Personnel: Researchers and Technologists: 18; Technicians: 8; Other technical and scientific personnel: 7; Graduate students and scholarships holders: 9; Administrative personnel: 0.5
The Division carries out research activities based mainly on classical and quantum optics to develop standards and measurement methods for time and frequency, photometry and radiometry, the purpose being to secure solid bases for metrology and the International System of Units through the foundations of quantum mechanics and the fundamental constants of physics. Measurement techniques cover a wavelength range spanning from ultraviolet to near infrared radiation.
The Division is responsible for the pertaining National standards as listed in DPR 591/1993, maintains and reproduces the SI units for the time, frequency, luminous intensity, illuminance, luminous flux, luminance, luminous exposure, and regular spectral transmittance quantities.
The research pursued in its laboratories concerns the atomic frequency standards and frequency synthesis, the generation of the Italian time scale, including time and frequency comparison and dissemination; the algorithm and mathematical methods for metrology and time scales, quantum optics, quantum information, innovative cryogenic photodetectors, photon quantities, lighting engineering and applications.
The national time scale UTC(IT) is generated directly by a hydrogen maser plus an AOG (Auxiliary Offset Generator), improving the short and medium term instability of the time scale, at the level of 4·10-13 (τ = 1 s) and 1·10-14 (τ = 1 d) respectively in terms of Allan deviation. The time offset of UTC(IT) versus UTC has been maintained within ± 30 ns for 97% of the time. The maximum frequency departure (over 5 days) of the time scale was 3·10-14 (3σ).
The Division is organized into four research programs, namely:
- Atomic frequency standards
- Time Scales and Algorithms
- Photometry and Radiometry
- Quantum optics
Full time equivalent (FTE) and % dedicated to various activities.
Products in the year 2008.
A primary frequency standard based on the cryogenic cesium fountain, working at liquid nitrogen temperature, was developed with a relative frequency accuracy of 1·10-16.
In particular, the first atomic clock signal was observed. As to the Ytterbium clock, MOT has been realised by blue radiation at 399 nm, as a first fundamental step towards the development of the frequency standard.
It is worth mentioning the invitation by ESA to take part in the experiments on the first Galileo satellites, the Galileo time scale generation and its synchronization through the Time Service Provider. Here the "GPS to Galileo Time Offset" has been estimated.
Transition-Edge Sensors were proven to be able to resolve the number of incoming photons when operating below 100 mK.
The density matrix of quantum optical states was successfully reconstructed by an on/off method. This result will impact significantly on the quantum optics community. Moreover, sub-shot noise spatial correlation was measured without subtraction of background, as a first step towards quantum imaging. The Alicki test on classicality of an optical state and Fedorov measurement of PDC entanglement were significant steps towards the identification of quantum properties of optical states.
The research activities carried out by the Division are well documented by 22 papers on Journals with an average IF of 3.09, 19 papers on Conference Proceedings, and 11 contract reports.
In 2008 the Division was involved in several new research cooperation projects. Of them 2 were Joint Research Projects (JRP) of the iMERA Plus program on Metrology sponsored by EURAMET, concerning the targeted Programme SI units and fundamental Constants. In detail, the Division participates in the JRP on New Optical Lattice clocks and coordinates the JRP Candela: towards photon quantum based standards".
The Division was also very active in the preparation of proposals for participation in research projects submitted to the EU. Other proposals, submitted upon calls by the Italian Ministry of Research and the Regione Piemonte, are under evaluation. New contracts with industry and private research laboratories were also proposed.
Important equipment improvements were made possible in 2008 by the external funding of an optical fibre link for telecommunications and a prototype for secure transmission of sensitive data. By successfully applying to INRIM calls, significant equipment was purchased for realising a correlated two-photon source by 4 wave mixing in cesium vapours.
The 2008 "European Frequency and Time" AWARD was given to Aldo Godone for his fundamental contributions to the development of chains of frequency synthesis and frequency standards in the far-infrared and to the field of atomic clocks based on optical pumping.
To comply with INRIM role as National Metrology Institute, the Division reproduces the units of measurement and maintains the related standards in the field of time and frequency, and radiometry and photometry. Measurement capabilities are developed to comply with the needs of the users. Within the participation in the Mutual Recognition Arrangement (MRA) of the CIPM, at the end of 2008 the Division had 39 calibration and measurement capabilities (CMC) internationally agreed and published in the BIPM Key Comparison Data Base.
The Division also participates in the MRA measurement comparison program: in 2008 measurements were carried out for the comparisons of luminous intensity.
International cooperation is of the utmost importance in metrological work. The Division participates in the activities of the Consultative Committee of Time and Frequency (CCTF) and the Consultative Committee of Photometry and Radiometry (CCPR), and of the EURAMET Technical Committees on Time and Frequency (TC-TF) and Photometry and Radiometry (TC-PR).
In 2008 the division delivered 251 calibration certificates, 37 test reports, and 22 other certificates delivered to industries, SIT centres and PMIs. Most of these certificates concern some of the 39 calibration and measurement capabilities (CMC) agreed within the MRA and published in the BIPM Key Comparison Data Base, which means that they are recognised world-wide. Tests are performed mainly on retroreflecting materials and signalling devices.
Supporting accreditation concerns 21 accredited laboratories. In 2008 INRIM participated in an international interlaboratory comparison on Luminance.
Support to industry is not limited to calibration but also involves several research contracts. Among others, it is worth mentioning tests concerning tunnel lighting.
Cooperation in research with foreign metrology Institutes, international and national universities and participation in scientific and standardisation organisations is also carefully pursued.