This Small Business Innovation Research (SBIR) Phase I project is focused on developing a new probe technology for high magnetic field sensing and measurement. The technology utilizes a circuit-free, atom-based field sensing element that affords absolute measurements of strong fields with high-speed all-optical readout that is free of electromagnetic interference, directly addressing capability gaps in existing technologies relevant to a variety of industries. A broad commercial potential is in fault-detection in condition-monitoring systems for motors and generators, where faults due to occurrences such as over-fluxing or magnetization can lead to major damage, costly repairs and production downtime. The atomic probe addresses an unmet need for reliable, localized measurements up to several Tesla of magnetic field within and surrounding conductive components in rotating machines for early fault detection. The technology also promises to expand capabilities of laboratory measurement instrumentation and contribute to experimental high magnetic field science requiring advanced instrumentation for measurement in the 1 to 100 Tesla range. The extraordinary opportunities for scientific research and technological development represented by investment in high magnetic field laboratories were set out in influential reports of the National Academies of Science (2004 and 2013). The field probe is expected to contribute to this on-going, multi-disciplinary effort. The intellectual merit of this project includes the research and demonstration of key components and capabilities of an atomic high magnetic field probe. The innovation lies in a fundamentally new measurement approach that provides robust, absolute-standard (atomic) measurement and sensing of magnetic fields up to tens of Tesla at high speed and precision with a compact, circuit-free, all-optical sensing element. The probe operates based on atomic physics principles that describe the spectroscopic response of atoms in strong magnetic fields, and quantum-optics phenomena that serve as a practical means to achieve all-optical readout of the atomic spectra, from which information on the magnetic field is obtained. During this project, theoretical atomic spectra in strong magnetic fields will be developed, tested and refined. A vapor-cell probe suitable for sensing strong magnetic fields will be designed, fabricated, and tested. Laboratory experiments will be performed to measure the atomic response to magnetic fields in the range of 1 Tesla at ppm sensitivity levels. The method will also be tested in time-varying and switching magnetic fields, on timescales of <100ms. Miniaturization of probes and read-out units will be initiated, leading towards robust and compact, practical sensing elements with higher operation speed and improved performance characteristics.