Electron superelastic scattering from states of atomic sodium and rubidium

1996 ◽  
Vol 74 (11-12) ◽  
pp. 977-983 ◽  
Author(s):  
B. V. Hall ◽  
R. T. Sang ◽  
M. Shurgalin ◽  
W. R. MacGillivray ◽  
M. C. Standage ◽  
...  
Keyword(s):  
Quantum Electrodynamics ◽  
Optical Pumping ◽  
Optical Excitation ◽  
Ground Level ◽  
Excitation Process ◽  
Atomic Sodium ◽  
Laser Modes ◽  
Superelastic Scattering ◽  
Nonzero Spin ◽  
Full Quantum

This paper reports on the extension of the electron superelastic scattering technique to three new situations. The first considers scattering from the 32P3/2 level of Na that has been excited by two laser modes tuned, respectively, to the transitions from the two hyperfine states of the 32S1/2 ground level. Both coherent and noncoherent modes are treated in a full quantum electrodynamic model of the laser excitation. Under certain conditions, the time-averaged probability of finding an atom in the 32P3/2 level exceeds 0.5. The second situation is electron superelastic scattering from the 32D5/2 level of Na that has been resonantly excited from the ground level via a resonant intermediate level. With the first observation of superelastically scattered electrons from this higher lying level recently recorded, this paper considers the extension of the quantum electrodynamics (QED) model to describe the optical excitation process. Application of superelastic scattering to the 52S1/2–52P3/2 transition of Rb is the third situation considered. The superelastic scattering formalism is extended to allow for a nonzero spin flip cross section for this transition. The resulting optical pumping terms are calculated using the QED model and the method of their determination for the superelastic scattering experiment described. The experimental design necessary to measure all of the collision parameters for this transition is discussed.

LIGHT EMISSION, ABSORPTION AND AMPLIFICATION IN InAs/GaAs QUANTUM DOTS AND GaAs/AlGaAs QUANTUM WELLS RESULTING FROM OPTICAL PUMPING

2007 ◽  
Vol 06 (03n04) ◽  
pp. 241-244 ◽  
Author(s):  
D. A. FIRSOV ◽  
L. E. VOROBJEV ◽  
M. A. BARZILOVICH ◽  
V. YU. PANEVIN ◽  
I. V. MIKHAYLOV ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Wells ◽  
Light Absorption ◽  
Optical Pumping ◽  
Light Emission ◽  
Optical Excitation ◽  
Ground Level ◽  
Infrared Light ◽  
Mid Infrared ◽  
Gaas Quantum Dot

Optical phenomena in quantum dot and quantum well nanostructures aimed at the development of mid-infrared lasers based on intraband electron transitions are investigated in the conditions of interband optical pumping. Evolution of photoluminescence spectra and interband light absorption with intensity of interband optical excitation is investigated in InAs / GaAs quantum dot structures. Optically induced intersubband mid-infrared light absorption is studied in undoped tunnel-coupled GaAs / AlGaAs quantum wells. The stabilization of the electron concentration at the ground level of tunnel-coupled quantum wells under increasing pumping level is established.

scholarly journals New Data from Laser Interrogation of Electron-Atom Collisions Experiments

1996 ◽  
Vol 49 (2) ◽  
pp. 499
Author(s):  
AT Masters ◽  
RT Sang ◽  
WR MacGillivray ◽  
MC Standage
Keyword(s):  
Laser Radiation ◽  
Optical Pumping ◽  
Single Mode ◽  
Ground Level ◽  
Stokes Parameters ◽  
Scattered Electron ◽  
Electron Atom ◽  
Level Data ◽  
Superelastic Scattering ◽  
Upper Level

Recent data from two methods in which high resolution laser radiation is used to assist in determining electron-atom collision parameters are presented. The electron superelastic method has yielded the first measurement of Stokes parameters for electron de-excitation of the 32D5/2–32P3/2,1/2 transition of atomic Na, the upper level having been optically prepared by resonant, stepwise excitation from the 32S1/2 ground level via the 32P3/2 level using two single mode lasers. As well, we report on the development of a model to determine the optical pumping parameters for superelastic scattering from the 32P3/2 level when it is prepared by two lasers exciting from the F = 1 and F = 2 states respectively of the 32S1/ 2 ground level. Data are also presented for collision parameters for the excitation of the 61So–61 PI transition of the I = 0 isotope of Hg by electrons of 50 eV incident energy. The technique employed for these measurements is the stepwise electron–laser excitation coincidence method, in which the electron excited atom is further excited by resonant laser radiation, and fluorescence photons emitted by relaxation from the laser excited state are detected in coincidence with the scattered electron.

scholarly journals Laser Assisted Collisions of Electrons with Metal Vapours

1996 ◽  
Vol 49 (2) ◽  
pp. 481 ◽  
Author(s):  
PJO Teubner ◽  
PM Farrell ◽  
V Karaganov ◽  
MR Law ◽  
V Suvorov
Keyword(s):  
Electron Scattering ◽  
Cross Sections ◽  
Ground State ◽  
Optical Pumping ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Kinematic Range ◽  
Excitation Process ◽  
Metal Vapour ◽  
Superelastic Scattering

Three separate experiments are described which use laser radiation to probe the details of electron scattering processes from metal vapour targets. Results from superelastic scattering experiments from calcium are presented. The experiments were carried out at incident energies of 25�7 and 45 eV referred to the ground state. Scattering amplitudes derived from these experiments demonstrate that current theories are inadequate. The coherence of the excitation process has been studied by measuring the total polarisation. It is shown that the excitation process is coherent over the whole kinematic range. Preliminary results from a study of superelastic electron scattering from lithium are discussed where it is shown that a quantum electrodynamical model can be used to describe the optical pumping process in 6Li and 7Li. In addition the first superelastic electron spectrum is presented for experiments on lithium. A stepwise excitation technique is described with which cross sections for the electron impact excitation of the 3d9 4s2 2D state in copper can be measured. The experiments are complicated by the presence of D states in the incident copper beam. The origin of these D states is described as is a modification of the technique which leads to their removal.

scholarly journals Electron shelving of a superconducting artificial atom

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nathanaël Cottet ◽  
Haonan Xiong ◽  
Long B. Nguyen ◽  
Yen-Hsiang Lin ◽  
Vladimir E. Manucharyan
Keyword(s):  
Quantum Electrodynamics ◽  
Optical Pumping ◽  
Radiative Lifetime ◽  
Resonant Cavity ◽  
Coherence Time ◽  
Fluorescence Signal ◽  
Circuit Quantum Electrodynamics ◽  
Artificial Atom ◽  
Cavity Modes ◽  
Quantum Technology

AbstractInterfacing long-lived qubits with propagating photons is a fundamental challenge in quantum technology. Cavity and circuit quantum electrodynamics (cQED) architectures rely on an off-resonant cavity, which blocks the qubit emission and enables a quantum non-demolition (QND) dispersive readout. However, no such buffer mode is necessary for controlling a large class of three-level systems that combine a metastable qubit transition with a bright cycling transition, using the electron shelving effect. Here we demonstrate shelving of a circuit atom, fluxonium, placed inside a microwave waveguide. With no cavity modes in the setup, the qubit coherence time exceeds 50 μs, and the cycling transition’s radiative lifetime is under 100 ns. By detecting a homodyne fluorescence signal from the cycling transition, we implement a QND readout of the qubit and account for readout errors using a minimal optical pumping model. Our result establishes a resource-efficient (cavityless) alternative to cQED for controlling superconducting qubits.

scholarly journals Electron transfer by singlet excited state of porphyn and electron acceptor affinity in rigid medium: photoacoustic phase angle analysis

1997 ◽  
Vol 22 (0) ◽  
pp. 83-92
Author(s):  
Marinônio Lopes CORNÉLIO
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Phase Behavior ◽  
Electron Acceptor ◽  
Transfer Process ◽  
Spectral Region ◽  
Optical Excitation ◽  
Singlet Excited State ◽  
Electron Transfer Process ◽  
Excitation Process

Photoacoustic spectroscopy provides information about both amplitude and phase of the response of a system to an optical excitation process. This paper presents the studies of the phase in the electron transfer process between octaethylporphyn (OEP) and quinone molecules dispersed in a polymeric matrix. It was observed a tendency in the phase behavior to small values only in the spectral region near to 620 nm, while for shorter wavelength did not show any tendency. These measurements suggested that the electron transfer to acceptor occurred with the participation of octaethylporphyn singlet excited state.

scholarly journals Optische Anregung beim Ladungsaustausch von Ne+-Ionen mit den Molekülen N2, O2 und CO2 bei Energien unterhalb 250 eVolt

1968 ◽  
Vol 23 (9) ◽  
pp. 1386-1391
Author(s):  
H. Schlumbohm
Keyword(s):  
Charge Transfer ◽  
Cross Sections ◽  
Light Emission ◽  
Optical Excitation ◽  
Ground Level ◽  
Molecular Ions ◽  
Vibrational Bands ◽  
The Cross ◽  
Threshold Energies ◽  
Franck Condon

An experimental investigation of the light emission being excited by charge transfer collisions between ground level Ne+-ions and molecules of N2, O2, and CO2 at collisional energies up to 250 eVolts has shown optical excitation of the molecular ions being formed. The spectral scannings show the main system of N2+ and mainly the first negative system of O2+. Thus N2+ is formed in the excited B2Σu+-levels and O2+ in the b4Σg-- and to a smaller amount in the A2Πu-levels. Both reactions approach energy resonance within 1 to 3 eVolts as far as it is possible following the Franck-Condon principle. The spectral scanniings measured with CO2 as the target molecule indicate that at almost equal rates CO2+ is formed in the Ã2IIu-levels and by dissociative charge transfer CO+ in the upper A2II-levels of the observed comet-tail bands. The energy balance of this dissociative reaction is endothermic within 2,1 eVolts. — The cross sections for the excitation of definite vibrational bands of CO2+, CO+, and N2+ show threshold energies of several eVolts. After a primary increase the cross sections remain constant over the total energy range up to 250 eVolts. Only for the excitation of N2+ a broad maximum between 20 and 30 eVolts was found.

Correlation between Surface Charge Accumulation and Excitation Intensity Dependent Red-Shifted Micro-Photoluminescence of Si-Implanted Quartz with Embedded Si Nanocrystals

2004 ◽  
Vol 808 ◽  
Author(s):  
Chun-Jung Lin ◽  
Kuo-Cheng Yu ◽  
Hao-Chung Kuo ◽  
Miao-Jia Ou-yang ◽  
Gong-Ru Lin
Keyword(s):  
Electric Field ◽  
Stark Effect ◽  
Optical Excitation ◽  
Annealed Sample ◽  
Excitation Intensity ◽  
Red Shift ◽  
Surface Charges ◽  
Excitation Process ◽  
Si Nanocrystals ◽  
Surface Electric Field

ABSTRACTThe excitation intensity dependency of nanocrystallite Si (nc-Si) related micro-photoluminescence (μ-PL) from the multi-recipe Si-implanted quartz is characterized. The μ-PL at 724 nm contributed by nc-Si with 3-4 nm diameter is maximized after annealing at 1100°C for 3 hours. By increasing the excitation intensity from 10 kW/cm2 to 300 kW/cm2, the μ-PLs of 1-hr and 3-hr annealed quartz significantly red-shift from 723 nm to 725 nm and from 724 nm to 735 nm, respectively. This can be explained by the anomalous quantum stark effect due to a surface electric field oriented from photo-ionized nc-Si dots to quartz surface. After 1-hr illumination at power of 300 kW/cm2, the μ-PL peak wavelength of 3-hr annealed sample is further red-shifted by 2.5 nm. By measuring the accumulated surface charges built up during optical excitation process, the correlation between excitation-intensity dependent PL wavelength red-shift and the photo-ionized nc-Si surface electric-field related quantum stark effect is primarily elucidated.

scholarly journals Dynamics of frequency-swept nuclear spin optical pumping in powdered diamond at low magnetic fields

2019 ◽  
Vol 116 (7) ◽  
pp. 2512-2520 ◽  
Author(s):  
Pablo R. Zangara ◽  
Siddharth Dhomkar ◽  
Ashok Ajoy ◽  
Kristina Liu ◽  
Raffi Nazaryan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Optical Pumping ◽  
Spin Dynamics ◽  
Optical Excitation ◽  
Microwave Frequency ◽  
Sweep Rate ◽  
Nitrogen Vacancy ◽  
Diamond Surface

A broad effort is underway to improve the sensitivity of NMR through the use of dynamic nuclear polarization. Nitrogen vacancy (NV) centers in diamond offer an appealing platform because these paramagnetic defects can be optically polarized efficiently at room temperature. However, work thus far has been mainly limited to single crystals, because most polarization transfer protocols are sensitive to misalignment between the NV and magnetic field axes. Here we study the spin dynamics of NV−13C pairs in the simultaneous presence of optical excitation and microwave frequency sweeps at low magnetic fields. We show that a subtle interplay between illumination intensity, frequency sweep rate, and hyperfine coupling strength leads to efficient, sweep-direction-dependent 13C spin polarization over a broad range of orientations of the magnetic field. In particular, our results strongly suggest that finely tuned, moderately coupled nuclear spins are key to the hyperpolarization process, which makes this mechanism distinct from other known dynamic polarization channels. These findings pave the route to applications where powders are intrinsically advantageous, including the hyperpolarization of target fluids in contact with the diamond surface or the use of hyperpolarized particles as contrast agents for in vivo imaging.

scholarly journals Fine-structure energy levels and radiative rates in Al-like molybdenum

2017 ◽  
Vol 95 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Meifei Mao
Keyword(s):  
Configuration Interaction ◽  
Quantum Electrodynamics ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Ground Level ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
Relativistic Configuration Interaction ◽  
Configuration Interaction Calculations ◽  
Good Agreement

Based on relativistic wavefunctions from multiconfigurational Dirac–Hartree–Fock and configuration interaction calculations, energy levels, radiative rates, and wavelengths are evaluated for all levels of 3s23p, 3s3p2, 3s23d, 3p3, 3s3p3d, 3p23d, and 3s3d2 configurations of Al-like molybdenum ion (Mo XXX). Transition probabilities are reported for E1 and M2 transitions from the ground level. The valence–valence and core–valence correlation effects are accounted for in a systematic way. Breit interactions and quantum electrodynamics effects are estimated in subsequent relativistic configuration interaction calculations. Comparisons are made with the available data in the literature and good agreement has been found, which confirms the reliability of our results.

Superelastic electron scattering from calcium and lithium

1996 ◽  
Vol 74 (11-12) ◽  
pp. 984-990 ◽  
Author(s):  
P. J. O. Teubner ◽  
V. Karaganov ◽  
M. R. Law ◽  
P. M. Farrell
Keyword(s):  
Optical Pumping ◽  
Single Frequency ◽  
Optically Pumped ◽  
Close Coupling ◽  
Pumping System ◽  
State Orientation ◽  
Superelastic Scattering ◽  
Frequency Laser ◽  
Theory And Experiment ◽  
Good Agreement

Superelastic scattering experiment were performed on optically pumped calcium atoms at energies of 25.7 and 45 eV referred to the ground state. Orientation and alignment parameters derived from these experiments are compared with the predictions of several theories based on a distorted-wave formalism. The agreement between theory and experiment is unsatisfactory at the lower energy at all scattering angles. At the higher energy agreement improves at small scattering angles but is poor at middle angles. The results of our quantum electrodynamical calculation on optical pumping in lithium are compared with our observations. We find such good agreement between theory and experiment that we explore the possibility of superelastic scattering experiments on lithium atoms that are optically pumped with single-frequency laser light. A two-frequency pumping system is described and its use in the observation of superelastic scattering from lithium is discussed. Orientation and alignment parameters are presented at an equivalent energy of 21.8 eV for small angles. They are compared with those predicted by two close-coupling calculations. Excellent agreement is found between the present work and the convergent close-coupling theory of Bray.

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