1. Atacama Large Millimeter/submillimeter Array Expanded Very Large Array Robert C. Byrd Green Bank Telescope Very Long Baseline Array NRAO Millimeter/THz Development Program: Current and Future

2. ALMA Development ALMA Development Workshop (March 21-22) Band 3 (or Band 2/3) MMIC LNA Upgrade Band 6 Balanced Mixer Upgrade SIS Mixer Development for Band 10 and beyond Focal Plane Arrays 2Millimeter/THz Development at the NRAO CDL

3. Band 3 (or 2/3) LNA Upgrade Using 35nm InP HEMT MMIC LNA 67-90 GHz 1 st iteration (EBLNA81) New designs funded by KISS (Keck Institute for Space Studies): EBLNA81B, EBLNAW+, EBLNAW0, MMLN100 – Fabrication complete, diced chips expected in ~2 weeks ~25% Sensitivity Improvement for Band 3 M. Morgan has designed a MMIC Schottky “SIS-substitute” mixer Directly applicable to GBT 3mm FPA Could also be used as W-band IF LNA for SIS or Schottky mixer 3Millimeter/THz Development at the NRAO CDL

4. EBLNA81B: Retuned for 67-90 GHz L13: 65 to 34um L14: 78 to 144um L14 L13 Millimeter/THz Development at the NRAO CDL

5. EBLNAW+: Cover full 68-116 GHz band 5 Millimeter/THz Development at the NRAO CDL

6. MMLN100: Cover full 68-116 GHz band 6 Millimeter/THz Development at the NRAO CDL

7. EBLNAW0: A “Tunable” MMIC LNA 7 Millimeter/THz Development at the NRAO CDL

8. UVML/NRAO/UAz SIS Collaboration 5 year program funded by ALMA Operations, beginning FY09 Advanced Materials and Processing Techniques – AlN Barriers for Wide Bandwidth (and NbTiN) – Nb/AlN/NbTiN SIS Junction Development (up to ~1.2 THz) Superconducting Hybrid Development (UAz funded) 0.7mm and 0.35mm Balanced/Sideband-Separating Mixers >1THz SIS Mixers (for SOFIA, ALMA Band 11, etc.) Balanced SIS Mixer for Band 6 (IF bandwidth to 4-12 GHz) 8Millimeter/THz Development at the NRAO CDL

9. SIS Materials and Processing Development Nb/AlN/NbTiN SIS mixers with AlN barriers are expected to yield near quantum-limited noise up to 1.2 THz Characterization of NbTiN film properties at 4K – Used cryogenic probe station to measure capacitance and penetration depth (surface inductance) – Will improve accuracy of mixer designs Delivery of hot deposition system in Jan. 2010 – Single crystal Nb tuning circuits – NbTiN with higher Tc – New materials… 9Millimeter/THz Development at the NRAO CDL

10. Silicon Membrane Beamlead Circuits Millimeter/THz Development at the NRAO CDL 10 3  m thick Silicon substrate Can be cut to arbitrary shape Can be patterned with Nb or NbTiN Beamleads allow for easy and repeatable assembly Used in current design of 700  m SIS mixer chips and superconducting 3dB hybrid chips

11. Drop-In Superconducting Hybrids For easy design and assembly of balanced and sideband-separating mixer modules 375-500 GHz (WR-2.1) prototype Works as expected at room temperature, currently being measured cold UVML funding partly from UAz 11Millimeter/THz Development at the NRAO CDL 287  m

12. Balanced SIS Mixers Rejection of LO noise 50-100 times less LO power 3dB greater dynamic range Currently processing 375-500 GHz prototype using Nb/AlN/Nb SIS mixer and superconducting hybrid 12Millimeter/THz Development at the NRAO CDL IF Output Superconducting 3dB RF Hybrid SIS Mixer Superconducting 180° IF Hybrid

13. Sideband-Separating SIS Mixers Reject atmospheric noise in other sideband Eliminate need for LO frequency switching to identify spectral lines Below is shown a balanced and sideband-separating SIS mixer 13Millimeter/THz Development at the NRAO CDL Absorbing Load Superconducting 3dB RF Hybrids SIS Mixer USB IF Output LSB IF Output SIS Mixer Superconducting 180° IF Hybrids

14. UVML/NRAO/UAz SIS Collaboration: Recent Highlights Factor of 10 improvement (from +/- 2 Ang. to +/- 0.2 Ang.) in repeatability of AlN thickness using new ICP growth protocol and rebuilt Succesful implementation of single-resist junction process, quicker and more repeatbale than pentablevel process Precise measurements of Nb and NbTiN films London penetration depth Room temperature verification 385-500 GHz superconducting hybrid on high-conductivity silicon membrane 14Millimeter/THz Development at the NRAO CDL

15. UVML/NRAO/UAz SIS Collaboration: Development Plan March 2011: Repeatable Jc on Nb/Al-AlN/Nb trilayer test circuits May 2011: 385-500 GHz SIS wafer complete June 2011: Single-ended and balanced 385-500 GHz SIS mixer measured Summer 2011: Nb/Al-AlN/NbTiN trilayer tests followed by band 10 SIS fabrication Fall 2011: Testing of sputtered Nb/AlN/NbTiN, NbTiN/AlN/NbTiN, hot- deposited NbTiN trilayers 15Millimeter/THz Development at the NRAO CDL