Miniature Broadband Laser Magnetometer for ASW Arrays

This SBIR Phase II proposal describes development of a feasibility demonstration design and breadboard for the Miniature Broadband Laser Magnetometer (MBLM), an advanced high-sensitivity scalar laser magnetometer for next-generation undersea ASW Gradiometer Arrays. The MBLM offers the advanced capability of measuring scalar static and ELF magnetic fields with a sensitivity better than 1.0 pT/,cHz from 0.001 Hz to 50 Hz. The MBLM design is based on five innovations. The first is a hybrid sensor concept combining low-power nuclear free precession (NFP) for MHz signals with an optically-driven spin precession (OSP) locked-oscillator He4 mode for observation of ELF signals. The second innovation is development of long-relaxation time dual helium isotope cells combining isotopes 3 and 4 in a single cell in collaboration with the University of Texas¡VDallas. The third innovation is a fiber coupled laser pump source for pumping both isotopes. The fourth innovation is an omni-directional sense coil for the NFP mode. The fifth innovation is a low-power amplifier/processor chip for the NFP mode. The MBLM offers major advantages for ASW undersea arrays requiring detection and tracking in a gradiometer mode for reduction of geomagnetic noise in the detection band. A breadboard MBLM will be designed and demonstrated under this Phase II Project.