Development of THz Superconducting Detectors at PMO S.C. Shi Purple Mt Observatory, CAS, China Key Lab of Radio Astronomy, CAS, China

Introduction THz Superconducting SIS & HEB Mixers THz Superconducting Imaging Array (TeSIA) TeSIA Developed with TES & MKIDs Conclusion Outline

Credit: S. Yamamoto Why Care About THz ? Structure formation in universe Evolution history of matter Fluctuation in early universe Galaxy formation Star formation Planet formation

1996－Cooled Schottky receiver 1998－1 st SIS receiver in China 2002－Upgraded SIS for multi-lines 2010－1 st Focal-plane receiver with 2SB SIS mixers with 2SB SIS mixers 0.1THz 1996－Room-temperature Schottky receiver 2005－1 st submm SIS receiver in China 2007－1 st NbN SIS mixer ever used in astronomy 0.5THz Development for 13.7m & POST 4

4K cryostat LO unit FFTS Digital bias Post IF unit Overall View of SSAR 波纹喇叭 LO 分配器 IF hybrid HEMT LNA HBT LNA Inside 4K Cryostat 2SB SIS Ji Yang, Wenlei Shan, Shengcai Shi, Qijun Yao, Yinxi Zuo, Shanhuai Chen, Aiqin Cao, Zhenhui Lin,“The Superconducting Spectroscopic Array Receiver (SSAR) for Millimeter-wave Radio Astronomy,” GSMM 2008, Nanjing, China, eds. Zhenghe Feng and Wei Hong, April 2008 (invited). 0.1THz Multibeam Receiver: SSAR 5

Imaging Observation with SSAR 40mins700mins 6

9.5K ~16K Appl Phys Lett (2008) 92: IEEE Trans Appl Supercond (2009)19: THz NbN SIS mixer firstly used for astronomy 0.5THz NbN Supercond. SIS Mixer 7

courtesy of ALMA Band 8Band 10 courtesy of SMA 2000－Development of submm SIS mixers, testing & observation on SMA 2003－Joint development of Band8 ( GHz) & Band10( GHz) SIS mixers Collaboration on SMA & ALMA 8 credit: NRAO NGC 6302 碳原子气 体精细分部

Dome A Basic facts about Dome A Altitude: 4093m (60km  10km) Lowest temp: -83℃ A plateau of small fluctuation 1300km from China’s Zhongshan station Extremely good THz/IR windows Where Is Dome A ?

preliminary design of DATE5 AntennaCassegrain Diameter 5m, with rms accuracy <10  m Receiver1x4 superconducting SIS & HEB mixer Band 350  m & 200  m IF BW4GHz x 4 beams x 2 bands FOV 5′×5′（200  m） Pointing≤2" Quasi Optics Antenna Subsystem Rx Subsystem Frontend Unit （H350 & H200） IF Unit (4GHzx8) LO Units （H350- & H200-ab) Remote Control Subsystem Antenna FFTS (4GHzx8) What Is DATE5 ?

All integrated in a 4K cryostat H350 band: 1x4 350  m H200 band: 1x4  m IF bandwidth: 4GHz x 8 Freq resolution: <100kHz inside view Quasi-Optics & Rx of DATE5

H200 HEB mixer TEM image of the HEB microbridge H200 HEB mixer chip 5.5 nm Si NbN SiOx NbN film thickness ~5.5nm Noise 1.26THz 500K 1.4THz Supercond HEB Mixer 1100K 1400K

Measured and simulated near-field and far-field beam 0.85THz Near-field measurement setup & diagram 1.4THz Supercond HEB Mixer

Combined THz QCL & HEB with a Gas Cell for the detection of 3.5THz methanol line 3.5THz 3rd DFB QCL (by MIT) THz HEB by SRON Measured 3.5THz methanol line Y. Ren, et al., App. Phys. Lett., 97, (2010) Y. Ren, et al., App. Phys. Lett, 98, (2011) Y. Ren, et al., Appl. Phys. Lett. 100, (2012) Y.Ren, et al., Appl. Phys. Lett., (2012) SRON/TUDelft PMO MIT … THz QCL Integrated with HEB

THz HEB by SRON DetectorTES or MKIDs Array size32x32 Band 350  m SensitivityBGLP, 1x W/Hz 0.5 TeSIA Quasi- optics TES/ MKIDs LT MUX RT MUX 0.3K/4K Cryocooler DAQ/ Control THz Supercond Imaging Array (TeSIA)

TES 8x8 PCB SQUIDASIC RT electronics 1/4K 4K 300K 0.3K ASIC SQUID TES Array 850um) with TDM TeSIA Developed with TES

Ti TES G=170~ 280 pW/K NEP dark ≈6.5e-17W/Hz 0.5 NbSi TES G=345 pW/K NEP dark ≈5.4e-17W/Hz 0.5 Ti & NbSi Superconducting TES

0.1~500MHz 4~8.5GHz MKIDs Array 850um) with FDM TeSIA Developed with MKIDs

Measured S21 vs T & P Typical Q~10 4 Measured 8x8 TiN MKIDs

QMC Dewar Windows M5 M4M3 Lens Array HDPE Lens 2HDPE Lens 1 Prototype To Be Tested on POST

0.5THz Receiver for China’s Space Station 0.5THz SIS with NbN twin junctions Nb vs NbN J. Li, Appl Phys Lett (2008) 92: J. Li, IEEE Trans Appl Supercond (2009)19: m Multi-Bands Telescope onboard China’s Space Station Nb vs NbN Less stringent requirement for cooling Easier suppression of Josephson effect Wider dc bias region of high stability Science cases for 0.5THz NbN SIS receiver CI line mapping to trace the molecular evolution of carbon across the universe Unbiased spectral line (e.g. H2O) survey toward star forming regions Distribution & dynamics of H 2 O in stratosphere Chemical process of the trace gases in stratosphere

Conclusion Atmospheric transmission from THz measured directly ever at Dome A, which is a rather promising site for THz astronomy, First generation instrument for DATE5 telescope will be two heterodyne receivers, and a 32x32 superconducting imaging array at 350  m (TeSIA) is under development, TeSIA is developed with TES and MKIDs, with TESs demonstrating a dark NEP better than and MKIDs a reasonably high quality factor, Prototype imaging array (850  m ) will be demonstrated on POST in 1~2 years.

Acknowledgment CAS & NSFC funding for Dome A Projects CCAA, Polar Institute (China) & PLATO Team (NSWU) for the deployment & operation of Dome A FTS Blue Sky (Canada) and QMC (UK) for good cooperation in developing Dome A FTS Team for CAS’s Int. Collaboration Partnership Program (PMO, CfA,...) APC/IAS/ASIAA for the fabrication of TES devices RIKEN for the fabrication of MKIDs devices MSPU/LERMA/SRON for the HEB collaboration