The array biosensor: portable, automated systems.

With recent advances in surface chemistry, microfluidics, and data analysis, there are ever increasing reports of array-based methods for detecting and quantifying multiple targets. However, only a few systems have been described that require minimal preparation of complex samples and possess a means of quantitatively assessing matrix effects. The NRL Array Biosensor has been developed with the goal of rapid and sensitive detection of multiple targets from multiple samples analyzed simultaneously.

Experimental entanglement of four particles.

Quantum mechanics allows for many-particle wavefunctions that cannot be factorized into a product of single-particle wavefunctions, even when the constituent particles are entirely distinct. Such 'entangled' states explicitly demonstrate the non-local character of quantum theory, having potential applications in high-precision spectroscopy, quantum communication, cryptography and computation. In general, the more particles that can be entangled, the more clearly nonclassical effects are exhibited--and the more useful the states are for quantum applications.

Decoherence of quantum superpositions through coupling to engineered reservoirs.

The theory of quantum mechanics applies to closed systems. In such ideal situations, a single atom can, for example, exist simultaneously in a superposition of two different spatial locations. In contrast, real systems always interact with their environment, with the consequence that macroscopic quantum superpositions (as illustrated by the 'Schrodinger's cat' thought-experiment) are not observed.

Multiply loaded magneto-optical trap.

We report a two-chambered, differentially pumped system that permits rapid collection of trapped atoms with a vapor cell magneto-optical trap (MOT) and efficient transfer of these atoms to a second MOT in a lowerpressure chamber. During the transfer the atoms are guided down a long, thin tube by a magnetic potential, with 90(15%) transfer efficiency. By multiply loading, we accumulate and hold as many as 30 times the number collected by the vapor cell MOT.

External-cavity diode laser using a grazing-incidence diffraction grating.

An external cavity has been developed for use with commercial diode lasers. It uses a diffraction grating at grazing incidence for wavelength selection and output coupling. This configuration allows a GaAlAs diode laser to be tuned conveniently anywhere in a range greater than 20 nm.