We present and analyze a method of laser frequency stabilization via steady-state patterns of spectral holes in Eu3 :Y2SiO5. Three regions of spectral holes are created, spaced in frequency by the ground state hyperfine splittings of 151Eu3+ . The absorption pattern is shown not to degrade after days of laser frequency stabilization. An optical frequency comparison of a laser locked to such a steady-state spectral-hole pattern with an independent cavity-stabilized laser and a Yb optical lattice...

Topics: DTIC Archive, Cook,Shon, NATIONAL INST OF STANDARDS AND TECHNOLOGY BOULDER CO BOULDER United...

The goal of this project was to demonstrate the feasibility of realizing a large quantum computer by linking a series of elementary quantum computers (EQCs), using ensembles of atoms as qubits. We built all the tools for making an EQC.However, experimental work revealed that use of light shift imbalance only is not enough to achieve the required blockade. We have now shown why this is the case, and have identified how the blockade can be restored by using Rydberg interaction assisted...

Topics: DTIC Archive, Shahriar,Selim M, NORTHWESTERN UNIV CHICAGO IL CHICAGO United States, Quantum...

The approach of the instrument upgrade included improving the SHRU clocks by utilizing chip-scale atomic clocks (CSAC), enlarging battery packs to extend the operation duration, and adding data storage capacity for long-duration missions. The advantage of CSAC on clock precision can improve synthetic aperture processing and ocean acoustic tomography and achieve excellent long-term timing precision. A one-year deployment with continuous recording can be accomplished in the Arctic Ocean acoustics...

Topics: DTIC Archive, Tsong-Lin,Ying, Woods Hole Oceanographic Institution Woods Hole United States,...

The technical report focus on the program and on the major scientific achievements of the 6th Time Scale Algorithm Symposium and Tutorials. The development and testing of new tools adequate for the mathematical treatment of the time measurements is the core of the organized Symposium. The huge impact of the availability of the PFS (running continuously) is a key issue of time scale algorithms. The Kalman filter applied to the construction of national and international timescales has been...

Topics: DTIC Archive, Arias, F, Bureau International Poids et Mesures (BIPM) Sevres France, algorithms,...

An optical lattice clock probes a spectrally narrow electronic transition in an ensemble of optically trapped, laser-cooled atoms, for use as a time and frequency standard. To date, several lattice clocks have been demonstrated with superior stability and accuracy compared to primary frequency standards based on microwave transitions. Yet, the question of which atomic system (including the element and isotope) performs best as a lattice clock remains unsettled. This thesis describes the first...

Topics: DTIC Archive, Lemke,N D, Massachusetts Institute of Technology Cambridge United States, atomic...

We report a high accuracy measurement of the differential static polarizability for the clock transition in a Yb lattice clock, a key parameter for determining the blackbody(BBR) shift of this transition. We further report efforts to determine the [6s5dsup3Dsub1D6s6psup3Psub0] reduced dipole matrix element, a critical ingredient in the non-static correction to the BBR shift. In all, we have reduced the largest uncertainty in the Yb lattice clock (that stemming from the BBR shift) by an order of...

Topics: DTIC Archive, Sherman,J A, Massachusetts Institute of Technology Cambridge, United States,...

Narrow UV transitions in atomic Hg can be utilized for a high quality atomic frequency standard. The primary goal of the research supported by this grant was the development of a laser-cooled source of ultracold Hg atoms and the spectroscopic study of the doubly-forbidden clock transition to better understand its potential as a future atomic clock. During this funding period a novel UV laser system was developed to efficiently cool and trap atomic Hg to temperatures below 100 micro Kelvin. The...

Topics: DTIC Archive, Jones,R J, University of Arizona Tucson United States, optically pumped semiconductor...

Optical frequency combs serve as the clockwork of optical clocks, which are now the best time-keeping systems inexistence. The use of precise optical time and frequency technology in various applications beyond the research lab remains a significant challenge, but one that integrated microresonator technology is poised to address. Here, we report a silicon-chip-based microresonator comb optical clock that converts an optical frequency reference to a microwave signal.

Topics: DTIC Archive, Papp,Scott B, California Institute of Technology Pasadena United States, resonators,...

Contents: VLF; Omega Navigation system; A few comments on Omega; Precise time and time interval (PTTI) dissemination via the Loran-C system; Satellite communications system; Recent VHF/UHF satellite timing experiments at the National Bureau of Standards; 621B satellite system; Transit navigation satellite; Timation navigation satellite; Comments on NAVSAT time distribution; Moon-bounce time synchronization; Time dissemination methods for network and local television; Microwave, Optics, Lasers,...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *NAVIGATION SATELLITES, ATOMIC CLOCKS, FREQUENCY...

The Third Annual Department of Defense (DOD) Precise Time and Time Interval (PTTI) Strategic Planning Meeting, sponsored by the U.S. Naval Observatory was held November 16-18, 1971 in Washington, D.C., to accomplish the following objectives: exchange of practical information associated with PTTI, review present and future requirements for PTTI, review status of current and planned systems for PTTI dissemination, acquaint systems engineers and/or managers with precise time and frequency...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *GLOBAL COMMUNICATIONS, *NAVIGATION SATELLITES,...

Atomic Clocks provide \"stable\" signals that are mainly used to generate time scales and to measure differences of time between events. Each atomic clock can individually be characterized according to the stability of the scale it produces. Due to the stochastic behavior of each clock, usually clock ensembles are used to build more stable time scales. This process requires basically two steps. First it is required to individually characterize each time source to identify the...

Topics: Atomic clocks, Frequencies of oscillating systems, Measurement

;Contents: Resonator theory; Application of frequency control devices; Resonator research and development; Frequency and time dissemination; Frequency generation and measurement; Filters; Atomic and molecular frequency control.

Topics: DTIC Archive, ARMY ELECTRONICS COMMAND FORT MONMOUTH NJ, *FREQUENCY, SYMPOSIA, MOLECULAR BEAMS,...

Contents: Fundamental studies and quartz crystal; Filtering techniques and crystal filters; Crystal design and engineering; Crystal measurements; Oscillators and Synthesizers; Atomic and molecular frequency control; Timekeeping and distribution.

Topics: DTIC Archive, Gerber, E A, ARMY ELECTRONICS COMMAND FORT MONMOUTH NJ, *FREQUENCY, SYMPOSIA,...

Contents: Trends in frequency control applications; Fundamental crystal studies and crystal filters; Crystal measuring problems; Crystal design engineering and processing; Oscillators, synthesizers, and circuits; Timekeeping and distribution; Atomic and molecular frequency control; Optical frequency control.

Topics: DTIC Archive, Dressner, Jerry M, ARMY ELECTRONICS COMMAND FORT MONMOUTH NJ, *FREQUENCY, SYMPOSIA,...

Time between Near and Far changes by less than 1 ns for each 300s point in the PPP solution (1-sigma: 0.248 ns) A Cs atomic clock has 2-sigma instability around 100 ps at 300 s Two separate GPS traveling systems had calibrations only 450 ps apart Multi-day PPP solutions minimize day-boundary discontinuities Relative timing accuracy better than 1 ns* If the calibration works!

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *ATOMIC CLOCKS, *GLOBAL POSITIONING SYSTEM,...

Global Navigation Satellite System (GNSS) time and frequency transfer is among the most useful tools for comparisons of remote clocks. It represents the basis of the time laboratories contributions for the realization of Temps Atomique International (TAI). The GNSS reception chains (antenna, antenna cable, geodetic receiver), used currently to perform the time comparisons, must be calibrated periodically to ensure their accuracy and their long-term stability. The most widely approach used to...

Topics: DTIC Archive, CENTRE NATIONAL D'ETUDES SPATIALES TOULOUSE (FRANCE), *TIME, ATOMIC CLOCKS,...

In this paper, we present a frequency jump detector for space clocks based on two steps: a time-varying configurable deterministic trend, and a filter on the noises to improve the sensitivity. We prove and discuss the validity of the method by analyzing numerical simulations representing typical GNSS clocks.

Topics: DTIC Archive, POLITECNICO DI TORINO (ITALY), *ATOMIC CLOCKS, ALGORITHMS, NAVIGATION SATELLITES,...

In this paper, we present measurement results of the Digital Locked Loop system, developed by AGH University of Science and Technology, for microwave frequency distribution (here, 5 or 10 MHz) over optical fiber with precise stabilization of propagation delay in a relatively wide range of temperature variations. The main principle of the operation of the electronic delay lines is explained and the first measurement results obtained with the experimental setup using 20 km of optic fiber link are...

Topics: DTIC Archive, CENTRAL OFFICE OF MEASURES (GUM) WARSAW (POLAND), *DELAY LINES, *FREQUENCY STANDARDS,...

We describe the recent progress in our cesium atomic fountains at National Metrology Institute of Japan (NMIJ). We have developed three atomic fountains: NMIJ-F1, NMIJ-F2, and a truncated atomic beam fountain. NMIJ-F1 has been the primary frequency standard with uncertainty of 4 10(exp -15) since 2004. Especially in the last 4 years, we have reported the data to Bureau International des Poids et Mesures (BIPM) 21 times by operating NMIJ-F1 due to the progress in the stability and the...

Topics: DTIC Archive, NATIONAL METROLOGY INST OF JAPAN IBARAKI (JAPAN) FREQUENCY MEASUREMENT SYSTEMS...

Since 2004, the National Time Service Center of Chinese Academy of Sciences (NTSC) has been greatly improving in the number of atomic clocks, time comparison system, remote time transfer system, and so on. With the improvement of frequency control technology for the master atomic clock, the accuracy and stability of the Coordinated Universal Time UTC (NTSC) have also noticeably increased. From 2008 to 2009, the deviation between UTC (NTSC) and UTC has been less than 20 ns. The middle-term and...

Topics: DTIC Archive, CHINESE ACADEMY OF SCIENCES SHAANXI (CHINA) NATIONAL TIME SERVICE CENTER, *TIME...

The nucleus of the thorium-229 isotope possesses a first excited nuclear state (229mTh) at an exceptionally low energy of 7.8 + or - 0.5 eV above the nuclear ground state (229gTh), as determined by earlier indirect measurements. This is the only nuclear excited state known that is within the range of optical spectroscopy. This paper reports progress toward detecting the 229mTh state directly by luminescence spectroscopy in the vacuum ultraviolet spectral region. The estimated natural linewidth...

Topics: DTIC Archive, CALIFORNIA UNIV LOS ANGELES DEPT OF PHYSICS AND ASTRONOMY, *NUCLEAR ISOMERS,...

Here we report an imprecision below 10-14 with a simple, compact optical frequency standard based upon thermal calcium atoms. Using a Ramsey-Bord spectrometer we excite features with linewidths less than 5 kHz for the 1S0-3P1 intercombination line at 657 nm. We have measured a fractional frequency instability below 6 x 10-15 at 1 s, with good prospects for still quieter performance. The key remaining issue for this standard is how well first- and secondorder Doppler drifts can be suppressed....

Topics: DTIC Archive, MASSACHUSETTS INST OF TECH CAMBRIDGE, *ATOMIC CLOCKS, *CALCIUM, *FREQUENCY STANDARDS,...

The Stark shift of the ytterbium optical clock transition due to room temperature blackbody radiation is dominated by a static Stark effect, which was recently measured to high accuracy [J. A. Sherman et al., Phys. Rev. Lett. 108, 153002 (2012)]. However, room temperature operation of the clock at 10{-18} inaccuracy requires a dynamic correction to this static approximation. This dynamic correction largely depends on a single electric dipole matrix element for which theoretically and...

Topics: DTIC Archive, MASSACHUSETTS INST OF TECH CAMBRIDGE, *ATOMIC CLOCKS, *BLACKBODY RADIATION,...

Despite being a canonical example of quantum mechanical perturbation theory, as well as one of the earliest observed spectroscopic shifts, the Stark effect contributes the largest source of uncertainty in a modern optical atomic clock through blackbody radiation. By employing an ultracold, trapped atomic ensemble and high stability optical clock, we characterize the quadratic Stark effect with unprecedented precision. We report the ytterbium optical clock's sensitivity to electric fields (such...

Topics: DTIC Archive, MASSACHUSETTS INST OF TECH CAMBRIDGE, *ATOMIC CLOCKS, *OPTICAL PROPERTIES,...

In this work, we consider the light-shift coefficients observed in rubidium (Rb) atomic frequency standards, and how the units of measurement reported for light-shift coefficients trace back to the underlying physical parameters of the light-shift. We then measure the light-shift coefficient in an integrated filter-cell, commercial Rb clock, which is similar to the Rb clock design currently flying on Galileo and BeiDou satellites. We measure the light-shift coefficient for two different...

Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA PHYSICAL SCIENCES LABS, *ATOMIC CLOCKS, *FREQUENCY...

We demonstrated that an optical laser can operate with less than 1 photons on average inside the cavity while also obtaining significant spectral narrowing of the emitted light relative to the single atom transition linewidth. We further explored the power output properties and threshold conditions of this laser. We made direct measurements that showed that the lasing frequency can be made greater than 10000 times less sensitive to the resonance frequency of the optical cavity than is the case...

Topics: DTIC Archive, COLORADO UNIV AT BOULDER, *LASER BEAMS, ATOMIC CLOCKS, CAVITIES, MATHEMATICAL...

We have established the strontium molecular clock as the leading ultracold-molecule precision measurement platform. We can fully control the molecules internal and external quantum states, as in state-of-the-art atomic lattice clocks. Using the quantized molecular spectra in an optical lattice, we devised a new lattice thermometry method that is advantageous for many lattice experiments, including clocks and manybody physics studies. The full quantum control allowed us to observe deeply...

Topics: DTIC Archive, COLUMBIA UNIV NEW YORK, *ATOMIC CLOCKS, *MOLECULAR SPECTROSCOPY, *QUANTUM...

We present a method for accurate determination of atomic transition matrix elements at the 103 level. Measurements of the ac Stark (light) shift around magic-zero wavelengths, where the light shift vanishes, provide precise constraints on the matrix elements. We make the first measurement of the 5s-6p matrix elements in rubidium by measuring the light shift around the 421 and 423 nm zeros through diffraction of a condensate off a sequence of standing wave pulses. In conjunction with existing...

Topics: DTIC Archive, JOINT QUANTUM INST COLLEGE PARK MD, *DIFFRACTION ANALYSIS, *LIGHT,...

Atomic clocks have been instrumental in science and technology, leading to innovations such as global positioning, advanced communications, and tests of fundamental constant variation. Timekeeping precision at 1 part in 10 (exp 18) enables new timing applications in relativistic geodesy, enhanced Earth- and space-based navigation and telescopy, and new tests of physics beyond the standard model. Here, we describe the development and operation of two optical lattice clocks, both using...

Topics: DTIC Archive, MASSACHUSETTS INST OF TECH CAMBRIDGE, *ATOMIC CLOCKS, *INSTABILITY, ATOMIC ENERGY...

The goal of this research program is to investigate strongly-correlated many-body phases that emerge when interacting fermions occupy the p-orbital band of an optical lattice. Progress made toward this objective included demonstration of a site-resolved, continuously deformable two-dimensional honeycomb/triangular lattice and loading of Li-6 atoms into a triangular configuration of lattice beams. Further, a novel solid state laser source for 671 nm light was developed and new methods for...

Topics: DTIC Archive, PENNSYLVANIA STATE UNIV STATE COLLEGE, *FERMIONS, *LATTICE DYNAMICS, *OPTICAL...

We observed the Efimov effect the existence of a series of bound three body states related to one another by a universal geometric scaling factor in a three-component Fermi gas. Our work was the first to observe, in any physical system, an excited Efimov trimer state. In related work, we created a degenerate Fermi gas with SU(3) symmetry, a first step toward the quantum simulation of phenomena in QCD such as color superconductivity. Working with two-component Fermi gases, we demonstrated that...

Topics: DTIC Archive, PENNSYLVANIA STATE UNIV STATE COLLEGE, *COMPUTERIZED SIMULATION, *FERMIONS, *QUANTUM...

The state of the art is described in the determination and dissemination of time and the coordinate systems for satellite tracking. The report also recommends methods for improving the capabilities of the Space Track system.

Topics: DTIC Archive, MITRE CORP BEDFORD MA, *TIME, *TIME SIGNALS, ARTIFICIAL SATELLITES, ATOMIC CLOCKS,...

An ensemble of rubidium atomic fountain clocks has been put into operation at the US Naval Observatory (USNO). These fountains are used as continuous clocks in the manner of commercial caesium beams and hydrogen masers for the purpose of improved timing applications. Four fountains have been in operation for more than two years and are included in the ensemble used to generate the USNO master clock. Individual fountain performance is characterized by a white-frequency noise level below 2 10(exp...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *ATOMIC CLOCKS, PERFORMANCE(ENGINEERING), RUBIDIUM

We present a unifying theoretical framework that describes recently observed many-body effects during the interrogation of an optical lattice clock operated with thousands of fermionic alkaline earth atoms. The framework is based on a many-body master equation that accounts for the interplay between elastic and inelastic p-wave and s-wave interactions, finite temperature effects and excitation inhomogeneity during the quantum dynamics of the interrogated atoms. Solutions of the master equation...

Topics: DTIC Archive, CALIFORNIA INST OF TECH PASADENA INST FOR QUANTUM INFORMATION, *ATOMIC CLOCKS,...

Ramsey spectroscopy has become a powerful technique for probing nonequilibrium dynamics of internal (pseudospin) degrees of freedom of interacting systems. In many theoretical treatments, the key to understanding the dynamics has been to assume the external (motional) degrees of freedom are decoupled from the pseudospin degrees of freedom. Determining the validity of this approximation known as the spin model approximation has not been addressed in detail. Here we shed light in this direction...

Topics: DTIC Archive, CALIFORNIA INST OF TECH PASADENA, *SPECTROSCOPY, ATOMIC CLOCKS, DEGREES OF FREEDOM,...

We have performed an initial characterization of the stability of the U.S. Naval Observatory (USNO) cesium fountain atomic clock. This device has a short-term fractional frequency stability of up to 1.5 x 10(-13) tau (-1/2). This short-term performance enables us to measure hydrogen maser behavior over the short to medium term. We have recently implemented real time steering of a hydrogen maser with the fountain. Over a period of roughly 9 days of continuous operation, we have steered out the...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *ATOMIC CLOCKS, *CESIUM, CAVITIES, MASERS, STABILITY

In the rf-discharge lamp of an atomic clock, the inductor of a Colpitts or Hartley oscillator surrounds a glass bulb containing a vapor of Rb and a noble gas (typically Xe or Kr). Rf-energy is extracted from the field leading to ionization of the Rb, and in recombination with electrons these Rb ions produce the resonant light necessary for atomic signal generation. From an electrical perspective, the discharge can be viewed as a permeable medium located inside an inductor's coils. This...

Topics: DTIC Archive, AEROSPACE CORP EL SEGUNDO CA, *ATOMIC CLOCKS, *DISCHARGE LAMPS, *OSCILLATORS,...

The U.S. Naval Observatory (USNO) has provided timing for the Navy since 1830 and via DoD Directives 4650.05 and 4650.07 is the sole source of timing for the Department of Defense. In cooperation with other institutions, the USNO also provides timing for the United States and the international community. Its Master Clock (MC) is the source of UTC (USNO), USNO's realization of Coordinated Universal Time (UTC), which has stayed within 5 ns rms of UTC since 1999 and within 2 ns rms in 2012. The...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC TIME SERVICE DIV, *TIME STANDARDS, ATOMIC CLOCKS,...

The MINOS experiment uses a beam of predominantly muon-type neutrinos generated using protons from the Main Injector at Fermilab in Batavia, IL, and travelling 735 km through the Earth to a disused iron mine in Soudan, MN. The 10 microsecond-long beam pulse contains fine time structure which allows a precise measurement of the neutrino time of flight to be made. The time structure of the parent proton pulse is measured in the beamline after extraction from the Main Injector, and neutrino...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *NEUTRINOS, ATOMIC CLOCKS, DETECTORS, PARTICLE...

Tests of local position invariance (LPI) made by comparing the relative redshift of atomic clocks based on different atoms have been carried out for a variety of pairs of atomic species. In most cases, several absolute frequency measurements per year are used to look for an annual signal, resulting in tests that can span on order of a decade. By using the output of continuously running clocks, we carry out LPI tests with comparable or higher precision after less than 1.5 years. These include...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *ATOMIC CLOCKS, *INVARIANCE, *POSITION(LOCATION),...

Precision frequency metrology has valuable applications in cutting edge science, technology, and engineering. Current optical frequency standards utilize ultra cold ions or atoms, which requires complicated, nonportable infrastructure. The novel technique in our proposal allows us to access the narrow linewidth properties of an optical clock transition in a thermal mercury vapor cell. Using a thermal vapor cell removes all of the complicated infrastructure requirements and leaves us with a...

Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR, *ATOMIC CLOCKS, *METROLOGY, *OPTICAL PROPERTIES, CRYSTALS,...

Four rubidium fountains have been in operation for the past 1.2 years at USNO. Individual fountain performance applications to timekeeping and to tests of Local Position Invariance are presented.

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *ATOMIC CLOCKS, RUBIDIUM

The work supported by this AFOSR grant during the past year was focused on the fundamental physics and the applications of spin polarized species. The most notable accomplishments of the past year were: (1) basic work basic physics needed to transform gas-cell atomic clocks based on optically-pumped alkali-metal atoms from secondary frequency standards to primary frequency standards; (2) completion of studies of optical pumping and magnetic resonances of spin-polarized metastable Xe atoms as...

Topics: DTIC Archive, PRINCETON UNIV NJ DEPT OF PHYSICS, *ATOMIC PROPERTIES, *OPTICAL PUMPING, ATOMIC...

We report the observation of resolved atomic interaction sidebands (ISB) in the Sr87 optical clock transition when atoms at microkelvin temperatures are confined in a two-dimensional optical lattice. The ISB are a manifestation of the strong interactions that occur between atoms confined in a quasi-one-dimensional geometry and disappear when the confinement is relaxed along one dimension. The emergence of ISB is linked to the recently observed suppression of collisional frequency shifts. At the...

Topics: DTIC Archive, CALIFORNIA INST OF TECH PASADENA INST FOR QUANTUM INFORMATION, *ATOMIC CLOCKS,...

A variety of ways exist to combine clocks with different characteristics in a timescale. At the US Naval Observatory, for example, a process called dynamic weighting is used, which generates a timescale from a frequency scale that weighs recent maser data relatively higher than older maser data. A Kalman Filter could assign different phase, frequency, and frequency drift process noises to the different clock types. In this paper we use an ensemble of cesium and maser clocks to construct a...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *ATOMIC CLOCKS, CESIUM, KALMAN FILTERING, MASERS,...

Motivated by ongoing measurements at JILA, we calculate the recoil-free spectra of dipolar interacting fermions, for example ultracold heteronuclear molecules, in a one-dimensional lattice of two-dimensional layers or pancakes, spectroscopically probing transitions between different internal (e.g., rotational) states. We additionally incorporate p-wave interactions and losses, which are important for reactive molecules such as KRb. Moreover, we consider other sources of spectral broadening:...

Topics: DTIC Archive, COLORADO UNIV AT BOULDER, *FERMIONS, *MOLECULES, ATOMIC CLOCKS, DIPOLE MOMENTS,...

The U.S. Naval Observatory (USNO) maintains an ensemble of atomic clocks for the generation of a Master Clock, the physical realization of UTC(USNO). As many as 20 hydrogen masers and 70 commercial cesium clocks can contribute to the ensemble. The timescale used to generate UTC(USNO) relies on the short-term frequency stability of the masers and the long-term stability of the cesium clocks. To advance timekeeping activities, 7 rubidium fountain clocks are being added to the clock ensemble. The...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *ATOMIC CLOCKS, *FREQUENCY STANDARDS, *MEASUREMENT,...

We report observation of query pulse length dependent Ramsey interference (QPLD-RI), using pulsed Raman excitation in rubidium vapor. This is observed when a long, attenuated query pulse is used during pulsed Raman excitation. We explain the physical mechanism behind the QPLDRI using a Bloch vector model. We also use numerical solutions to time-dependent density matrix equations to simulate this interference effect showing qualitative agreement with experimental results. Presence of such...

Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC OPTICAL SCIENCES DIV, *ATOMIC CLOCKS, *ERROR...

This document is a compilation of technical papers presented at the 42nd Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting held 15-18 November in Reston, Virginia. Papers are in the following categories: - Recent developments in rubidium, cesium, and hydrogen-based atomic frequency standards, and in trapped-ion and space clock technology; - National and international applications of PTTI technology with emphasis on GPS and Galileo timing, atomic time scales, time...

Topics: DTIC Archive, NAVAL OBSERVATORY WASHINGTON DC, *TIME STANDARDS, *ATOMIC CLOCKS, SYMPOSIA, GLOBAL...

The NATO Research and Technology Organization (RTO) Research Task Group (RTG) on Urban, Indoor and Subterranean Navigation Sensors and Systems (SET-114, RTG-065) was formed to focus on how to enhance NATO military effectiveness through the improved use of advanced navigation sensor technologies. This report summarizes the work of the RTG, includes a description of the products generated by the group and provides a detailed technical overview of new and emerging navigation sensor and system...

Topics: DTIC Archive, NATO RESEARCH AND TECHNOLOGY ORGANIZATION NEUILLY-SUR-SEINE (FRANCE), *GUIDANCE,...