"We propose a four-year program for the fabrication and characterization of high dynamic range, low background photon counting detectors that will support the next generation of UV/optical astronomy missions. These devices will serve as technology pathfinders for large format detectors ideal for space-flight applications. Advanced UV/optical detector systems are essential for addressing NASA's strategic science goals highlighted in the recent Decadal Survey, including a census of the atmospheric properties of extrasolar planets and constraining the physics of reionization in the distant universe. This program will address these goals through the development and testing of imaging High Event rate ReadOut Integrated Circuits (HEROICs), where independent pixel logic allows sustained count rates of order 1 kHz per pixel when coupled with a microchannel plate detector. In addition to directly addressing NASA's strategic science goals, this technology will extend the lifetime of UV detectors by operating at a lower gain and enabling a boot-strapping of primary standard stars to fainter magnitudes, both of which address calibration challenges for future high-sensitivity UV instruments. The proposed program will raise the technology readiness level of these devices from TRL 2 to TRL 4, while developing an architecture that will be compatible with flight applications in NASA's suborbital program. This technology would then be well-placed for use as a primary science detector on future UV/optical Explorer-class missions and ultimately large strategic missions such as ATLAST."