Quantum Optics at Otaniemi – MIKES-Aalto collaboration
Metrology is increasingly reliant on quantum phenomena. To meet the challenges, a new collaboration on applied quantum optics has been established between MIKES and Aalto University. The collaboration covers development of an optical ion clock, related spectroscopic techniques, and quantum-based photon standards. Together with the Micro and Quantum Systems Group of Aalto University, the newly established collaboration will pursue experiments on fundamental physics and investigate microfabrication techniques for quantum optics. In addition, the activities of the Metrology Research Institute have recently been integrated more closely with MIKES with a purpose of creating critical mass for ongoing and starting projects.
Micro and Quantum Systems Group
Ilkka Tittonen’s group, Micro and Quantum Systems (MQS) is part of the Department of Micro and Nanosciences at Aalto University (formerly Helsinki University of Technology). Located in Micronova, Centre for Micro and Nanotechnology, it has access to state-of-the-art cleanroom facilities. Research topics include development of nanofabrication techniques using such methods as atomic layer deposition (ALD), electron beam lithography (EBL), focused ion beam (FIB) processing and cryogenic deep reactive ion etching (DRIE), as well as nanoelectromechanical systems (NEMS) devices for high-precision sensing including photoacoustics and RF applications. Other activities are studies of thermoelectrics and chlorophyll-based optically active molecules. The group is also working with atom and quantum optics: laser cooling and trapping of rubidium and studying the influence of optical pumping on alkali atoms. Theoretical studies include semiconductor quantum structures and plasmonics in collaboration with Prof. Mackillo Kira and Prof. Stephan Koch in Marburg, Germany.
N. Chekurov, K. Grigoras, L. Sainiemi, A. Peltonen, I. Tittonen and S. Franssila. Dry fabrication of microdevices by the combination of focused ion beam and cryogenic deep reactive ion etching. J. Micromech. Microeng. 20, 085009 (2010).
N. Chekurov, K. Grigoras, A. Peltonen, S. Franssila and I. Tittonen. The fabrication of silicon nanostructures by local gallium implantation and cryogenic deep reactive ion etching. Nanotechnology 20, 065307 (2009).
T. Lindvall and I. Tittonen. Interaction-time-averaged optical pumping in alkali-metal-atom Doppler spectroscopy. Phys. Rev. A 80, 032505 (2009).
MIKES Time and Frequency Group
Mikko Merimaa’s group is responsible for time and frequency in Finland. The group operates caesium clocks and hydrogen masers to maintain the official time in Finland and contributes to the keeping of the international atomic time scale (TAI). In addition, this recently established group develops spectroscopic techniques and methods for industrial applications and conducts research on optical frequency standards.
To overcome the limitations of today’s best primary frequency standards several groups throughout the world are investigating clocks operating in the optical domain. This research work paves the way for the future redefinition of the second, to which MIKES contributes by investigating an optical clock based on a single Sr+ ion. The work at MIKES relies on previous research on optical frequency standards and precision spectroscopy. Experience with optical frequency comb technology provides means to relate optical frequencies to conventional atomic clocks. The MIKES optical clock project relies on active international collaboration, which takes place in the form of a bilateral researcher exchange with the National Research Council of Canada and a joint research project with the National Metrology Institutes of Germany, United Kingdom, France, and Italy within the framework of the EMRP.
P. Lemonde, U. Sterr, A. Curtis, L. Lorini, M. Merimaa. Optical clocks for a new definition of the second (OCS) A project of the European metrology research programme. Proceedings of the EFTF & IFCS, p. 320 (2009).
K. Kalliomäki, T. Mansten, M. Merimaa, and I. Iisakka. Maintenance of UTC(MIKE) in Finland by using a delay generator as a micro stepper. Proceedings of EFTF (2010).
Metrology Research Institute
Erkki Ikonen works as a professor at MIKES and at the Metrology Research Institute (MRI) of Aalto University. MRI operates under the Finnish name MIKES-Aalto Mittaustekniikka as the Finnish national standards laboratory for optical quantities. There have been significant recent advances in radiometry in the development of single-photon sources and single-photon detectors, associated with such technologies as quantum computing and quantum cryptography. The acceptance of these new quantum-based technologies requires improved traceability and reliability of measurements at the level of a few photons. Researchers from the MRI have contributed to the work at ETH Zurich, where two-photon interference has been demonstrated using two remote single molecules as bright solid-state sources of indistinguishable photons. Another international project improved reliability of few-photon measurements through a robust link to classical intensity measurements, where MIKES and MRI developed a new silicon based detector called PQED (Predictable Quantum Efficient Detector). The project achieved predictable quantum efficiency equal to unity within 80 ppm standard uncertainty at room temperature.
R. Lettow, Y. L. A. Rezus, A. Renn, G. Zumofen, E. Ikonen, S. Götzinger, and V. Sandoghdar. Quantum Interference of Tunably Indistinguishable Photons from Remote Organic Molecules. Phys. Rev. Lett. 104, 123605 (2010).
E. Ikonen. Coherence of Radiation as Studied by Multiple Coincidences of Photons and Particles. Optical Review 17, 239-247 (2010).
M. Sildoja, F. Manoocheri, and E. Ikonen. Reflectance Calculations for a Predictable Quantum Efficient Detector. Metrologia 46, S151-S154 (2009).
Text: Mikko Merimaa, Erkki Ikonen, Ilkka Tittonen