Quantum measurement of a rapidly rotating spin qubit in diamond.

A controlled qubit in a rotating frame opens new opportunities to probe fundamental quantum physics, such as geometric phases in physically rotating frames, and can potentially enhance detection of magnetic fields. Realizing a single qubit that can be measured and controlled during physical rotation is experimentally challenging. We demonstrate quantum control of a single nitrogen-vacancy (NV) center within a diamond rotated at 200,000 rpm, a rotational period comparable to the NV spin coherence time .

Sub-kilohertz laser linewidth narrowing using polarization spectroscopy.

We identify several beneficial characteristics of polarization spectroscopy as an absolute atomic reference for frequency stabilization of lasers, and demonstrate sub-kilohertz laser spectral linewidth narrowing using polarization spectroscopy with high-bandwidth feedback. Polarization spectroscopy provides a highly dispersive velocity-selective absolute atomic reference based on frequency-dependent birefringence in an optically pumped atomic gas. The pumping process leads to dominance of the primary closed transition, suppressing closely-spaced subsidiary resonances which reduce the effective capture range for conventional atomic references.

Magneto-optical imaging of thin magnetic films using spins in diamond.

Imaging the fields of magnetic materials provides crucial insight into the physical and chemical processes surrounding magnetism, and has been a key ingredient in the spectacular development of magnetic data storage. Existing approaches using the magneto-optic Kerr effect, x-ray and electron microscopy have limitations that constrain further development, and there is increasing demand for imaging and characterisation of magnetic phenomena in real time with high spatial resolution. Here we show how the magneto-optical response of an array of negatively-charged nitrogen-vacancy spins in diamond can be used to image and map the sub-micron stray magnetic field patterns from thin ferromagnetic films.

In vivo imaging and tracking of individual nanodiamonds in drosophila melanogaster embryos.

In this work, we incorporate and image individual fluorescent nanodiamonds in the powerful genetic model system Drosophila melanogaster. Fluorescence correlation spectroscopy and wide-field imaging techniques are applied to individual fluorescent nanodiamonds in blastoderm cells during stage 5 of development, up to a depth of 40 µm. The majority of nanodiamonds in the blastoderm cells during cellularization exhibit free diffusion with an average diffusion coefficient of (6 ± 3) × 10(-3) µm(2)/s, (mean ± SD).

High-coherence electron and ion bunches from laser-cooled atoms.

Cold atom electron and ion sources produce electron bunches and ion beams by photoionization of laser-cooled atoms. They offer high coherence and the potential for high brightness, with applications including ultra-fast electron-diffractive imaging of dynamic processes at the nanoscale. The effective brightness of electron sources has been limited by nonlinear divergence caused by repulsive interactions between the electrons, known as the Coulomb explosion.

Detection of atomic spin labels in a lipid bilayer using a single-spin nanodiamond probe.

Magnetic field fluctuations arising from fundamental spins are ubiquitous in nanoscale biology, and are a rich source of information about the processes that generate them. However, the ability to detect the few spins involved without averaging over large ensembles has remained elusive. Here, we demonstrate the detection of gadolinium spin labels in an artificial cell membrane under ambient conditions using a single-spin nanodiamond sensor.

Compact diffraction grating laser wavemeter with sub-picometer accuracy and picowatt sensitivity using a webcam imaging sensor.

We describe a compact laser wavelength measuring instrument based on a small diffraction grating and a consumer-grade webcam. With just 1 pW of optical power, the instrument achieves absolute accuracy of 0.7 pm, sufficient to resolve individual hyperfine transitions of the rubidium absorption spectrum.

Spatial coherence of electron bunches extracted from an arbitrarily shaped cold atom electron source.

We describe the spatial coherence properties of a cold atom electron source in the framework of a quasihomogeneous wavefield. The model is used as the basis for direct measurements of the transverse spatial coherence length of electron bunches extracted from a cold atom electron source. The coherence length is determined from the measured visibility of a propagated electron distribution with a sinusoidal profile of variable spatial frequency.

Atom-scale ptychographic electron diffractive imaging of boron nitride cones.

Ptychographic coherent diffractive imaging (CDI) has been extensively applied using both x rays and electrons. The extension to atomic resolution has been elusive. This Letter demonstrates ptychographic electron diffractive imaging at atomic resolution, permitting identification of structure in a boron nitride helical cone at a resolution of order 1 Å, beyond that of comparative Z-contrast images.

Narrow linewidth tunable external cavity diode laser using wide bandwidth filter.

We demonstrate single mode operation of an external cavity diode laser (ECDL) employing an interference filter with multimode bandwidth for mode selection. A cateye reflector maximizes feedback efficiency and reduces susceptibility to intra-cavity optical misalignment. Narrow linewidths of 26 kHz are observed, and the laser can be tuned over 14 nm using a single 785 nm filter, without alteration of the output beam direction.

Heavy metal and pesticide content in commonly prescribed individual raw Chinese Herbal Medicines.

Heavy metal and pesticide contamination has previously been reported in Chinese Herbal Medicines (CHMs), in some cases at potentially toxic levels. This study was conducted to determine general patterns and toxicological significance of heavy metal and pesticide contamination in a broad sample of raw CHMs. Three-hundred-thirty-four samples representing 126 species of CHMs were collected throughout China and examined for arsenic, cadmium, chromium, lead, and mercury.

Mapping granular structure in the biological adhesive of Phragmatopoma californica using phase diverse coherent diffractive imaging.

This paper demonstrates the application of the high sensitivity, low radiation dose imaging method recently presented as phase diverse coherent diffraction imaging, to the study of biological and other weakly scattering samples. The method is applied, using X-ray illumination, to quantitative imaging of the granular precursors of underwater adhesive produced by the marine sandcastle worm, Phragmatopoma californica. We are able to observe the internal structure of the adhesive precursors in a number of states.

Dynamic sample imaging in coherent diffractive imaging.

As the resolution in coherent diffractive imaging improves, interexposure and intraexposure sample dynamics, such as motion, degrade the quality of the reconstructed image. Selecting data sets that include only exposures where tolerably little motion has occurred is an inefficient use of time and flux, especially when detector readout time is significant. We provide an experimental demonstration of an approach in which all images of a data set exhibiting sample motion are combined to improve the quality of a reconstruction.

Traditional Medicine Collection Tracking System (TM-CTS): a database for ethnobotanically driven drug-discovery programs.

Ethnopharmacological Relevance: Ethnobotanically driven drug-discovery programs include data related to many aspects of the preparation of botanical medicines, from initial plant collection to chemical extraction and fractionation. The Traditional Medicine Collection Tracking System (TM-CTS) was created to organize and store data of this type for an international collaborative project involving the systematic evaluation of commonly used Traditional Chinese Medicinal plants.

Materials And Methods: The system was developed using domain-driven design techniques, and is implemented using Java, Hibernate, PostgreSQL, Business Intelligence and Reporting Tools (BIRT), and Apache Tomcat.

Developing a library of authenticated Traditional Chinese Medicinal (TCM) plants for systematic biological evaluation--rationale, methods and preliminary results from a Sino-American collaboration.

While the popularity of and expenditures for herbal therapies (aka "ethnomedicines") have increased globally in recent years, their efficacy, safety, mechanisms of action, potential as novel therapeutic agents, cost-effectiveness, or lack thereof, remain poorly defined and controversial. Moreover, published clinical trials evaluating the efficacy of herbal therapies have rightfully been criticized, post hoc, for their lack of quality assurance and reproducibility of study materials, as well as a lack of demonstration of plausible mechanisms and dosing effects. In short, clinical botanical investigations have suffered from the lack of a cohesive research strategy which draws on the expertise of all relevant specialties.

Linewidths below 100 kHz with external cavity diode lasers.

The linewidth of external cavity diode lasers (ECDLs) is an increasingly important characteristic for experiments in coherent optical communications and atomic physics. The Schawlow-Townes and time-averaged linewidths depend on free parameters of the design, such as cavity length, power, and grating characteristics. We show that the linewidth is also sensitive to the focus, set by the distance between the laser and the collimating lens, due to the effect on the external cavity backcoupling efficiency.

Mode stability of external cavity diode lasers.

Mode stability is an important performance characteristic of external cavity diode lasers (ECDLs). It has been well established that the continuous mode-hop-free tuning range of a grating-feedback ECDL can be optimized by rotating the grating about a specific pivot location. We show that similar results can be obtained for other more convenient pivot locations by choosing instead the cavity length and grating location.

Off-resonant defocus-contrast imaging of cold atoms.

We demonstrate the retrieval of column-density images of cold atoms, using a noninterferometric phase-recovery technique based on a single off-resonant and defocused intensity image. The quantitative column density is retrieved via Fourier inversion and remains robust with respect to detuning and defocus. The technique offers excellent prospects for simple, nondestructive imaging of atoms in magnetic and optical traps and condensates.