Report and Discussions Dong-Hoon Lee (KRISS) CCPR WG-SP meeting 8 July 2010, NPL

 to report the advances and demands in the field of few photon metrology ◦ annual activity report to WG-SP  to discuss upon the outstanding issues in the field of few photon metrology ◦ final report to CCPR WG-SP (after 3 years) recommending the concrete tasks of NMIs for this field

 Is the measurement of photons SI-traceable? ◦ What to do for traceable measurement?  Is the measurement accuracy of photons properly evaluated? ◦ What to do for accuracy improvement?  Can we measure everything what we need? ◦ What to do for better support to application fields?  Is the photon-based definition of “candela” possible? ◦ What to do for realization of a “photon-based scale”? ◦ What else?

 KRISS: Dong-Hoon Lee, Hee-Su Park, Sang-Kyung Choi  INRIM: Maria-Luisa Rastello, Ivo Degiovanni, Giorgio Brida  NRC: Joanne Zwinkels, Charles Bamber, Jeff Lundeen  PTB: Stefan Kueck, Gerhard Ulm  NIST: Sergey Polyakov, Alan Migdall, Sae-Woo Nam  NPL: Jessica Cheung  MIKES: Erkki Ikonen  NMIJ: Daiji Fukuda  Ad-hoc expert members from outside NMIs (invited)  Liaison members from CCEM (Jonathan Williams, NPL)

 Off-line meeting in conferences and workshops ◦ Single Photon Workshop (2009, 2011, 2013) ◦ NEWRAD (2008, 2011, 2014) ◦ Quantum Workshop in Torino (2008, 2010, 2012) ◦ And more to find in  On-line discussion ◦ Exchanging information through a WIKI forum (in preparation)  to combine with ◦ Questionnaires on the outstanding issues ◦ Preparation and review of the DG reports  Closing of DG in 2013 by submitting the final report ◦ Follow-up technical TGs for concrete tasks (comparisons, collaborations, etc.)

 Jan. 2010: Formation of a few photon metrology forum in Korea, supported by KRISS (KRISS, KAIST, POSTECH, PNU)  May 2010: Meeting in Quantum 2010 Workshop, Torino; topics arranged, members invited  A WIKI-site “Few Photon Metrology Forum” in preparation (open soon!)  Next meeting in NEWRAD (Sept. 2011)  Formation of a special session? (1 invited + 5 talks), but to combine with Q- candela project workshop (contact Maria-Luisa)

 Photon sources ◦ Heralded source based on twin photon generation ◦ Vacancies in diamonds, quantum dots  Photon detectors ◦ Geiger-mode counters (PMT, APD) ◦ Photon-number resolving devices (TES)  Characterization and quantification of photons ◦ Measurement of non-classical properties of light ◦ Calibration of spectral quantum efficiency  Application fields ◦ High-sensitivity imaging (remote sensing, satellite camera, medical imaging, etc.) ◦ Quantum information, quantum computing ◦ Quantum cryptography, quantum communication ◦ Photo-biology, photo-chemistry