US Government As Represented by the Secretary of the Army

Jonathan C Schultz

Arthur H Carrieri

David J Owens

Jerold R Bottiger

Erik S Roese

Pascal I Lim

Kevin C Hung

Michael V Talbard

An optomechanical switching device, a control system, and a graphical user interface for a photopolarimetric lidar standoff detection that employs differential-absorption Mueller matrix spectroscopy. An output train of alternate continuous-wave COlaser beams [ . . . L:L. . . ] is directed onto a suspect chemical-biological (CB) aerosol plume or the land mass it contaminates (S) vis-&#xe0;-vis the OSD, with L[L] tuned on [detuned off] a resonant molecular absorption moiety of CB analyte. Both incident beams and their backscattered radiances from S are polarization-modulated synchronously so as to produce gated temporal voltage waveforms (scattergrams) recorded on a focus at the receiver end of a sensor (lidar) system. All 16 elements of the Mueller matrix (M) of S are measured via digital or analog filtration of constituent frequency components in these running scattergram data streams (phase-sensitive detection). A collective set of normalized elements {} (ratio to M) susceptible to analyte, probed on-then-off its molecular absorption band, form a unique detection domain that is scrutinized; i.e., any mapping onto this domain by incoming lidar data&#x2014;by means of a trained neural network pattern recognition system for instance&#x2014;cues a standoff detection event.

Photopolarimetric lidar dual-beam switching device and mueller matrix standoff detection system and method

An analog Mueller matrix data acquisition system (AMMS) acquiring middle-infrared Mueller (M) matrices of backscattering surfaces. The M-elements are measured by means of an active photopolarimetric sensor. The AMMS records nine M-elements simultaneously in groups of four modulo 2 incident continuous-wave COlaser beams&#x2014;one incident beam is tuned to a fundamental molecular absorption cross-section by the aerosol of detection interest (analytic wavelength &#x3bb;) while the other beam is detuned off that resonance band (reference wavelength &#x3bb;) and in the closest vicinity to &#x3bb;. Accordingly, those &#x394;M elements exhibiting susceptible behavior to the aerosol analyte, driven on-then-off its molecular vibrational resonance band, cues an identification event thus providing detection decision information. The AMMS is comprised of PEM reference frequency synthesizer, optical power regulation, data digitizer, and computer interface components in an interfaced and integrated framework that governs all operations of M-elements production by the photopolarimetric sensor.

Infrared Mueller matrix acquisition and preprocessing system and method

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Perryville, MD, United States of America

Jonathan C Schultz