EUROMET PHORA TC Annual Report 18th EUROMET General Assembly

1. EUROMET PHORA TCAnnual Report18th EUROMET General Assembly Maria Luisa Rastello Bled, June 2004

4. EUROMET PHORA project #562 Collaboration in research Two photon metrology Coordinator: IEN partners : METAS, BNM-INM, NPL, IEN, NIST

5. Two photon metrology concerns the absolute measurement of photon quantities based on fundamental physical phenomena. Application fields of two photon technique: Metrology: Quantum Radiometry but also: Quantum Cryptography Chemistry, Biology and material science Optical fibre testing in communications and sensor applications Diode laser characterisation Laser ranging in space applications and telemetry

6. Parametric down-conversion (PDC) Spontaneous “decay” of a photon, inside a non-linear medium, into a pair of correlated photons • energy and momentum conservation: • simultaneous emission of the two photons Ref. D.N. Klyshko, Coherent photon decay in a non linear medium, Sov. Phys. JETP Lett.6,1967 S.E.Harris et al., Observation of tunable parmetric fluorescence, Phys.Rev.Lett. 18, 1967

7. Absolute calibration of photodetectors Ref. D.N. Klyshko, Sov. J. Quantum Electron. 10, 1112-1116,1988

8. Absolute calibration of photodetectors Feature: the deep interest in this technique is the definite possibility of establishing references at very low levels of intensity without turning to any other radiometric standard

9. Exchanging researchers and students 2000: NPL researcher at IEN for training; IEN researcher at NPL partecipating in the setting up of a new PDC facility for absolute detector calibration by correlated photons; NIST researcher at IEN working on single-photon detector bilateral comparison; 2001: BNM-INM researcher at IEN for training; 2002: IEN researcher at NIST for partecipating in the setting up of new experimental facility for absolute calibrations by correlated photons; 2003: BNM-INM researcher at IEN preparing a single-photon detector bilateral comparison.

10. The quantum efficiency of detector CP-00-A of BNM-INM has been measured by both IEN and BNM-INM at = 633 nm. BNM result is 0,7412  0,0083with a relative uncertainty of 1,1 %, while IEN result is 0,7412  0,0052with a relative uncertainty of 0,7 %.

11. BNM-INM measured the quantum efficiency by - the two-photon method and - by comparison with reference detectors directly linked to the cryogenic radiometer of BNM-INM. Quantum efficiency relative uncertaintyBNM-INM(1) 0,7412 ± 0,0083 1,1 %BNM-INM(2) 0,6943 ± 0,047 6,8 %

12. CCPR Working Group on Calibration and Measurement Capabilities (WG-CMC)NIST (Gaithersburg, USA), 10 May 2004F Hengstberger (CSIR-NML) Member(CCPR, SADCMET)C Matamoros (CENAM) Member (SIM)M Stock (BIPM) Member (secretary of the CCPR)J Gardner (CSIRO-NML) Member (APMP)M L Rastello (IEN) Member (EUROMET)

13. CCPR Working Group on Calibration and Measurement Capabilities (WG-CMC)TERMS OF REFERENCE- to coordinate and approve the definition of service categories requested by RMOs and to maintain lists of service categories, and - where necessary - rules for the preparation of CMC entries;- to agree on detailed technical review criteria;- to coordinate and, if necessary, conduct inter-regional reviews of CMCs submitted by RMOs for posting in Appendix C of the MRA;

14. CCPR Working Group on Calibration and Measurement Capabilities (WG-CMC)TERMS OF REFERENCE- to provide guidance on the range of CMCs supported by particular key and supplementary comparisons;- to suggest to the WG-KC areas where additional key and supplementary comparisons may be needed;- to coordinate the review of existing CMCs in the context of new results of key and supplementary comparisons.

15. MEMBERSHIP: Chairs of the Technical Committees of Regional Metrology Organizations (RMOs) dealing with photometry and radiometry. RMOs are entitled to include technical advisors in their delegation.Chairmanship rotates on an alphabetical basis between the RMOs. Terms of chairpersons will commence at the start of a WG-CMC meeting and end at the start of the next meeting. Present and incoming chairs will jointly prepare the draft agenda for the next meeting.

16. The formation of the WG-CMC complies with a request of the JCRB to all CIPM Consultative Committees to form such working groups.Its establishment is not meant not change the review process for CMCs in each RMO in any way.It is only after the inter‑regional review process has taken place in each reviewing RMO that a meeting of the RMO TC chairs by way of the WG‑CMC may be useful to resolve outstanding review issues. Where there are no issues to be resolved, the WG‑CMC will not even get involved.

18. Discussion on the way forward, timetableThe range of parameters submitted during rounds 1 and 2 now has been extended further to allow the submission of CMCs in most, if not all, of the outstanding service categories. An agreement has been reached on the list of these round-3 CMCs. The JCRB would then be informed of the arrangements and RMOs would be invited to submit round-three CMCs in these new service categories as soon as possible after the meeting.

19. Round 3 service categoriesComments on new list by RMOs to WG until the end of May 2004 CMC submissions acceptable from 1 June 2004. Executive Secretary of the CCPR: custodian of the list of service categories Latest approved version of this list available asap on the BIPM website.

20. Round 4 service categoriesApplications for new service categories submitted to the WG-CMC: after the completion of round 3 at any time on an “on demand” basis. New submissions of round 1 to 3 CMCs by RMOs acceptable at any time.

21. EUROMET PHORA TCAnnual report18th EUROMET General Assembly. Maria Luisa Rastello Bled, June 2004