Search results for "OPTICS"
showing 10 items of 10033 documents
The CCSD(T) model with Cholesky decomposition of orbital energy denominators
2010
A new implementation of the coupled cluster singles and doubles with approximate triples correction method [CCSD(T)] using Cholesky decomposition of the orbital energy denominators is described. The new algorithm reduces the scaling of CCSD(T) from N-7 to N-6, where N is the number of orbitals. The Cholesky decomposition is carried out using simple analytical expressions that allow us to evaluate a priori the order in which the decomposition should be carried out and to obtain the relevant parts of the vectors whenever needed in the calculation. Several benchmarks have been carried out comparing the performance of the conventional and Cholesky CCSD(T) implementations. The Cholesky implement…
Modifications of high harmonic spectra by ion resonant transitions
1996
High-order harmonic generation is considered in a system consisting of an ion with an internal degree of freedom plus an outer electron. The theoretical treatment is both quantum-mechanical and classical. The emphasis is on the core resonance effects, which can significantly modify the harmonic spectra, with appearance of anomalous peaks. Under some assumptions, the spectral amplitude of the resonant harmonic of the system dipole moment can be obtained by evaluation of such amplitude within a single-electron approximation and multiplication of the result by a correcting factor. The latter depends on the polarizability of the ion and of a free electron at the harmonic frequency. Copyright © …
Training Schrödinger’s cat: quantum optimal control
2015
It is control that turns scientific knowledge into useful technology: in physics and engineering itprovides a systematic way for driving a dynamical system from a given initial state into a desired targetstate with minimized expenditure of energy and resources. As one of the cornerstones for enabling quantumtechnologies, optimal quantum control keeps evolving and expanding into areas as diverse as quantumenhancedsensing, manipulation of single spins, photons, or atoms, optical spectroscopy, photochemistry,magnetic resonance (spectroscopy as well as medical imaging), quantum information processing and quantumsimulation. In this communication, state-of-the-art quantum control techniques are r…
FT Raman and DFT Study on a Series of All-antiOligothienoacenes End-Capped with Triisopropylsilyl Groups
2009
minal a positions. These substituents aid in purification and solution processability, and can be removed under mild chemical conditions. For the first time, we have the opportunity to analyze a series of oligothienoacenes to gain insight into the fundamental structure–property relationships with respect to the addition of each ring. Furthermore, this series of compounds can be directly compared to other well-studied series of closely related oligomers, such as nonfused oligothiophenes and fully fused all-syn oligothienoacenes. [7] To gain precise insight into relationships between the structure and properties of a wide range of p-conjugated molecular Herein, we study the p-conjugational pr…
Study of the use of methanol-filled Er-doped suspended-core fibres in a temperature-sensing ring laser system
2013
We report on an experimental/numerical investigation into the use of methanol-filled Er-doped suspended-core fibres (SCFs) in temperature-sensing ring laser systems. We have adopted a ring laser configuration that includes an Er-doped SCF as a temperature-dependent attenuator (TDA) with a step-index Er-doped fibre (EDF) as the laser active medium. The laser performance dependence on the temperature was measured both in continuous wave (CW) and transient regimes. CW laser output power and build-up time values are compared with those of similar laser systems based on other types of Er-doped PCFs or using other laser configurations. A notable variation of 0.73% °C−1 was achieved in CW operatio…
Artifacts and Errors in Cross-Spectrum Phase Noise Measurements : Invited lecture
2021
Inserting an attenuator between the oscillator under test and the phase noise analyzer, one expects that the white phase noise increases monotonically with the attenuation. By contrast, we observe that with some oscillators the white noise has sharp minimum for a given value of the attenuation, which clearly indicates problem. With other oscillators, it increases monotonically with the attenuation, but the values are not consistent with the thermal energy introduced by the attenuator. In both cases artifacts are present, which takes the form of a sharp notch in the spectrum, occurring where the white FM noise crosses the white PM noise. Such anomalous behavior is the tip of the iceberg, and…
Genre-dependent effects of 3D film on presence, motion sickness, and protagonist perception
2016
Do the increasingly popular 3D movies change how we perceive the content of the movie? We presented short (3.21 min) film sequences to observers equipped with shutter glasses. Three genres (horror, action, and documentary) were crossed with three between-subjects viewing conditions (director’s 3D, artificial 3D, and 2D). Observers had to rate how the film impressed them in terms of arousal, motion sickness, presence, and immersion. They also judged the personality, attractiveness, and intelligence of the protagonist in all viewing conditions. Not surprisingly, horror films produced more arousal and presence than action films. Documentaries scored lowest on presence. Action movies produced t…
Diamond nucleation on iridium: local variations of structure and density within the BEN layer
2009
Abstract The diamond nuclei generated by the bias enhanced nucleation (BEN) on iridium are gathered in well defined areas (“domains”). In atomic force microscopy (AFM) measurements they become manifest in a 1 nm downward step. The fine structure of the carbon layer inside and outside these domains has been studied by small spot Auger electron spectroscopy (AES), high resolution transmission electron microscopy (HRTEM), AFM and lateral force microscopy (LFM). The Auger spectra of the carbon KLL peak taken in an ultra high vacuum setup revealed diamond features inside and more graphitic features outside the domains. The comparison with the intensity of the Auger signal originating from the un…
From the Paper to the Tablet: On the Design of an AR-Based Tool for the Inspection of Pre-Fab Buildings. Preliminary Results of the SIRAE Project
2018
Energy-efficient Buildings (EeB) are demanded in today’s constructions, fulfilling the requirements for green cities. Pre-fab buildings, which are modularly fully-built in factories, are a good example of this. Although this kind of building is quite new, the in situ inspection is documented using traditional tools, mainly based on paper annotations. Thus, the inspection process is not taking advantage of new technologies. In this paper, we present the preliminary results of the SIRAE project that aims to provide an Augmented Reality (AR) tool that can seamlessly aid in the regular processes of pre-fab building inspections to detect and eliminate the possible existing quality and ener…
Optical security and encryption with totally incoherent light
2001
We present a method for securing and encrypting information optically by use of totally incoherent illumination. Encryption is performed with a multichannel optical processor working under natural (both temporal and spatially incoherent) light. In this way, the information that is to be secured can be codified by use of color signals and self-luminous displays. The encryption key is a phase-only mask, providing high security from counterfeiting. Output encrypted information is recorded as an intensity image that can be easily stored and transmitted optically or electrically. Decryption or authentication can also be performed optically or digitally. Experimental results are presented.