We demonstrate real-time stand-off detection and imaging of trace explosives using collinear, backscattered Coherent
Anti-Stokes Raman Spectroscopy (CARS). Using a hybrid time-resolved broad-band CARS we identify nanograms of
explosives on the millisecond time scale. The broad-band excitation in the near-mid-infrared region excites the
vibrational modes in the fingerprint region, and the time-delayed probe beam ensures the reduction of any non-resonant
contributions to the CARS signal. The strong coherent enhancement allows for recording Raman spectra in real-time.
We demonstrate stand-off detection by acquiring, analyzing, and identifying vibrational fingerprints in real-time with
very high sensitivity and selectivity. By extending the focused region from a 100-micron sized spot to a 5mm long line
we can obtain the spectral information from an extended region of the remote target with high spatial resolution. We
demonstrate fast hyperspectral imaging by one-dimensional scanning of the Line-CARS. The three-dimensional data
structure contains the vibrational spectra of the target at each sampled location, which allows for chemical mapping of
the remote target.
Multiple Input Multiple Output (MIMO) wireless communications vastly expand the capacity and connectivity of communications for forces operating in challenging environments such as urban or forested terrain. A MIMO architecture called BLAST (Bell Laboratories Layered Space-Time) has been formulated to realize these capacities. We have developed a packet version of BLAST, called PacketBLAST, specifically to support high mobility, ad-hoc, tactical communications on the move in challenging environments. PacketBLAST offers a number of benefits to tactical communications. We have implemented a first-ever, end-to-end mobile, ad-hoc network (MANET) of PacketBLAST nodes and have successfully tested it in a number of field demonstrations.
Experiments were conducted during four days in January and February 2001 at Tucson AZ, to measure the performance of an optical wireless link between two telescopes 8.7 km apart. The transmission rate was OC-3 (155 Mbps) and the maximum total radiated power was 29 dBm. Extreme fluctuations in the received 1550-nm beam were observed, and these occasionally caused error bursts. The error bursts had frequencies (a maximum of 12 per hour) and durations (mostly < 1 sec.) That were low enough to permit data transmission, e.g. via Ethernet TCP/IP. Fluctuations in the power of the 1550-nm received beam were positively correlated with variations in the elevation centroid. No correlations with meteorological measurements were found.
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