cunyu Shi, Chenlei Li, Wei Chen, Shengjie Tang, Tao Shu, Haojie Zhu, Haorui Liu, Yueyang Zhang, Long Zhang, William Shieh, Feng Qiu, Daoxin Dai   +11 more
wiley   +1 more source

Visible Octave Frequency Combs in Silicon Nitride Nanophotonic Waveguides Driven by Ti:Sapphire Lasers

Laser &Photonics Reviews, EarlyView.
Chip‐based frequency combs are usually pumped from telecom wavelengths, far from the visible. This work instead pumps close to the visible with a Ti:sapphire laser ‐ the source behind the original optical frequency combs and now becoming chip‐integrable‐ and lets silicon‐nitride waveguides convert it into efficient, octave‐spanning visible‐to‐infrared ...
Abdullah Alabbadi, Ewan Allan, Hanna Ostapenko, Pablo Castro‐Marín, Derryck T. Reid, Pascal Del'Haye   +5 more
wiley   +1 more source

Disposition Model for Permafrost Degradation in Mountainous Regions

Permafrost and Periglacial Processes, EarlyView.
ABSTRACT Permafrost is a widespread thermal phenomenon in Arctic and high mountain regions that, in combination with steep terrain, exerts a key control on slope stability. Its degradation in response to climatic warming can modify the likelihood and timing of rockfall, debris flow and related mass movements. Robust information on the current state and
Peter Mani, Simon Allen, Mathias Bavay, Nils Hählen, Markus Stoffel   +4 more
wiley   +1 more source

Repeated Pleistocene Permafrost Episodes in the Western Pannonian Basin

Permafrost and Periglacial Processes, EarlyView.
ABSTRACT Concerning the study of past periglacial processes, the Pannonian Basin is a key area as it contains the southernmost frost polygons found in Central Europe. The presence or absence of permafrost is still, however, a matter of debate, and data on the timing of frost action are also scarce.
Krisztina Sebe, Ágnes Novothny, Gergely Surányi, Barbara Varga, László Fodor, Gábor Csillag   +5 more
wiley   +1 more source

Internal Structure, Kinematics, and Prehistory of Frozen Debris Lobe‐A (FDL‐A), Brooks Range, Alaska

Permafrost and Periglacial Processes, EarlyView.
ABSTRACT Frozen Debris Lobe‐A (FDL‐A)—one of hundreds of FDLs in the Brooks Range of northern Alaska—is a slow‐moving landslide in permafrost that has been the subject of research since 2008 due to its close proximity to the Dalton Highway. Here, we synthesize more than a decade's worth of climate and surface measurements of monitored FDLs, and the ...
Margaret M. Darrow, Esther L. Babcock, Ben A. Leshchinsky   +2 more
wiley   +1 more source

Restoring Lateral Connectivity to Anthropogenic Riverscapes: Six Lessons From Stage Zero

River Research and Applications, EarlyView.
ABSTRACT Centuries of river modification, particularly straightening and incision, have severely reduced lateral connectivity between rivers and their floodplains. As a result, Stage 0 riverscapes, characterised by high lateral connectivity (e.g., anastomosing or wetland riverscapes), are now rare in anthropogenic landscapes.
Richard J. Mason, Matthew F. Johnson, Ben Eardley, Matthew J. Hemsworth, Arnaud Foret, Luca Mao, Matt Parr, Alan Puttock, Richard E. Brazier   +8 more
wiley   +1 more source

The Hidden Harvest: Harnessing Colorado's Geodiversity and Environmental Heterogeneity for Sustainable Agritourism

Sustainable Development, EarlyView.
ABSTRACT Colorado's geologic, pedologic, topographic, hydrological, and climatic contrasts create strong but under‐synthesized opportunities for sustainable agritourism. This review investigates how geodiversity, and the broader environmental heterogeneity within which it operates, can be used to diversify farm income, strengthen place‐based visitor ...
Bonface O. Manono
wiley   +1 more source

Rigid and flexible azopolymers modified with donor/acceptor groups. Synthesis and photochromic behavior

eXPRESS Polymer Letters, 2011
The aim of this work is to investigate the photochromic behavior and nano-structuration capacity of azo-polymers with different architectures and main chain flexibilities, modified with donor/acceptor groups.
doaj   +1 more source

Evaluation of prestress losses in concrete beams using destructive and non‐destructive methods

Structural Concrete, EarlyView.
Abstract Over the past few decades, prestressing techniques have become essential in the construction of key structures, infrastructure, and bridges. The serviceability and safety of prestressed concrete (PC) elements are closely tied to the effectiveness of the prestressing process.
A. N. Consiglio, G. Muciaccia, G. Rosati
wiley   +1 more source