J Wen

Four-wave mixing with matter waves

The advent of the laser as an intense source of coherent light gave rise to nonlinear optics, which now plays an important role in many areas of science and technology. One of the first applications of nonlinear optics was the multi-wave mixing, of several optical fields in a nonlinear medium (one in which the refractive index depends on the intensity of the field) to produce coherent light of a new frequency. The recent experimental realization of the matter-wave ‘laser’,—based on the extraction of coherent atoms from a Bose–Einstein condensate—opens the way for analogous experiments with intense sources of matter waves: nonlinear atom optics. Here we report coherent four-wave mixing in which three sodium matter waves of differing momenta mix to produce, by means of nonlinear atom–atom interactions, a fourth wave with new momentum. We find a clear signature of a four-wave mixing process in the dependence of the generated matter wave on the densities of the input waves. Our results may ultimately facilitate the production and investigation of quantum correlations between matter waves.

Quantum key distribution with 1.25 Gbps clock synchronization

Clock recovery techniques at 1.25 Gbps enable continuous quantum key distribution at demonstrated sifted-key rates up to 1.0 Mbps. This rate is two orders of magnitude faster than has been reported previously

The National Institute of Standards and Technology glow discharge resonance ionization mass spectrometry system

A new resonance ionization mass spectrometry system at the National Institute of Standards and Technology using glow discharge atomization and continuous-wave lasers has been developed. Low concentrations of 133Cs in a silver matrix have been measured using this new system. In addition a detailed characterization of the glow discharge source and laser ionization processes are made.

New infrared beamline at the NIST SURF II storage ring

The success of the infrared program at the National Synchrotron Light Source has motivated the establishment of an infrared beamline at the Synchrotron Ultraviolet RAdiation Facility (SURF II) of the National Institute of Standards and Technology. Here, we describe the design of the infrared beamline and its associated infrared microscope instrumentation and show preliminary Fourier-transform infrared spectra. In addition, we present measurements of the long wavelength (> 1 cm) synchrotron emission and the noise spectrum of the infrared synchrotron radiation. The microwave measurements were undertaken to help assess the utility of SURF II as a submillimeter and far-infrared source.

High-speed quantum communication testbed

We describe the status of the NIST Quantum Communication Testbed (QCT) facility. QCT is a facility for exploring quantum communication in an environment similar to that projected for early commercial implementations: quantum cryptographic key exchange on a gigabit/second free-space optical (FSO) channel. Its purpose is to provide an open platform for testing and validating performance in the application, network, and physical layers of quantum communications systems. The channel uses modified commercial FSO equipment to link two buildings on the Gaithersburg, MD campus of the National Institute of Standards and Technology (NIST), separated by approximately 600 meters. At the time of writing, QCT is under construction; it will eventually be made available to the research community as a user facility. This paper presents the basic design considerations underlying QCT, and reports the status of the project.