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Superconducting THz sources and receivers

Description:

OBJECTIVE: Develop manufacturable high-performance superconducting sources and receivers operating beyond 1 THz. Electronics operating in the millimeter wave band (THz) are important for several defense applications such as, imaging, detection, RADAR, spectroscopy, and wide bandwidth high-data-throughput communications. Development of THz components have proven difficult to develop especially at frequencies between 1 and 10 THz known as the “THz gap”. Power generation and receiver technologies are very inefficient and large scale production of high performance devices in this range is currently unfeasible. To control and manipulate radiation in this portion of the RF spectrum, especially at the higher end, new electronic devices must be developed. 

DESCRIPTION: Superconducting electronics based on Josephson junctions provide the most precise frequency control and detection accuracy over any other technology via the AC Josephson effect. Josephson junctions are precise to the quantum level and are used by NIST to define the volt. Unfortunately easy to process metallic superconductor Josephson junctions are limited to a maximum frequency of about 900 GHz. This is a fundamental limit determined by the superconducting energy gap. (The energy gap ofniobium is around 3mV). In contrast, ceramic high temperature superconductors (HTS) have energy gaps greater than 40 mV which may allow for frequencies above 10 THz [1]. This would provide a solution that can cover the entire THz gap! 

PHASE I: Task 1. From measurements of single direct write Josephson junction devices, use electrical data to design and simulate a planar voltage controlled oscillator HTS terahertz source based on arrays of Josephson junctions. Task 2. Design and simulate a THz receiver based on the AC Josephson effect. Task 3. Investigate low cost chip packaging solutions to integrate components into an imaging system. 

PHASE II: Task 1. Develop manufacturing process for Josephson array THz sources and detector chips. Task 2. Package oscillators and detectors for commercial electronic applications. Task 3. Construct and demonstrate a compact THz imaging system. 

PHASE III: Deliver components to industry for incorporation into commercial THz systems. 

REFERENCES: 

1: Welp et al. "Superconducting Emitters of THz radiation" Nature Photonics 7.9 (2013). 702-710.

2:  Ahn et al. "Terahertz Emission and Detection Both Based on highTcsuperconductors: Toward an Integrated Receiver", Appl. Phys. Lett. 102, 092601(2013)

3:  doi:10.1063/1.4794072

4:  Tsuimoto et al., "Terahertz imaging system using highTcsuperconductingoscillation devices", Appl. Phys. Lett. 102, 092601 (2013), doi: 10.1063/1.4794072

5:  Cybart et al. "Nano Josephson Superconducting Tunnel Junctions in YBa2Cu3O7-delta, Directly Patterned with a Focused Helium Ion Beam." Nature Nanotechnology 10.7 (2015): 598-602.

KEYWORDS: THz Sources, THz Radiation, Focused Helium Ion Beam, Josephson Junction Arrays, HTS Superconductors 

CONTACT(S): 

Harold Weinstock 

(703) 696-8572 

harold.weinstock@us.af.mil 

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