Description: The overall objective of this Phase II R&D effort is to implement the optimized absolute frequency-stabilization methods tested and validated in Phase I to advance an integrated frequency-stabilization subsystem and upgrade a compact Rydberg laser package prototype for performance testing and demonstration at JPL NASA towards deployed QRR. The prototype will incorporate a ruggedized Rydberg laser that is wavelength tunable to access RF transitions at S-band and K-band with absolute frequency stability at the 100-kHz level (threshold) or 10kHz level (goal) for operation under typical vibration conditions in suborbital flight. In the Phase II effort, integrated optical atomic reference packages will be fabricated and integrated with the laser system, and stabilization electronics optimized to frequency-stabilization performance targets under target vibration conditions. Hardware upgrades of the frequency-stabilized Rydberg laser system will be implemented for automatic power optimization and leveling during wavelength tuning operations over nanometers to target RF resonances from S-band to K-band transition. The effort includes the development of actuated all-axis micro-optic couplers for on-board auto-alignment into diode and laser stages; a micro- laser with an upgraded wavelength tuner and opto-mechanical microcavity design will be evaluated and developed for robustness under DC-8 vibration environments and mitigate risk of optical beam alignment changes arising from general wear and tear in operation. A universal multi-color adaptor for plug-and-play use of sensors and probes with the prototype will be developed for demonstrations.

Benefits: The specific R&D conducted under the proposed Phase II work aim to advance JPL’s Quantum Rydberg Radar (QRR) effort. QRR based on Rydberg atom sensing is targeted to advance capabilities in remote sensing for Earth and space-based science missions in Surface Topography and Vegetation (STV) with a disruptive option for a small, low-cost architecture that can enable ultra-broad-band imaging to cover different observables and penetration depths that can be dynamically tuned to focus on certain bands of interest.

The proposed Phase II effort is aimed at creating a robust, frequency-stabilized Rydberg laser package for Rydberg atom quantum sensing. Rydberg atom sensing has potential application in RF markets including test and measurement, DoD, aerospace, and commercial communications, THz imaging, and semiconductor inspection.