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A schematic cross-sectional view of NASAs Integrated-Photonic ESD. This image is from an issued patent for the invention (U.S. Patent No. 11,965,799).
Integrated-Photonic Electromagnetic Signal Detector
NASA’s ESD is a small form-factor electromagnetic signal detector fabricated on a photonic crystal substrate (e.g., silicon-on-insulator wafer, III-V platform). It integrates a (1) miniature on-chip antenna (e.g., microstrip antenna) aligned to the desired operational frequency, (2) 2-D photonic crystal, and (3) electro-optic polymer (located on the photonic crystal). At the heart of the detector is the 2D photonic crystal. Using an array of carefully sized pores or “nano-cavities,” a waveguide is formed that governs the crystal’s optical transmission properties. An electro-optic polymer (a material that shifts its refractive index in response to external electric fields) is used to coat the photonic crystal. The combination of the 2D photonic crystal and EO polymer make up the resonator. A compact antenna with separate active feed and ground regions is placed near the photonic crystal, creating a gap through which the electromagnetic signal couples to the photonic crystal structure. Under normal conditions (no external signal), the EO polymer’s refractive index remains unchanged, producing a stable resonant notch in the device’s optical transmission. When the antenna intercepts an electromagnetic wave, the resulting electric field modifies the EO polymer’s refractive index, causing a measurable shift in the resonator’s optical output. By monitoring this shift, a photodetector can accurately determine the presence and magnitude of the incoming electromagnetic wave. NASA’s low SWaP-C, high precision ESD can be adapted for use in a variety of systems including remote sensing instruments (e.g., radiometers, spectrometers), transceivers for 5G communications networks, and other electromagnetic signal detection applications. The invention is available for patent licensing.
Sensors
Legitimately accessed and used from Pexel under the Pexel license agreement, which allows for use of any photos on Pexel without attribution. Accessible here: https://www.pexels.com/photo/a-wind-farm-at-sunset-8420517/
Receiver for Long-distance, Low-backscatter LiDAR
The NASA receiver is specifically designed for use in coherent LiDAR systems that leverage high-energy (i.e., > 1mJ) fiber laser transmitters. Within the receiver, an outgoing laser pulse from the high-energy laser transmitter is precisely manipulated using robust dielectric and coated optics including mirrors, waveplates, a beamsplitter, and a beam expander. These components appropriately condition and direct the high-energy light out of the instrument to the atmosphere for measurement. Lower energy atmospheric backscatter that returns to the system is captured, manipulated, and directed using several of the previously noted high-energy compatible bulk optics. The beam splitter redirects the return signal to mirrors and a waveplate ahead of a mode-matching component that couples the signal to a fiber optic cable that is routed to a 50/50 coupler photodetector. The receiver’s hybrid optic design capitalizes on the advantages of both high-energy bulk optics and fiber optics, resulting in order-of-magnitude enhancement in performance, enhanced functionality, and increased flexibility that make it ideal for long-distance or low-backscatter LiDAR applications. The related patent is now available to license. Please note that NASA does not manufacturer products itself for commercial sale.
sensors
Split-Ring Torque Sensor, Top View
Split-Ring Torque Sensor
The SRTS enables measurement of position, velocity, and torque of a rotating system (e.g., actuator, motor, crankshaft, rotor, etc.) using two optical sensors and a single, custom-designed split-ring rather than the standard dual-ringed systems commonly used for similar applications. The split-ring is comprised of two structural arcs positioned in a concentric, coplanar relationship, wherein each arc is attached to a component capable of rotation (e.g., a lower leg and upper leg, where the SRTS acts as a knee). The two arcs contain indications or codes on their outer surfaces that are read by the optical sensors to determine the relative deflection of the structural arcs as they rotate. The SRTS configuration discussed above is limited to 180-degree applications. The addition of a third structural arc and a third optical reader, however, would enable 360-degree functionality. Tests have shown the SRTS has a high degree of tolerance to temperature differences and provides higher resolution measurements than competing technologies.
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