Search results for "PUMP"
showing 10 items of 471 documents
Interpretation of negative birefringence observed in strong-field optical pump-probe experiments: High-order Kerr and plasma grating effects
2013
The analysis of negative birefringence optically induced in major air components (Loriot et al., [1, 2]) is revisited in light of the recently reported plasma grating-induced phase-shift effect predicted for strong field pump-probe experiments (Wahlstrand and Milchberg, [3]). The nonlinear birefrin- gence induced by a short and intense laser pulse in argon is measured by femtosecond time-resolved polarimetry. The experiments are performed with degenerate colors, where the pump and probe beam share the same spectrum, or with two different colors and non-overlapping spectra. The in- terpretation of the experimental results is substantiated using a numerical 3D+1 model accounting for nonlinear…
Exploiting transport properties for the detection of optical pumping in heavy ions
2020
We present a kinetic model for optical pumping in Lu$^+$ and Lr$^+$ ions as well as a theoretical approach to calculate the transport properties of Lu$^+$ in its ground $^1S_0$ and metastable $^3D_1$ states in helium background gas. Calculations of the initial ion state populations, the field and temperature dependence of the mobilities and diffusion coefficients, and the ion arrival time distributions demonstrate that the ground- and metastable-state ions can be collected and discriminated efficiently under realistic macroscopic conditions.
Simulations of continuous-wave sodium laser guide stars with polarization modulation at Larmor frequency
2018
The return flux from a sodium laser guide star suffers, at large angles between the geomagnetic field and the laser beam, from the reduction in optical pumping due to spin-precession of sodium atoms. This detrimental effect can be mitigated by modulating the circular polarization of a continuous-wave laser beam in resonance with the Larmor frequency of sodium atoms in the mesosphere. We present an investigation based on numerical modeling to evaluate the brightness enhancement of a laser guide star with polarization modulation of a continuous-wave laser beam at different observatories.
Light-by-light polarization control for telecommunication applications
2010
In this work, we report for the first time the experimental achievement of an all-fibered polarization attraction, which can occur in optical fibers at telecommunication wavelengths. More precisely, we have experimentally shown that is possible to all-optically control and stabilize the state of polarization of a 10 Gbit/s telecommunication signal through the injection of a counter-propagating control pump wave. Eye diagrams recordings and bit error rate measurements have shown that this new type of all-optical function, almost lossless and instantaneous has a promising potential for telecommunication applications.
Nuclear orientation of radon isotopes by spin exchange optical pumping
1988
This paper reports the first demonstration of nuclear orientation of radon atoms. The method employed was spin exchange with potassium atoms polarized by optical pumping. The radon isotopes were produced at the ISOLDE isotope separator of CERN. The nuclear alignment of /sup 209/Rn and /sup 223/Rn has been measured by observation of ..gamma..-ray anisotropies and the magnetic dipole moment for /sup 209/Rn has been measured by the nuclear-magnetic-resonance method to be chemically bond..mu..chemically bond = 0.838 81(39)..mu../sub N/.
Hyperfine and Isotope Shift Measurements Far off Stability by Optical Pumping
1977
In this talk I will review optical pumping (OP) experiments performed by our group to ISOLDE, CERN, in a series of Hg isotopes spanning from mass number 181 to 205 (first results in refs. [1] and [2], final in refs. [3] and [4]. I will then discuss what impact these measurements had on nuclear structure research far off stability and how the results of the latter are retroacting again on the optical work. In particular they ask for isotope shifts (IS) of light even Hg isotopes which we are prepared to measure by laser spectroscopy. Further I would like to communicate briefly first results of optical pumping experiments on “exotic” Rb and Cs isotopes. Finally I will discuss plans for laser s…
Vector Modulational Instabilities and Soliton Experiments
1999
In optical fibers, the interaction between nonlinear and dispersive effects leads to phenomena such as modulational instability (MI)[1, 2, 3, 4, 5, 6], in which a continuous or quasi-continuous wave undergoes a modulation of its amplitude or phase in the presence of noise or any other small perturbation. The perturbation can originate from quantum noise (spontaneous-MI) or from a frequency shifted signal wave (induced-MI). MI has been observed for the first time for a single pump wave propagating in a standard non birefringe.nt fiber (scalar MI)[7]. It has been shown that scalar MI only occurs when the group velocity dispersion (GVD) is negative (anomalous dispersion regime).
Resonance Ionization Laser Ion Source - Off-line tests at TRIUMF
2004
Resonance ionization laser ion sources (RILIS) developed into the most powerful tool for radioactive ion beam production at on-line facilities, as they provide a selective ionization process with inherent suppression of unwanted isobaric contaminations at the ion source. While typical tunable laser systems for these applications are based on dye lasers, we developed an all solid state laser system which consists of three pulsed titanium:sapphire (ti:sa) lasers pumped by a single high repetition rate Nd:YAG laser. Each ti:sa laser provides up to 2.5 W average output power at 12 kHz repetition rate in the wavelength region of 700-950 nm with optional frequency doubling in BBO crystals. This l…
Nuclear Radiation Detected Optical Pumping of neutron-deficient Hg isotopes
1976
The extension of the Nuclear Radiation Detected Optical Pumping method to mass-separated samples of isotopes far off stability is presented for a series of light Hg isotopes produced at the ISOLDE facility at CERN. The isotope under investigation is transferred by an automatic transfer system into the optical pumping apparatus. Zeeman scanning of an isotopically pure Hg spectral lamp is used to reach energetic coincidence with the hyperfine structure components of the 6s 2 1 S 06s6p 3P1,λ=2,537 A resonance line of the investigated isotope and the Hg lamp. The orientation built up by optical pumping is monitored via the asymmetry or anisotropy of the nuclear radiation. Nuclear spins, magneti…
Effects of Scaling in SEE and TID Response of High Density NAND Flash Memories
2010
Heavy ion single-event effect (SEE) measurements and total ionizing dose (TID) response for Micron Technology single-level cell 1, 2, 4, 8 Gb commercial NAND flash memory and multi-level cell 8, 16, 32 Gb are reported. The heavy ion measurements were extended down to LET 0.1 MeV-cm2/mg. Scaling effects in SEE and TID response are discussed. Floating gate bit error upset cross section does not scale with feature size at high LETs, except for single-level cell 8 Gb device which is built with 51 nm processes. The threshold LET does not change with scaling. Charge pump TID degradation and standby current improves with scaling. In general, the effect of radiation is either unchanged or is less s…