The US Army Armament Research Development and Engineering Center (ARDEC) at Picatinny Arsenal has developed, tested, and patented an innovative laser microphone capable of measuring displacements of 40 picometers or less. ARDEC’s technology embeds a pulsed laser vibrometer platform that incorporates a photo-electromotive-force (photo-EMF) sensor and a pressure-sensing diaphragm in a laser microphone design. A key design feature is a multi-bounce architecture that enhances sensitivity by orders of magnitude. Using multiple bounces of the laser source against the diaphragm, signal strength is boosted without increasing noise levels. The dramatic improvement in signal-to-noise ratios enhances sensitivity and increases standoff detection distances. Time averaging is not required as the multiple bounces occur in a matter of nanoseconds.
In addition to exceptional sensitivity, the Army’s device offers excellent tolerance to optical speckles and can be used on moving objects, situations that plague competing platforms. Current development devices are small and rugged enough to be field portable. Tested devices have measured displacement values as low as 4 picometers. Femtometer displacement measurement is ultimately anticipated based on testing and design considerations.
- Highly Sensitive: Current prototype can consistently measure 40 picometer displacements; best displacement measurement achieved: 4 picometer
- Field Portable: Small, lightweight, and rugged
- Broad Applications: High sensitivity and stand-off detection capabilities enable a variety of manufacturing quality assurance, non-destructive testing, remote chemical detection, and medical applications
- US Ppatent 8,072,609 is available for license and commercialization
- Potential for collaboration with US Army Armament Research Development and Engineering Center