1 / 11

Dark Current Measurements of a Submillimeter Photon Detector

Dark Current Measurements of a Submillimeter Photon Detector. John Teufel Department of Physics Yale University. Yale: Minghao Shen Andrew Szymkowiak Konrad Lehnert Daniel Prober Rob Schoelkopf. NASA/GSFC Thomas Stevenson Carl Stahle Ed Wollack Harvey Moseley.

shania
Download Presentation

Dark Current Measurements of a Submillimeter Photon Detector

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dark Current Measurements of a Submillimeter Photon Detector John Teufel Department of Physics Yale University Yale: Minghao Shen Andrew Szymkowiak Konrad Lehnert Daniel Prober Rob Schoelkopf NASA/GSFC Thomas Stevenson Carl Stahle Ed Wollack Harvey Moseley Funding from NASA Explorer Tech., JPL, GSFC

  2. Overview The “SQPC” – a high-sensitivity sub-mm detector Contributions to dark currents Aluminum Junction Characterization Implications on overall sensitivity Future Work

  3. Sub-mm: ~ 100 mm -- 1 mm Sub-mm detectors today: Future NASA missions will require : Detectors should also be: Fast High quantum efficiency Scalable for arrays Motivation

  4. Antenna-coupled Superconducting Tunnel Junction (STJ) Photoconductor direct detector Each Photon with excites 2 quasiparticles Nb Al Al Au AlOx The SQPC: Single Quasiparticle Photon Counter Nb antenna Al absorber (Au) m ~ 1 STJ detector junction sub-mm photon Responsivity=2e/photon=e/D=5000A/W

  5. Rb V en SQPC Electrical Circuit Model and Noise Shot Noise Johnson Noise Amplifier Noise

  6. Temperature Thermal energy breaks Cooper pairs and excites quasiparticles BCS Predicts: Supercurrent Cooper pair tunneling affects the subgap current both at zero and finite voltages Due to rectification of the AC Jospephson Effect: Contributions to the Dark Current

  7. Bow Tie Antenna Detector 140 µm 1 µm Experimental Set-up and Testing • Small area junctions fabricated using double angle evaporation Device mounted in pumped He3 cryostat (T~250mK)

  8. X B Supercurrent Suppression SQUID w/ Rtot = 44 kW Al/AlOx/Al Junctions: ~ 60 x 100 nm

  9. Thermal Dark Current Measurements BCS Predicts: Tc =1.4 K I @ 50 mV Current [pA] Voltage [µV]

  10. Future Work: Detecting Photon Use a low thermal conductance blackbody to shine photons on detector

  11. Conclusions • SQPC: a sub-mm detector capable of NEP < • Characterized two sources dark current • Measured dark current < 0.5 pA • Tests with Blackbody source underway

More Related