Search results for "two-photon excitation"
showing 10 items of 35 documents
Dispersion relation formalism for the two-photon exchange correction to elastic muon-proton scattering: elastic intermediate state
2018
We evaluate the two-photon exchange correction to the unpolarized cross section in the elastic muon-proton scattering within dispersion relations. One of the six independent invariant amplitudes requires a subtraction. We fix the subtraction function to the model estimate of the full two-photon exchange at one of three MUSE beam energies and make a prediction for the two other energies. Additionally, we present single and double polarization observables accounting for the lepton mass.
Absolute frequency measurement of rubidium 5S-7S two-photon transitions.
2013
We report the absolute frequency measurements of rubidium 5S-7S two-photon transitions with a cw laser digitally locked to an atomic transition and referenced to an optical frequency comb. The narrow, two-photon transition, 5S-7S (760 nm) insensitive to first order in a magnetic field, is a promising candidate for frequency reference. The performed tests yield the transition frequency with accuracy better than reported previously.
Collinear two-photon excitation of indium rydberg states in a fast atomic beam
1986
The 29p-Rydberg state of neutral indium was produced by double resonant two-photon excitation in a fast atomic beam and detected via field ionization in a longitudinal electric field.
Two-photon microscopy and neuroinflammation: Crosstalk between T cells and neurons
2014
Dominance of the first excitation step for magnetic circular dichroism in near-threshold two-photon photoemission
2012
Magnetic circular dichroism (MCD) in near-threshold photoemission is measured for a perpendicularly magnetized Cs/Co/Pt(111) film with work function adjusted by Cs adsorption. For one-photon photoe ...
Quasi-isotropic 3-D resolution in two-photon scanning microscopy.
2009
One of the main challenges in three-dimensional microscopy is to overcome the lack of isotropy of the spatial resolution, which results from the axially-elongated shape of the point spread function. Such anisotropy gives rise to images in which significant axially-oriented structures of the sample are not resolved. In this paper we achieve an important improvement in z resolution in two-photon excitation microscopy through spatial modulation of the incident beam. Specifically, we demonstrate that the design and implementation of a simple shaded ring performs quasi-isotropic three-dimensional imaging and that the corresponding loss in luminosity can be easily compensated by most available fe…
Single-shot generation and detection of a two-photon generalized binomial state in a cavity
2006
A "quasi-deterministic" scheme to generate a two-photon generalized binomial state in a single-mode high-Q cavity is proposed. We also suggest a single-shot scheme to measure the generated state based on a probe two-level atom that "reads" the cavity field. The possibility of implementing the schemes is discussed.
Two-photon exchange correction in elastic unpolarized electron-proton scattering at small momentum transfer
2015
We evaluate the two-photon exchange (TPE) correction to the unpolarized elastic electron-proton scattering at small momentum transfer $ Q^2 $. We account for the inelastic intermediate states approximating the double virtual Compton scattering by the unpolarized forward virtual Compton scattering. The unpolarized proton structure functions are used as input for the numerical evaluation of the inelastic contribution. Our calculation reproduces the leading terms in the $ Q^2 $ expansion of the TPE correction and goes beyond this approximation by keeping the full $ Q^2 $ dependence of the proton structure functions. In the range of small momentum transfer, our result is in good agreement with …
Two-photon spectroscopy of mercury and velocity-selective double resonances
2009
Two-photon laser spectroscopy of the $6\text{ }{^{1}S}_{0}\ensuremath{-}7\text{ }{^{1}S}_{0}$ transition in mercury has been performed using two copropagating continuous-wave laser beams. One laser beam is at 254 nm wavelength and can be tuned to the $6\text{ }{^{1}S}_{0}\ensuremath{-}6\text{ }{^{3}P}_{1}$ resonance. The other laser beam is at 408 nm. Two very different regimes can be distinguished, one far off resonance and one near resonance with the one-photon resonance. A resonance which is not Doppler broadened has been observed for low Rabi frequencies. This velocity-selective double resonance in a three-level ladder system is analogous to the dark resonance in three-level $\ensuremat…
Operation conditions and stability of a degenerate two-photon laser
1993
Abstract The presence of a far off-resonant intermediate level in a degenerate three-level two-photon laser model manifests through a steady pump-dependent and a dynamic frequency shift on the laser equations. The steady shift strongly affects the pump threshold necessary for emission, preventing it in certain cases. The dynamic shift makes the frequency pulling/pushing to be intensity-dependent and substantially modify the domains of existence and stability of the lasing solution permitting stable operation for large cavity losses in certain cases.