27 research outputs found
Cancellation of light-shifts in an N-resonance clock
We demonstrate that first-order light-shifts can be cancelled for an
all-optical, three-photon-absorption resonance ("N-resonance") on the D1
transition of Rb87. This light-shift cancellation enables improved frequency
stability for an N-resonance clock. For example, using a table-top apparatus
designed for N-resonance spectroscopy, we measured a short-term fractional
frequency stability (Allan deviation) 1.5e-11 tau^(-1/2) for observation times
1s< tau < 50s. Further improvements in frequency stability should be possible
with an apparatus designed as a dedicated N-resonance clock.Comment: 4 pages, 4 figure
Coherent-population-trapping resonances with linearly polarized light for all-optical miniature atomic clocks
We present a joint theoretical and experimental characterization of the coherent population trapping (CPT) resonance excited on the D(1) line of (87)Rb atoms by bichromatic linearly polarized laser light. We observe high-contrast transmission resonances (up to approximate to 25%), which makes this excitation scheme promising forminiature all-optical atomic clock applications. We also demonstrate cancellation of the first-order light shift by proper choice of the frequencies and relative intensities of the two laser-field components. Our theoretical predictions are in good agreement with the experimental results
A novel absorption resonance for all-optical atomic clocks
We report an experimental study of an all-optical three-photon-absorption
resonance (known as a "N-resonance") and discuss its potential application as
an alternative to atomic clocks based on coherent population trapping (CPT). We
present measurements of the N-resonance contrast, width and light-shift for the
D1 line of 87Rb with varying buffer gases, and find good agreement with an
analytical model of this novel resonance. The results suggest that N-resonances
are promising for atomic clock applications.Comment: 4 pages, 6 figure
Comparison of 87Rb N-resonances for D1 and D2 transitions
We report an experimental comparison of three-photon-absorption resonances
(known as "N-resonances") for the D_1 and D_2 optical transitions of thermal
87Rb vapor. We find that the D_2 N-resonance has better contrast, a broader
linewidth, and a more symmetric lineshape than the D_1 N-resonance. Taken
together, these factors imply superior performance for frequency standards
operating on alkali D_2 N-resonances, in contrast to coherent population
trapping (CPT) resonances for which the D_2 transition provides poorer
frequency standard performance than the D_1 transition.Comment: 3 pages, 4 figure
Coherent population trapping resonances with linearly polarized light for all-optical miniature atomic clocks
We present a joint theoretical and experimental characterization of the
coherent population trapping (CPT) resonance excited on the D1 line of 87Rb
atoms by bichromatic linearly polarized laser light. We observe high-contrast
transmission resonances (up to 25%), which makes this excitation scheme
promising for miniature all-optical atomic clock applications. We also
demonstrate cancellation of the first-order light shift by proper choice of the
frequencies and relative intensities of the two laser field components. Our
theoretical predictions are in good agreement with the experimental results.Comment: 8 pages, 7 figure
Realization of Coherent Optically Dense Media via Buffer-Gas Cooling
We demonstrate that buffer-gas cooling combined with laser ablation can be
used to create coherent optical media with high optical depth and low Doppler
broadening that offers metastable states with low collisional and motional
decoherence. Demonstration of this generic technique opens pathways to coherent
optics with a large variety of atoms and molecules. We use helium buffer gas to
cool 87Rb atoms to below 7 K and slow atom diffusion to the walls.
Electromagnetically induced transparency (EIT) in this medium allows for 50%
transmission in a medium with initial OD >70 and for slow pulse propagation
with large delay-bandwidth products. In the high-OD regime, we observe
high-contrast spectrum oscillations due to efficient four-wave mixing.Comment: 4 pages, 4 figures. V2: modified title, abstract, introduction,
conclusion; added references; improved theoretical fit in figure 3(b);
shortened slow light theory description; clarified simplicity of apparatus.
Final version as published in Phys. Rev.
Probing many-body dynamics on a 51-atom quantum simulator
Controllable, coherent many-body systems can provide insights into the
fundamental properties of quantum matter, enable the realization of new quantum
phases and could ultimately lead to computational systems that outperform
existing computers based on classical approaches. Here we demonstrate a method
for creating controlled many-body quantum matter that combines
deterministically prepared, reconfigurable arrays of individually trapped cold
atoms with strong, coherent interactions enabled by excitation to Rydberg
states. We realize a programmable Ising-type quantum spin model with tunable
interactions and system sizes of up to 51 qubits. Within this model, we observe
phase transitions into spatially ordered states that break various discrete
symmetries, verify the high-fidelity preparation of these states and
investigate the dynamics across the phase transition in large arrays of atoms.
In particular, we observe robust manybody dynamics corresponding to persistent
oscillations of the order after a rapid quantum quench that results from a
sudden transition across the phase boundary. Our method provides a way of
exploring many-body phenomena on a programmable quantum simulator and could
enable realizations of new quantum algorithms.Comment: 17 pages, 13 figure
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Far-Field Optical Imaging and Manipulation of Individual Spins with Nanoscale Resolution
A fundamental limit to existing optical techniques for measurementand manipulation of spin degrees of freedom is set by diffraction, which does not allow spins separated by less than about a quarter of a micrometre to be resolved using conventional far-field optics. Here, we report an efficient far-field optical technique that overcomes the limiting role of diffraction, allowing individual electronic spins to be detected, imaged and manipulated coherently with nanoscale resolution. The technique involves selective flipping of the orientation of individual spins, associated with nitrogen-vacancy centres in room-temperature diamond, using a focused beam of light with intensity vanishing at a controllable location, which enables simultaneous single-spin imaging and magnetometry at the nanoscale with considerably less power than conventional techniques. Furthermore, by inhibiting spin transitions away from the laser intensity null, selective coherent rotation of individual spins is realized. This technique can be extended to subnanometre dimensions, thus enabling applications in diverse areas ranging from quantum information science to bioimaging.Physic
Narrow-Linewidth Homogeneous Optical Emitters in Diamond Nanostructures via Silicon Ion Implantation
The negatively-charged silicon-vacancy (SiVâ) center in diamond is a bright source of indistinguishable single photons and a useful resource in quantum information protocols. Until now, SiVâ centers with narrow optical linewidths and small inhomogeneous distributions of SiVâ transition frequencies have only been reported in samples doped with silicon during diamond growth. We present a technique for producing implanted SiVâ centers with nearly lifetime-limited optical linewidths and a small inhomogeneous distribution. These properties persist after nanofabrication, paving the way for incorporation of high-quality SiVâ centers into nanophotonic devices.Physic
Ultra-Slow Light and Enhanced Nonlinear Optical Effects in a Coherently Driven Hot Atomic Gas
We report the observation of small group velocities of order 90 meters per
second, and large group delays of greater than 0.26 ms, in an optically dense
hot rubidium gas (~360 K). Media of this kind yield strong nonlinear
interactions between very weak optical fields, and very sharp spectral
features. The result is in agreement with previous studies on nonlinear
spectroscopy of dense coherent media