Compact Rydberg Atom-Based LF Transmitter

NASA is interested in electromagnetic sounding of ionospheric and magnetospheric plasma density structure at radio frequencies from kilohertz to MHz region. The majority of such soundings rely on passive sensing, i.e., they use either naturally occurring radiation or using transmitters of opportunity such as global navigation satellite system or ground-based transmitters used by worlds navies to transmit commands to submarines. Active sensing using the injection of ELF/VLF (300Hz -30kHz) frequency band electromagnetic waves into the Earths magnetosphere have played an important role in discovering and elucidating wave-particle interactions in near-Earth space. Efficient generation of low frequency waves, however, requires physically large antennas which essentially precludes their deployment in space. CRG is working to develop a completely novel type of transmitter for active sensing in the ionosphere and magnetosphere based on the induced transitions between highly excited Rydberg-atom energy levels. The advantage of such a transmitter is based on the fact that an atom makes an efficient electrically small radiator. Dr. Latypov of CRG first proposed it as a solution to the long-standing problem of submerged submarine communication with the air/space platforms (Latypov, 2022). Now, CRG considers its potential applications in space. The scope of this project is to evaluate the Rydberg atom-based technologies for potential NASA applications. The environment in space is significantly different from the environment on Earths surface and can vary depending on the location and other factors. Therefore, performance of the transmitter in space may significantly differ from its performance on the ground. CRG therefore will also review how the space conditions affect the performance of conventional antennas and investigate their possible impact on the Rydberg atom-based low frequency radiator. • This technology is important because low frequency (e.g., EF/VLF) transmitters tend to be either large or inefficient. The proposed technology provides a more compact and efficient transmitter of very low and extremely low frequency electromagnetic waves. • There are only a handful of EF/VLF installations around the world due to SWAP requirements and cost. • Rydberg atom-based transmitter overcomes the SWAP constraints imposed by the Chu-Harrington limit. • Proposed transmitter differs from piezoelectric antennas by the radiation mechanism (more efficient) • Dramatically reduced SWAP requirements make for possible active RF sensing at low frequencies from space • Compact VLF transmitters are also of practical importance for mining and geophysical surveying applications. • Additional potential applications may also include communication between Internet-of-Things (IoT) devices. Technical Objectives 1. To establish key requirements for LF transmitter 2. To predict the radiation spectrum and power level distribution of excited Rydberg atoms 3. To develop an experimental plan for characterization of the Rydberg atom-based radiator 4. To experimentally quantify the feasibility of a Rydberg atom-based radiator or determine how the Rydberg atom-based radiator may be affected by space plasma 5. To develop roadmap for further technology maturation and transition Work Plan Task 1: Establish requirements for Rydberg atom based LF transmitter Task 2: Perform modeling to predict radiation spectra and power distribution of excited Rydberg atoms Task 3: Perform SWAP-C analysis of hardware based on results of model prediction Task 4: Development of experimental test plan Task 5: Conduct experimental measurements to quantify spectra of excited Rydberg atoms OR investigate the effect of space plasma on Rydberg atom-based radiator Task 6: Summarize findings and prepare for next phase Proposed Deliverables 1. Kick-off meeting within 30 days of contract start 2. Quarterly progress reports 3. Interim technical review after 12 months 4. Final technical review 5. Final report
Benefits: Low frequency transmitter for space applications Geophysical surveying using low frequency electromagnetic waves Underwater surveying using low frequency electromagnetic waves • Submerged submarine communications • Near field LF communication for Internet of Things • VLF for space platforms to probe ionosphere and magnetosphere • VLF injection for controlled precipitation of radiation belt electrons • Beyond line of sight communication • Geophysical surveying using LF electromagnetic waves • Through-the-earth communication for mining applications