Search results for "intensity"
showing 10 items of 1091 documents
Coherent light scattering on nanofluids: computer simulation results.
2008
If coherent light is incident on a suspension containing nanoparticles, they act as scattering centers and the result of the far-field interference is a "speckled" image. The scattering centers have a complex movement of both sedimentation and Brownian motion. Consequently the speckle image is not static but presents time fluctuations. A computer code to simulate the dynamics of the coherent light scattering on nanofluids was written, tested, and used to calculate the far-field intensity variation for nanofluids having different particle size. The results are discussed and an alternative experimental method for fast nanoparticle size assessing is suggested as a possible application.
Intensity-Based Single Particle Plasmon Sensing.
2021
Plasmon sensors respond to local changes of their surrounding environment with a shift in their resonance wavelength. This response is usually detected by measuring light scattering spectra to determine the resonance wavelength. However, single wavelength detection has become increasingly important because it simplifies the setup, increases speed, and improves statistics. Therefore, we investigated theoretically how the sensitivity toward such single wavelength scattering intensity changes depend on the material and shape of the plasmonic sensor. Surprisingly, simple equations describe this intensity sensitivity very accurately and allow us to distinguish the various contributions: Rayleigh…
Generation of isolated attosecond pulses using unipolar and laser fields
2009
A new scheme to generate isolated attosecond pulses is presented that involves the use of a laser field and of a unipolar field. The laser field has a pulse of intensity I = 1.5×1014 W cm−2 and wavelength λ = 820 nm. The unipolar pulse is an asymmetric pulse consisting of a sharp peak, lasting approximately half a laser period, i.e. nearly 1.4 fs, followed by a long and shallow tail. We show that on combining these two fields, it is possible to generate isolated attosecond pulses as short as 1/10 of a laser period, i.e. approximately 270 as. Moreover, it is argued that this scheme is robust either against small variations of the laser envelope, or against small changes in the delay between …
Slowdown and speedup of light pulses using the self-compensating photorefractive response
2011
We study theoretically the effects of pulse slowdown and speedup in ferroelectric Sn2P2S6 possessing a self-compensating photorefractive response. It is shown that both these effects can be implemented in one sample for sufficiently large values of the coupling strength. In contrast to other types of the photorefractive response (local and nonlocal), the output pulses do not suffer from strong spatial amplification and broadening.
Test of band structure calculations for Heusler compounds by spin-resolved photoemission spectroscopy
2012
The electronic density of states of epitaxial thin films of the Heusler compound Co${}_{2}$MnGa is probed in situ by spin-resolved ultraviolet photoemission spectroscopy. The experiments reveal several characteristic features in the intensity spectrum and a clear Fermi edge signature. A high spin polarization of $\ensuremath{\simeq}\phantom{\rule{-0.16em}{0ex}}55%$ at the Fermi edge is followed by a sign change at the binding energy of $\ensuremath{\simeq}$0.8 eV. Corresponding calculations of the band structure and the photoemission spectrum were performed employing a spin-polarized relativistic Korringa-Kohn-Rostoker code. Good agreement between the experimental data and calculations was …
Enhancement of stability in randomly switching potential with metastable state
2004
The overdamped motion of a Brownian particle in randomly switching piece-wise metastable linear potential shows noise enhanced stability (NES): the noise stabilizes the metastable system and the system remains in this state for a longer time than in the absence of white noise. The mean first passage time (MFPT) has a maximum at a finite value of white noise intensity. The analytical expression of MFPT in terms of the white noise intensity, the parameters of the potential barrier, and of the dichotomous noise is derived. The conditions for the NES phenomenon and the parameter region where the effect can be observed are obtained. The mean first passage time behaviours as a function of the mea…
Corrigendum to “Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2h top data system” [J. Quant.…
2017
Abstract This corrigendum provides a new version of one of the 3 supplementary data files associated with the article A. Alkadrou et al., J. Quant. Spectrosc. Radiat. Transf. 182 (2016) 158–171, namely the HITRAN-formatted linelist generated as described in section 5 of the article. Indeed, the K a and K c labels of the upper levels of a number of transitions belonging to the ν 10 , ν 7 and ν 4 bands listed in this supplementary data file were found to be incorrect. The linelist provided with this corrigendum corrects these erroneous assignments, and provides K a and K c labels for all the upper levels.
SU-E-T-343: Valencia Applicator Commissioning Using a Micro-Chamber Array
2014
Purpose: In the commissioning and QA of surface isotope-based applicators, source-indexer distance (SID) has a great influence in the flatness, symmetry and output. To these purposes, methods described in the literature are the use of a special insert at the entrance of dwell chamber or radiochromic films. Here we present the experience with a micro-chamber array to perform the commissioning and QA of Valencia applicators. Methods: Valencia applicators have been used, the classic and the new extra-shielded version. A micro-chamber array has been employed, 1000 SRS (PTW), with 977 liquid filled, 2.3×2.3×0.5 mm3 sized ion chambers covering 11×11 cm2, which spacing is 2.5 mm in the central 5.5…
Opto-digital tomographic reconstruction of the Wigner distribution function of complex fields.
2008
An optical-digital method has been developed to obtain the Wigner distribution function of one-dimensional complex fields. In this technique an optical setup is employed to experimentally achieve the Radon-Wigner spectrum of the original signal through intensity measurements. Digital tomographic reconstruction is applied to the experimental spectrum to reconstruct the two-dimensional Wigner distribution function of the input. The validity of our proposal is demonstrated with experimental data, and the results are compared with computer simulations.
Imaging of test quartz gratings with a photon scanning tunneling microscope Experiment and theory
1995
We use the differential formalism of the electromagnetic theory of gratings to interpret the images of test sinusoidal or lamellar quartz gratings obtained with a photon scanning tunneling microscope. The period of the grating is 0.5 μm, and the height of the rule is 0.2 μm. It is shown that the images depend strongly on several parameters, such as polarization or angle of incidence, with respect to the ruling direction. A systematic study of the isointensity lines above the gratings as a function of polarization is presented, and it is shown that the image contrast can be increased or decreased depending on the sample–probe distance. To model the interaction of the fiber probe with the ele…