Direct Assessment Of The Phase Matching Properties Of New Nonlinear Materials

1987 ◽  
Author(s):  
Stephan P. Velsko
Keyword(s):  
Phase Matching ◽  
Nonlinear Materials ◽  
Direct Assessment

Random quasi-phase-matching in bulk polycrystalline isotropic nonlinear materials

Nature ◽  
2004 ◽  
Vol 432 (7015) ◽  
pp. 374-376 ◽  
Author(s):  
M. Baudrier-Raybaut ◽  
R. Haïdar ◽  
Ph. Kupecek ◽  
Ph. Lemasson ◽  
E. Rosencher
Keyword(s):  
Phase Matching ◽  
Nonlinear Materials ◽  
Quasi Phase Matching

Assessment of Cognitive Load in Multimedia Learning Using Dual-Task Methodology

2002 ◽  
Vol 49 (2) ◽  
pp. 109-119 ◽  
Author(s):  
Roland Brünken ◽  
Susan Steinbacher ◽  
Jan L. Plass ◽  
Detlev Leutner
Keyword(s):  
Cognitive Load ◽  
Dual Task ◽  
Cognitive Load Theory ◽  
Multimedia Learning ◽  
Learning Systems ◽  
Learning Materials ◽  
New Approach ◽  
Direct Assessment ◽  
Load Theory ◽  
Audiovisual Presentation

Abstract. In two pilot experiments, a new approach for the direct assessment of cognitive load during multimedia learning was tested that uses dual-task methodology. Using this approach, we obtained the same pattern of cognitive load as predicted by cognitive load theory when applied to multimedia learning: The audiovisual presentation of text-based and picture-based learning materials induced less cognitive load than the visual-only presentation of the same material. The findings confirm the utility of dual-task methodology as a promising approach for the assessment of cognitive load induced by complex multimedia learning systems.

Development of an IRT-based Direct Assessment of Preschool Science

2008 ◽  
Author(s):  
Daryl B. Greenfield ◽  
Ximena Dominguez ◽  
Janna Marie Fuccillo ◽  
Michelle Filomena Maier ◽  
Ariela Caren Greenberg
Keyword(s):  
Direct Assessment ◽  
Preschool Science

Direct Assessment of Functional Status Scale

1989 ◽  
Author(s):  
David A. Loewenstein ◽  
Ellen Amigo ◽  
Ranjan Duara ◽  
Andrew Guterman ◽  
Deborah Hurwitz ◽  
...  
Keyword(s):  
Functional Status ◽  
Direct Assessment

scholarly journals High Field Single- to Few-Cycle THz Generation with Lithium Niobate

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 183
Author(s):  
Xing Zhu ◽  
David R. Bacon ◽  
Julien Madéo ◽  
Keshav M. Dani
Keyword(s):  
Lithium Niobate ◽  
Condensed Matter ◽  
High Harmonic ◽  
Nonlinear Spectroscopy ◽  
Optical Rectification ◽  
Phase Matching ◽  
Nonlinear Phenomena ◽  
Generation Efficiency ◽  
Basic Principles ◽  
Thz Generation

The transient terahertz (THz) pulse with high peak field has become an important tool for matter manipulation, enabling many applications such as nonlinear spectroscopy, particle acceleration, and high harmonic generation. Among the widely used THz generation techniques, optical rectification in lithium niobate (LN) has emerged as a powerful method to achieve high fields at low THz frequencies, suitable to exploring novel nonlinear phenomena in condensed matter systems. In this review, we focus on introducing single- to few-cycle THz generation in LN, including the basic principles, techniques, latest developments, and current limitations. We will first discuss the phase matching requirements of LN, which leads to Cherenkov-like radiation, and the tilted pulse front (TPF) technique. Emphasis will be put on the TPF technique, which has been shown to improve THz generation efficiency, but still has many limitations. Different geometries used to produce continuous and discrete TPF will be systematically discussed. We summarize the advantages and limitations of current techniques and future trends.

scholarly journals Laser Pulse Shortening via Zero-Dispersion Phase Matching of Parametric Raman Interactions in Crystals

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 19
Author(s):  
Sergei N. Smetanin ◽  
Michal Jelínek ◽  
Dmitry P. Tereshchenko ◽  
Mikhail N. Ershkov ◽  
Václav Kubeček
Keyword(s):  
Laser Pulse ◽  
Short Pulse ◽  
Matching Condition ◽  
Phase Matching ◽  
Dispersion Phase ◽  
Birefringent Crystal ◽  
Raman Lasers ◽  
Birefringent Crystals ◽  
Phase Matching Condition ◽  
Ultra Short Pulse

We propose and study the conditions of zero-dispersion phase matching for parametric Raman interactions in birefringent crystals differing by anisotropy of zero-dispersion wavelength and allowing for the spectral tuning of the zero-dispersion phase-matching condition. We choose a highly birefringent crystal of calcite having a wide zero-dispersion anisotropy range for the demonstration of new effects of laser pulse shortening in parametric Raman lasers with spectrally tunable zero-dispersion phase matching. We demonstrate the anti-Stokes (1168 nm) and multi-Stokes (1629 nm) picosecond pulse shortening and self-separation of single 80-ps ultra-short pulse from the zero-dispersion phase-matched parametric Raman lasers that are based on the calcite crystal without using any electro-optical device.

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