1,721,008 research outputs found
Polaritonics: From microcavities to sub-wavelength confinement
No full textFollowing the initial success of cavity quantum electrodynamics in atomic systems, strong coupling between light and matter excitations is now achieved in several solid-state set-ups. In those systems, the possibility to engineer quantum emitters and resonators with very different characteristics has allowed access to novel nonlinear and non-perturbative phenomena of both fundamental and applied interest. In this article, we will review some advances in the field of solid-state cavity quantum electrodynamics, focussing on the scaling of the relevant figures of merit in the transition from microcavities to sub-wavelength confinement.</p
Microstructural modification of LiNbO3 crystals induced by femtosecond laser irradiation
No full textIn this work we report on the study of microstructural modifications induced by femtosecond laser irradiation on Lithium Niobate crystals by means of optical microscopy and micro-Raman spectroscopy
Microstructural modification of LiNbO3 crystals induced by femtosecond laser irradiation
No full textMicrostructural modifications were induced by femtosecond laser irradiation on lithium mobate (LN) crystals and investigated by means of optical microscopy and micro-Raman spectroscopy. Commercial z-cut congruent LN substrates were irradiated with focused ultra-short laser pulses at 810 nm, generated by a Ti:Sapphire oscillator or an amplified Ti:Sapphire laser system.
At the focus region, either refractive index changes or material removal were observed by varying the irradiation conditions. The Raman spectrum shows in the illuminated regions the insurgence of Raman modes, which are forbidden in the used-scattering geometry. This phenomenon increases gradually by approaching the ablation region, where nobium oxides and Li-deficient surfaces are formed for the low energy and high repetition rate pulses from the Ti:Sapphire oscillator. Amorphous surfaces are obtained for high energy and low repetition rate pulses from the amplified Ti:Sapphire laser system. (c) 2005 Elsevier B.V. All rights reserved
Femtosecond Laser Writing of Surface Microstructures in Lithium Niobate
No full textFemtosecond pulses from an amplified Ti:Sapphire laser were found to be a surgically precise manufacturing tool for the formation of microstructures in Lithium Niobate crystals. Surface gratings were formed with 10% first order diffraction efficiency
Ablation of Lithium Niobate through femtosecond nonlinear absorption
No full textFemtosecond laser processing is a promising alternative technique for manufacturing photonic elements such as gratings, micro-holes, and microchannels in different type of transparent materials. The effect of the irradiation of commercial Lithium Niobate substrates with a Ti-Sapphire oscillator with repetition rate 82 Mhz, energy per pulse 20 nJ, pulse duration of 130 fs and an amplified Ti-Sapphire laser system with repetition rate 1 kHz, energy per pulse 1 mJ, and pulse duration of about 130 fs are compared. The investigation of microstructural modifications induced by femtosecond irradiation through optical microscopy and micro-Raman spectroscopy is reported
Optical and structural modification induced in LiNbO3 by femtosecond laser irradiation
No full textMicrometer-size structural modifications are induced in Lithium Niobate through femtoseconod laser irradiation and analysed by mean of confocal Raman spectroscop
Structural and optical defects in LiNbO3 crystals induced by femtosecond laser irradiation
No full textMicrostructural modifications, induced by femtosecond laser irradiation on Lithium Niobate (LN) crystals were investigated by means of optical microscopy and micro-Raman spectroscopy. Commercial z-cut congruent LN substrates were irradiated with focused ultra-short laser pulses at 810 nm. At the focus region either structural changes or material removal were observed by varying the irradiation conditions. The mapping of Raman spectrum revealed the insurgence of Raman modes, which are forbidden in the used scattering geometry. This phenomenon increases gradually by approaching the ablation region
Optically induced ultrafast quenching of the semiconductor quantum well luminescence
No full textWe present an experimental configuration that enables the ultrafast, transient quenching of the excitonic photoluminescence in quantum wells. Our scheme is based on two, delayed, short pulses experiment. A first pulse excites carriers in the system, while a second pulse induces an ultrafast redistribution of excitons that results in abrupt dips in the photoluminescence. We present a model that quantitatively accounts for the measured dip depth. The magnitude of the dip, determined by the temperature change of the carriers, can be controlled by varying the power and delay of the second pulse
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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