Search results for "Width"
showing 10 items of 690 documents
Two-photon widths of theχc0,2states and helicity analysis forχc2→γγ
2012
Based on a data sample of 106 X 10(6) psi' events collected with the BESIII detector, the decays psi' -> gamma chi(c0,2), chi(c0,2) -> gamma gamma are studied to determine the two-photon widths of the chi(c0,2) states. The two-photon decay branching fractions are determined to be B(chi(c0) -> gamma gamma) = (2.24 +/- 0.19 +/- 0.12 +/- 0.08) X 10(-4) and B(chi(c2) -> gamma gamma) = (3.21 +/- 0.18 +/- 0.17 +/- 0.13) X 10(-4) From these, the two-photon widths are determined to be Gamma(gamma gamma)(chi(c0)) = (2.33 +/- 0.20 +/- 0.13 +/- 0.17) keV, Gamma(gamma gamma)(chi(c2)) = (0.63 +/- 0.04 +/- 0.04 +/- 0.04) keV, and R = Gamma(gamma gamma)(chi(c2))/Gamma(gamma gamma)(chi(c0)) = 0.271 +/- 0.0…
Incoherent photonic techniques for RF-AWG
2010
The capabilities for RF-AWG in terms of waveform fidelity for three different incoherent photonic methods are revised and discussed: incoherent frequency-to-time mapping, incoherent MWP filtering with N discrete taps, and multi-wavelength pulse compression.
Radiating and nonradiating behavior of hyperbolic-secant, raised-cosine, and Gaussian input light pulses in dispersion-managed fiber systems.
2005
We address the problem of optical light pulses, called dressed pulses, which do not match the stationary pulse profile of a dispersion-managed (DM) fiber system and we theoretically analyze the associated radiation. Comparing hyperbolic-secant, raised-cosine, and Gaussian pulse envelopes, we show that the general radiation figure is highly sensitive to the input pulse profile. As common general features for these pulse profiles, we find a rich variety of dynamical states that includes weak-, moderate-, and strong-radiation states, depending on the map strength of the DM fiber system. We demonstrate the existence of two intervals of map strengths where the emitted radiation is of considerabl…
Rogue wave statistics from a noise-like-pulse laser
2014
We report on experimental conditions in a fiber ring laser where noise-like pulse emission fulfills the rogue wave criteria. We highlight the role of dispersion, and use the dispersive Fourier-transform method to study spectral fluctuations.
Triply resonant coherent four-wave mixing in silicon nitride microresonators
2015
The generation of multiple tones using four-wave mixing (FWM) has been exploited for many applications, ranging from wavelength conversion to frequency comb generation. FWM is a coherent process, meaning that its dynamics strongly depends on the relative phase among the waves involved. The coherent nature of FWM has been exploited for phase-sensitive processing in different waveguide structures, but it has never been studied in integrated microresonators. Waveguides arranged in a resonant way allow for an effective increase in the wavelength conversion efficiency (at the expense of a reduction in the operational bandwidth). In this letter, we show that phase shaping of a three-wave pump pro…
Experimental validation of a novel compact focusing scheme for future energy-frontier linear lepton colliders.
2014
A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [ P. Raimondi and A. Seryi , Phys. Rev. Lett. 86 , 3779 ( 2001 ) ]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.
Resonant Rayleigh scattering in quantum well structures
1996
Abstract We report continuous wave experiments on resonant Rayleigh scattering (RRS) performed on high quality GaAs AlGaAs quantum well structures. The simultaneous measurement of the resonant Rayleigh scattering and of the photoluminescence excitation (PLE) allows us to resolve very small differences between the two spectra. We show that, even in very good samples, there is a small but detectable Stokes shift of the RRS profile with respect to the PLE. It is also found that the RRS profile has a smaller linewidth and is sensitive to bound exciton transitions which are not detectable in the PLE. We compare our data with previous findings and discuss possible origins of the Stokes shift.
Exciton fine structure splitting of single InGaAs self-assembled quantum dots
2004
Abstract We show how the resonant absorption of the ground state neutral exciton confined in a single InGaAs self-assembled quantum dot can be directly observed in an optical transmission experiment. A spectrum of the differential transmitted intensity is obtained by sweeping the exciton energy into resonance with laser photons exploiting the voltage induced Stark-shift. We describe the details of this experimental technique and some example results which exploit the ∼1 μeV spectral resolution. In addition to the fine structure splitting of the neutral exciton and an upper bound on the homogeneous linewidth at 4.2 K , we also determine the transition electric dipole moment.
How narrow is the linewidth of parametric X-ray radiation?
1997
Parametric x-ray or quasi-Cherenkov radiation is produced by the passage of an electron through a crystal. A critical absorber technique has been employed to investigate its linewidth. Experiments have been performed with the 855MeV electron beam from the Mainz Microtron MAMI. Thin absorber foils were mounted in front of a CCD camera serving as a position sensitive photon detector. Upper limits of the linewidth of 1.2 and 3.5eV were determined for the (111) and (022) reflections of silicon at photon energies of 4966 and 8332eV. These limits originate from geometrical line broadening effects that can be optimized to reach the ultimate limit given by the finite length of the wave train. {copy…
High-resolution positron lifetime spectrometer with BaF2 scintillators
1987
In this communication we report on a design of a fast coincidence positron lifetime spectrometer, which is based on single crystal barium fluoride (BaF2) scintillators. A good time resolution (190ps, FWHM), combined with a high efficiency, has been obtained in the normal experimental set-up (with cathode earthed in the photo multipliers). The pile-up effect is observed to disturbe the measured lifetimes in the 180 degree geometry due to the high detection efficiency of the BaF2 scintillator.