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At least 19 records

Nuclear Data Sheets for A = 71

The evaluated spectroscopic data are presented for experimentally known nuclides of mass 71 (Mn,Fe,Co,Ni,Cu,Zn,Ga,Ge,As,Se,Br,Kr). Excited-state data are nonexistent for {sup 71}Mn, {sup 71}Fe, {sup 71}Co and {sup 71}Kr. Significant new data have been added since the last evaluation of A=71 nuclides by M. Bhat (1993Bh02). Excited states are now known in {sup 71}Ni and {sup 71}Cu, and enhanced information about high-spin excitations is available for {sup 71}Ga, {sup 71}As and {sup 71}Br. The decay schemes of radioactive isotopes {sup 71}Mn and {sup 71}Fe are not known at all, and those for {sup 71}Co, {sup 71m}Ni and {sup 71}Kr are not known well. For the decay of {sup 71}Cu, {sup 71g}Ni, and {sup 71}Br, extensive data are available, but in the opinion of the evaluators the decay schemes still seem incomplete. This work supersedes earlier full evaluations of A=71 published by 1988Bh01, 1979Ke06 and 1973Al33, and the last one published in 'update' mode by 1993Bh02.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Slow polaritons with orbital angular momentum in atomic gases

Polariton formalism is applied for studying the propagation of a probe field of light in a cloud of cold atoms influenced by two control laser beams of larger intensity. The laser beams couple resonantly three hyperfine atomic ground states to a common excited state, thus forming a tripod configuration of the atomic energy levels involved. The first control beam can have an optical vortex, with the intensity of the beam going to zero at the vortex core. The second control beam without a vortex ensures the lossless (adiabatic) propagation of the probe beam at a vortex core of the first control laser. We investigate the storage of the probe pulse into atomic coherences by switching off the control beams and its subsequent retrieval by switching the control beams on. The optical vortex is transferred from the control to the probe fields during the storage or retrieval of the probe field. We analyze the conditions needed for the vortex to be transferred efficiently to the regenerated probe beam and discuss the possibilities of experimental implementation of the proposed scheme using atoms such as rubidium or sodium.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Ultralow-light-level all-optical transistor in rubidium vapor

An all-optical transistor (AOT) is a device in which one light beam can efficiently manipulate another. It is the foundational component of an all-optical communication network. An AOT that can operate at ultralow light levels is especially attractive for its potential application in the quantum information field. Here, we demonstrate an AOT driven by a weak light beam with an energy density of 2.5 × 10{sup −5} photons/(λ{sup 2}/2π) (corresponding to 6 yJ/(λ{sup 2}/2π) and about 800 total photons) using the double-Λ four-wave mixing process in hot rubidium vapor. This makes it a promising candidate for ultralow-light-level optical communication and quantum information science.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Emergence of currents as a transient quantum effect in nonequilibrium systems

Most current calculations are based on equilibrium or semi-equilibrium models. However, except for very special scenarios (like ring configuration), the current cannot exist in equilibrium. Moreover, unlike with equilibrium scenarios, there is no generic approach to confront out-of-equilibrium currents. In this paper we used recent studies on transient quantum mechanics to solve the current, which appears in the presence of very high density gradients and fast transients. It shows that the emerging current appears instantaneously, and although the density beyond the discontinuity is initially negligible the currents there have a finite value, and remain constant for a finite period. It is shown that this nonequilibrium effect can be measured in real experiments (such as cooled rubidium atoms), where the discontinuity is replaced with a finite width (hundreds of nanometers) gradient.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Effects of water concentration in the coating solution on the wall relaxation rate of octadecyltrichlorosilane coated rubidium vapor cells

High quality anti-relaxation surface coatings for atomic vapor cells are essential for the preservation of atomic spin coherence and the enhancement of measurement sensitivity. In this paper, we studied the effects of water concentration in octadecyltrichlorosilane (OTS) coating solution on the relaxation rate and its reproducibility of OTS coated Rubidium vapor cells. We found that appropriate water concentration can improve the anti-relaxation performance of OTS coated cells.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Intracavity sum-frequency generation of a 795 nm pulsed laser with a short pulse width based on two MgO : PPLN crystals

We report a 795 nm tunable pulsed laser with intracavity sum-frequency generation (SFG) based on an optical parametric oscillator (OPO) pumped by a 1064 nm laser. The cavity consists of two periodically poled MgO : PPLN crystals, the periods of which are 22.0 and 31.0 μm. The crystal with the period of 31.0 μm is used to generate a mid-IR beam, while the other crystal is used for SFG of the pump beam and the mid-IR beam. The pulsed width of the 795 nm laser is 3.6 ns, and the repetition rate of the laser is 35.3 kHz. The peak power of the laser is 2.8 kW with a linewidth of 0.35 nm. The 795 nm laser threshold pump power is 1.4 W and the optical-to-optical efficiency of 1064 nm to 795 nm is 5.7% at a maximum output power. The laser is supposed to be a kind of a competitive near-IR laser source for studying a diode-pumped rubidium laser. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Ultrafast laser control of backward superfluorescence towards standoff sensing

We study infrared backward cooperative emission in a rubidium vapor induced by ultrafast two-photon optical excitations. The laser coherent control of the backward emission is demonstrated by using a pair of 100 fs pulses with a variable time delay. The temporal variation (quantum beat) of the backward beam intensity due to interference of atomic transitions in the rubidium atomic level system 5S-5P-5D is produced and controlled. Based on the obtained experimental results, we discuss possible applications of the developed approach for creation of an effective “guide star” in the sodium atomic layer in the upper atmosphere (mesosphere)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Atomic vapor spectroscopy in integrated photonic structures

We investigate an integrated optical chip immersed in atomic vapor providing several waveguide geometries for spectroscopy applications. The narrow-band transmission through a silicon nitride waveguide and interferometer is altered when the guided light is coupled to a vapor of rubidium atoms via the evanescent tail of the waveguide mode. We use grating couplers to couple between the waveguide mode and the radiating wave, which allow for addressing arbitrary coupling positions on the chip surface. The evanescent atom-light interaction can be numerically simulated and shows excellent agreement with our experimental data. This work demonstrates a next step towards miniaturization and integration of alkali atom spectroscopy and provides a platform for further fundamental studies of complex waveguide structures.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

A stable frequency comb directly referenced to rubidium electromagnetically induced transparency and two-photon transitions

We demonstrate an approach to create a stable erbium-fiber-based frequency comb at communication band by directly locking the combs to two rubidium atomic transitions resonances (electromagnetically induced transparency absorption and two-photon absorption), respectively. This approach directly transfers the precision and stability of the atomic transitions to the comb. With its distinguishing feature of compactness by removing the conventional octave-spanning spectrum and f-to-2f beating facilities and the ability to directly control the comb's frequency at the atomic transition frequency, this stable optical comb can be widely used in optical communication, frequency standard, and optical spectroscopy and microscopy.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Photonic-band-gap properties for two-component slow light

We consider two-component ''spinor'' slow light in an ensemble of atoms coherently driven by two pairs of counterpropagating control laser fields in a double tripod-type linkage scheme. We derive an equation of motion for the spinor slow light (SSL) representing an effective Dirac equation for a massive particle with the mass determined by the two-photon detuning. By changing the detuning the atomic medium acts as a photonic crystal with a controllable band gap. If the frequency of the incident probe light lies within the band gap, the light experiences reflection from the sample and can tunnel through it. For frequencies outside the band gap, the transmission and reflection probabilities oscillate with the increasing length of the sample. In both cases the reflection takes place into the complementary mode of the probe field. We investigate the influence of the finite excited state lifetime on the transmission and reflection coefficients of the probe light. We discuss possible experimental implementations of the SSL using alkali-metal atoms such as rubidium or sodium.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Realization of low frequency and controllable-bandwidth squeezing based on a four-wave-mixing amplifer in rubidium vapor

We experimentally demonstrate the creation of two correlated beams generated by a nondegenerate four-wave-mixing amplifier at {lambda} = 795 nm in hot rubidium vapor. We achieve intensity difference squeezing at frequencies as low as 1.5 kHz which is so far the lowest frequency to observe squeezing in an atomic system. The squeezing spans from 5.5 to 16.5 MHz with a maximum squeezing of {approx}5 dB at 1 MHz. We can control the squeezing bandwidth by changing the pump power. Both low frequency and controllable bandwidth squeezing show great potential in sensitivity detection and precise control of the atom optics measurement.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking

We demonstrate an easily tunable locking scheme for stabilizing frequency-sum of two lasers on a two-photon ladder transition based on polarization rotation in warm rubidium vapors induced by magnetic field and circularly polarized drive field. Unprecedented tunability of the two-photon offset frequency is due to strong splitting and shifting of magnetic states in external field. In our experimental setup, we achieve two-photon detuning of up to 700 MHz.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Perforated hollow-core optical waveguides for on-chip atomic spectroscopy and gas sensing

A hollow-core waveguide structure for on-chip atomic spectroscopy is presented. The devices are based on Anti-Resonant Reflecting Optical Waveguides and may be used for a wide variety of applications which rely on the interaction of light with gases and vapors. The designs presented here feature short delivery paths of the atomic vapor into the hollow waveguide. They also have excellent environmental stability by incorporating buried solid-core waveguides to deliver light to the hollow cores. Completed chips were packaged with an Rb source and the F = 3 ≥ F′ = 2, 3, 4 transitions of the D2 line in {sup 85}Rb were monitored for optical absorption. Maximum absorption peak depths of 9% were measured.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Experimental generation of tripartite polarization entangled states of bright optical beams

The multipartite polarization entangled states of bright optical beams directly associating with the spin states of atomic ensembles are one of the essential resources in the future quantum information networks, which can be conveniently utilized to transfer and convert quantum states across a network composed of many atomic nodes. In this letter, we present the experimental demonstration of tripartite polarization entanglement described by Stokes operators of optical field. The tripartite entangled states of light at the frequency resonant with D1 line of Rubidium atoms are transformed into the continuous variable polarization entanglement among three bright optical beams via an optical beam splitter network. The obtained entanglement is confirmed by the extended criterion for polarization entanglement of multipartite quantized optical modes.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Ultra-sensitive high-density Rb-87 radio-frequency magnetometer

Radio-frequency (RF) atomic magnetometers (AMs) can be used in many applications, such as magnetic resonance imaging and nuclear quadrupole resonance. High-density AMs provide both superior sensitivity and large bandwidth. Previously, high-density potassium AMs were demonstrated, but these magnetometers have various disadvantages, such as high-temperature of operation and bulky design. We demonstrate a rubidium-87 RF AM with 5 fT/Hz{sup 1/2} sensitivity (3 fT Hz{sup 1/2} probe noise), which is comparable to that of the best potassium magnetometers. Our magnetometer also features a simple fiber-optic design, providing maximum flexibility for magnetic-field measurements.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Quantum control in two-dimensional Fourier-transform spectroscopy

We present a method that harnesses coherent control capability to two-dimensional Fourier-transform optical spectroscopy. For this, three ultrashort laser pulses are individually shaped to prepare and control the quantum interference involved in two-photon interexcited-state transitions of a V-type quantum system. In experiments performed with atomic rubidium, quantum control for the enhancement and reduction of the 5P{sub 1/2}{yields} 5P{sub 3/2} transition was successfully tested in which the engineered transitions were distinguishably extracted in the presence of dominant one-photon transitions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Creation of the first Russian time and frequency standard on a fountain of ultracold rubidium atoms

Technical specific features of the first Russian rubidium frequency standard of a fountain type are described, which are distinct from those of abroad analogues. Test results of separate systems and the metrological characteristics of the standard are presented. The achievable output frequency instability is 4 × 10{sup −16} per measurement interval of 24 hours and 1 × 10{sup −16} per 16 days. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Transient processes under dynamic excitation of a coherent population trapping resonance

It is shown for the first time that under dynamic excitation of a coherent population trapping resonance in Rb vapours at different bichromatic pump modulation frequencies from a few tens of hertz and higher, the resonance is dramatically deformed as a result of emerging intensity oscillations of radiation transmitted through an Rb vapour cell. A significant change in the shape of the resonance under its dynamic excitation is confirmed experimentally and theoretically. A possible impact of the identified changes in the shape of the coherent population trapping resonance on the stability of an atomic clock is qualitatively discussed. (optical traps)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗