Search results for "intensity"
showing 10 items of 1091 documents
Statistical Signatures of Nanoflare Activity. I. Monte Carlo Simulations and Parameter-space Exploration
2019
Small-scale magnetic reconnection processes, in the form of nanoflares, have become increasingly hypothesized as important mechanisms for the heating of the solar atmosphere, for driving propagating disturbances along magnetic field lines in the Sun's corona, and for instigating rapid jet-like bursts in the chromosphere. Unfortunately, the relatively weak signatures associated with nanoflares places them below the sensitivities of current observational instrumentation. Here, we employ Monte Carlo techniques to synthesize realistic nanoflare intensity time series from a dense grid of power-law indices and decay timescales. Employing statistical techniques, which examine the modeled intensity…
Fourier-transform spectroscopy, direct potential fit, and electronic structure calculations on the entirely perturbed (4) 1Π state of RbCs
2018
We perform a high-resolution Fourier-transform spectroscopic study of the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}$ state of the RbCs molecule by applying two-step $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}\ensuremath{\leftarrow}A{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}\ensuremath{\sim}b{\phantom{\rule{0.16em}{0ex}}}^{3}\mathrm{\ensuremath{\Pi}}\ensuremath{\leftarrow}X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ optical excitation followed by observation of the $(4){\phantom{\rule{0.16em}{0ex}}}^{1}\mathrm{\ensuremath{\Pi}}\ensuremath{\rightarrow}X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensu…
Wave propagation in optical systems
1974
The intensity distribution in the image space of an optical system, due to an arbitrary object, is calculated by solving the problem of the propagation of a monochromatic light wave through the system. The system is assumed to be cylindrically symmetric with an arbitrary number of spherical surfaces. Analytic techniques based on the principle of stationary phase are used, and several advantages over ray-tracing techniques are obtained.
Incoherent frequency-to-time mapping: application to incoherent pulse shaping
2007
After temporal amplitude modulation of a spectrally incoherent optical source the averaged intensity profile at the so-called temporal far-zone regime coalesces with a magnified replica of the spectral density function of the source. This has provided the basis for the generalization of the frequency-to-time mapping technique in the partially coherent case. Based on this fact, temporal intensity waveform generation is demonstrated by spectral filtering the incoherent source before the temporal modulation stage. We refer to this technique as full incoherent pulse shaping. Although only the average intensity of the output signal is properly shaped, intensity fluctuations between the different…
Unraveling of an original mechanism of hypometria in human using a new myohaptic device — The Wristalyzer
2009
We report a novel form of hypometria in a patient presenting a spinocerebellar ataxia type 2 (SCA2; 32 repeats; Age: 44). We investigated fast pointing (FP) and fast reversal (FR) single-joint movements performed under artificial damping conditions using our myohaptic device called Wristalyzer, which allows an instantaneous regulation of the mechanical characteristics of a wrist manipulandum. The wristalyzer controller has a range of motion from −1 rad to +1 rad. The inertia of the motor/handgrip is 0.004 kg × m2. Movements were studied in free mode and with damping either at 0.1 Nms/rad or 0.2 Nms/rad. Subjects performed sets of FP movements and FR movements over 3 distances (targets: 0.2,…
Dynamic Stark effect action on optical pumping of atoms in an external magnetic field
1992
Abstract The influence of the dynamic Stark effect on the optical pumping of atoms in a magnetic field, using the broad band approximation, is examined. It is demonstrated that the dynamic Stark effect can lead to a nonlinear effect on the light intensity conversion of alignment produced by linearly polarized light in the orientation of the angular momentum of atoms.
Evidence for degenerate mirrorless lasing in alkali metal vapor: forward beam magneto-optical experiment
2018
We report an experimental observation of degenerate mirrorless lasing in forward direction under excitation of a dilute atomic Rb vapor with a single linearly polarized cw laser light resonant with cycling Fe > Fg atomic D2 transitions. Light polarized orthogonally to the laser light is generated for the input light intensity exceeding a threshold value of about 3 mW/cm^2. Application of a transverse magnetic field directed along the input light polarization reveals a sharp about 20 mG wide magnetic resonance centered at B = 0. Increasing the incident light intensity from 3 to 300 mW/cm^2, the generated light undergoes rapid amplitude increase followed by a decline and resonance broadeni…
Absorbing anisotropic and gyrotropic slab between crossed polarizers in parallel light
1980
When a birefringent slab is rotated between two crossed polarizers, the four maxima and four minima of the transmitted intensity occur, as known, at every π/4 radians. If the slab is also optically active, the maxima and minima are arranged in other patterns that may be grouped according to the number of extrema met in one complete turn of the slab: four or eight. All the possible patterns are classified and each is related to some peculiarity of the complex refractive index of the slab.
Multivalued solutions for the output intensity of a semilinear photorefractive oscillator and stability analysis
2007
The analysis of pump-ratio dependences of the output intensity for a semilinear photorefractive coherent oscillator reveals two domains of multivalued solutions for sufficiently large coupling strength ensured by the crystal. We show that even in a strictly degenerate case the nonzero output intensity can be reached in a broad range of pump ratios r from 10−6 to infinity, including the interval where both pump intensities coincide or are very close to each other. This does not contradict the existence of the known gap in the oscillation threshold near the equal intensities of two pump waves: in this particular region the oscillation is not self-starting. The output intensities for frequency…
Modeling of the photorefractive nonlinear response in Sn_2P_2S_6 crystals
2007
We develop a theory of the photorefractive nonlinear response for Sn2P2S6 crystals. The theory incorporates two types of charge carrier (optically active and passive), provides explicit expressions for the characteristic buildup-relaxation rates and gain factors, explains naturally a big variety of accumulated experimental data, and facilitates characterization-optimization of this important nonlinear material.