Search results for "Generation"

Second Harmonic Generation via Random Quasi-phase Matching in a Periodically Poled Lithium Tantalate Waveguide

2011

We observe second harmonic generation via random quasi phase matching in a 1.5μm periodically poled lithium tantalate. The presence of a slab waveguide allows the comparison between bulk and guided wave configurations.

GENERAZIONE DI SECONDA ARMONICA IN GUIDA D’ONDA IN TANTALATO DI LITIO CONGRUENTE CON POLING PERIODICO E CONVERSIONE DI LUNGHEZZA D’ONDA IN BANDA C + L

2010

Here we show the results obtained by the characterization of a lithium-tantalate based device for second-harmonic-generation and all-optical wavelength conversion. The waveguides have been obtained by proton-exchange in a periodically-poled congruent lithium tantalate substrate.

Sensitivity of SHG-FROG for the characterization of ultrahigh-repetition-rate telecommunication laser sources

2004

International audience; We analyze experimentally the sensitivity of second-harmonic generation frequency-resolved optical gating (SHG-FROG) for the complete intensity and phase characterization of both a sinusoidal beat signal and a train of 1.3 ps pulses at a repetition rate of 160 GHz at 1550 nm. Using a commercially-available optical spectrum analyzer in the SHG-FROG set-up, incident pulses with energies of only 125 and 190 fJ, which correspond to the beat signal and the 1.3 ps pulse train, respectively, have been accurately characterized.

“Seconde generazioni”, identità e partecipazione politica

2020

Il volume si colloca nell’attuale dibattito sociologico sulle “seconde generazioni”. Questo concetto presenta problemi definitori che rievocano questioni più profonde legate alla doppia appartenenza culturale di questi giovani. Il volume si articola in due parti. Nella prima sono approfonditi aspetti teorici ed empirici relativi ai giovani di “seconda generazione” e ai loro percorsi di costruzione identitaria e di partecipazione politica, fortemente segnati dalla mancanza di riconoscimento come cittadini, dalle discriminazioni subite e dai sentimenti di esclusione provati. Nella seconda parte viene effettuata un’analisi quali- quantitativa (con il supporto del software T-Lab) di un corpus e…

The child with overgrowth between clinical variability and genetic heterogeneity

2020

Either in the newborn or in the child overgrowth can be generalized or localized if it is limited to one or more body regions. When overgrowth depends on a metabolic imbalance, or it is constitutional, the excessive growth can be the only clinical sign. In most cases genomic or epigenetic alterations, which affect factors involved in cell proliferation and/or regulation of gene expression (observed also in tumours), are related to overgrowth syndromes, in which excess growth may be associated with dysmorphic features, neuromotor/intellectual disabilities and behavioural disorders. These rare conditions are characterized by clinical and molecular overlap. The paper describes the cases of thr…

Ceļš: Latvijas Universitātes Teoloģijas fakultātes teoloģisks, reliģijpētniecisks un kultūrvēsturisks izdevums, Nr. 67

2017

Inter-generational learning of teachers: what and how do teachers learn from older and younger colleagues?

2018

Abstract: This paper examines how and what teachers learn from their older and younger colleagues. Data were gathered from interviews and written reports from 27 Belgian and Finnish teachers. Thematic qualitative analysis was used. The results revealed differences in what teachers learn from older and younger colleagues. Teachers reported learning innovative teaching methods and ICT skills from younger colleagues, whereas practical information, classroom management skills, self-regulation and community building were learned mainly from older colleagues. Attitudes regarding teaching and different ways of being a teacher were learned from both younger and older colleagues alike. Similarities …

Studio della Nonlinearità Quadratica di Zincoblende per la Generazione di TeraHertz in Guida d'Onda: un Confronto di Cristalli Differenti

2009

DFG TeraHertz generation can approach the quantum efficiency limit with much lower peak powers than bulk experiments. We give details on the model and on the waveguide geometry.

Studio della nonlinearità quadratica di zincoblende per la generazione di TeraHertz in guida d'onda: un confronto di cristalli differenti

2009

DFG TeraHertz generation can approach the quantum efficiency limit with much lower peak powers than bulk experiments. We give details on the model and on the waveguide geometry.

Exploiting the optical quadratic nonlinearity of zinc-blende semiconductors for guided-wave terahertz generation: A material comparison

2010

We present a detailed analysis and comparison of dielectric waveguides made of CdTe, GaP, GaAs and InP for modal phase matched optical difference frequency generation (DFG) in the terahertz domain. From the form of the DFG equations, we derived the definition of a very general figure of merit (FOM). In turn, this FOM enabled us to compare different configurations, by taking into account linear and nonlinear susceptibility dispersion, terahertz absorption, and a rigorous evaluation of the waveguide modes properties. The most efficient waveguides found with this procedure are predicted to approach the quantum efficiency limit with input optical power in the order of kWs.