Search results for " coherence"

Field-free molecular alignment of CO2 mixtures in presence of collisional relaxation

2008

The present work explores the extension of the concept of short-pulse-induced alignment to dissipative environments within quantum mechanical density matrix formalism (Liouville equation) from the weak to the strong field regime. This is illustrated within the example of the CO2 molecule in mixture with Ar and He, at room temperature, for which a steep decrease of the alignment is observed at moderate pressure because of the collisional relaxation. The field-free alignment is measured by a polarization technique where the degree of alignment is monitored in the time domain by measuring the resulting transient birefringence with a probe pulse Raman induced polarization spectroscopy (RIPS) Co…

Atomic Coherence Effects in Doppler-Broadened Three-Level Systems with Standing-Wave Drive

2001

We study atomic coherence effects (e.g., electromagnetically induced transparency, EIT, and amplification without inversion, AWI) for a probe travelling-wave (TW) laser field in closed Doppler-broadened three-level systems driven by a standingwave (SW) laser field of moderate intensity (its Rabi frequencies are smaller than the Doppler width of the driven transition). We show that probe windows of transparency occur only for values of the probe to drive field frequency ratio R close to half integer values. For optical transitions and typical values of Doppler broadening for atoms in a vapor cell, we show that for R > 1 a SW drive field is appreciably more efficient than a TW drive in induci…

Using Partial Coherence and Digital Holography for 3D Imaging and Profile Extraction

2008

Two approaches for 3D imaging are presented. At first we use partial coherence of the light source and in the second we compute the unwrapped phase by illuminating the object from several slightly different angles.

‘Nonlocal’ dispersion cancelation with classical light

2009

We show a classical analog of the original nonlocal dispersion cancelation effect in intensity interferometry with stationary light obeying Gaussian statistics. The dispersion compensation is due to the uncorrelation of the spectral components of the radiation. Although this classical counterpart phenomenon is not nonlocal in a strict quantum mechanical sense, it suggests that some second-order interference devices relying on temporal entanglement do not require a quantum light source.

Transversal superresolution with noncontact axial movement of periodic structures

2007

We present an innovative approach that allows superresolved images to be obtained by axial moving of two gratings and time integrating in the detector plane. The two gratings do not have to be in contact with either the object or the detector, and both are positioned between the object and the image planes. One of the main applications for the proposed approach in contrast to previously discussed time multiplexing superresolving methods is that it may fit well to superresolved imaging of remote objects, since both gratings are not in contact with either the object or the detector planes.

Repeatability of whole-cornea measurements using a new swept-source optical coherence tomographer

2020

Purpose: The aim of this study was to evaluate the repeatability of several corneal parameters provided by a high-resolution swept-source optical coherence tomographer (SS-OCT). Methods: One eye from each of 74 patients was measured five times consequently using the ANTERION SS-OCT. The following corneal parameters were analyzed: average, steep and flat keratometry (K), astigmatism for anterior, posterior and total at 3-mm, average K and astigmatism at 6-mm, anterior and posterior eccentricity, higher-order aberrations (HOA) and spherical aberration ([Formula: see text]), and anterior and posterior best-fit sphere at 8-mm. The intrasubject standard deviation (Sw), coefficient of variation (…

2019

We demonstrate experimentally ghost optical coherence tomography using a broadband incoherent supercontinuum light source with shot-to-shot random spectral fluctuations. The technique is based on ghost imaging in the spectral domain where the object is the spectral interference pattern generated from an optical coherence tomography interferometer in which a physical sample is placed. The axial profile of the sample is obtained from the Fourier transform of the correlation between the spectrally resolved intensity fluctuations of the supercontinuum and the integrated signal measured at the output of the interferometer. The results are in excellent agreement with measurements obtained from a …

Correlation of Crystallin Expression and RGC Susceptibility in Experimental Glaucoma Rats of Different Ages.

2018

Glaucoma is one of the leading causes of blindness worldwide with age being an important risk factor. However, the pathogenesis remains poorly understood. Aim of this study was to focus on age-dependent molecular changes in an experimental animal model of glaucoma.Intraocular pressure was elevated in Sprague-Dawley rats aged 3, 14, and 47 weeks for a period of 7 weeks by episcleral vein cauterization. Ganglion cell loss was monitored by an immunohistochemical staining of the Brain-specific homeobox/POU (Pit-1, Oct-2, Unc-86) domain protein 3A positive cells in retinal flat-mounts and spectral-domain optical coherence tomography measuring the retinal nerve fiber layer thickness. Molecular pr…

Psychometrische Evaluation und Normwerte einer Ultrakurzform der Sense of Coherence Scale “SOC-3”

2019

ZusammenfassungKohärenzsinn ist eine psychische Ressource, die maßgeblich zu einem adaptiven Coping im Umgang mit belastenden Situationen beiträgt. In der vorliegenden Studie untersuchen wir eine Ultrakurzform der Sense of Coherence Scale (SOC-3) in einer repräsentativen Stichprobe der deutschen Bevölkerung (N=2.018). Das 3-Item-Modell wies exzellente Gütekriterien sowie eine akzeptable Reliabilität auf. Über Altersgruppen und Geschlecht konnte partielle strikte Messinvarianz des Modells nachgewiesen werden. In Bezug auf Konstruktvalidität demonstrierten unsere Analysen starke Überschneidungen der SOC-3 mit längeren SOC-Versionen (−9 und−29). Analog zu den SOC-Langversionen wurden erwartung…

Fear of COVID-19 and Life Satisfaction: The Role of the Health-Related Hardiness and Sense of Coherence

2021

Introduction: The COVID-19 pandemic is contributing to increased fear and anxiety throughout society, which may affect life satisfaction. Health-related hardiness and sense of coherence (SOC) are personal resources that help people adapt to difficult circumstances. The purpose of this study was to investigate the relationship between fear of COVID-19, SOC, health-related hardiness, and life satisfaction.Methods: A total of 907 Polish people (522 women and 385 men) participated in this study. The Fear of COVID-19 Scale (FOC-6), the Health-Related Hardiness Scale, the Sense of Coherence Scale (SOC-29), and the Satisfaction with Life Scale were used.Results: Correlation showed that fear of COV…