Denis V. Sutyrin

Test of Einstein Equivalence Principle for 0-spin and half-integer-spin atoms: Search for spin-gravity coupling effects

We report on a conceptually new test of the equivalence principle performed by measuring the acceleration in Earths gravity field of two isotopes of strontium atoms, namely, the bosonic (88)Sr isotope which has no spin versus the fermionic (87)Sr isotope which has a half-integer spin. The effect of gravity on the two atomic species has been probed by means of a precision differential measurement of the Bloch frequency for the two atomic matter waves in a vertical optical lattice. We obtain the values η=(0.2±1.6)×10(-7) for the Eötvös parameter and k=(0.5±1.1)×10(-7) for the coupling between nuclear spin and gravity. This is the first reported experimental test of the equivalence principle for bosonic and fermionic particles and opens a new way to the search for the predicted spin-gravity coupling effects.

Optical frequency transfer with a 1284 km coherent fiber link

We realized a coherent optical fiber link in Italy, with a fiber haul of 642 km. To characterize the link, we doubled the link to 1284 km, demonstrating a characterization technique based on the double round trip on a single fiber. The link is intended to significantly improve the frequency references used in radio-astronomy and precision measurements in atomic physics. The data analysis is based on the Allan deviation, whose expression is theoretically derived from the noise power spectrum. The demonstrated resolution is 3×10-19 in 1000 s and the uncertainty of the transfer is 5×10-19. The arming of a second fiber is avoided, and this could be rather beneficial to long hauls realizations for a continental fiber network for frequency and time metrology.

Development of a transportable laser cooled strontium source for future applications in space

We presented the first prototype of transportable laser-cooled strontium source. Novel design solutions have been discussed with a final volume, mass and power consumption budget for the atomic-package of 210 liters, 120 kg and 110 W, respectively. Most of the home made components have been assembled and tested. The system is currently under characterization and it is already able to produce a sample of about 108 atoms at 1 mK temperature. Next steps will be the integration of this system with a second stage cooling laser and with a transportable clock laser in order to realize a fully transportable optical lattice clock. Technical solutions, methods and know-how developed in this work will be used to built more robust, compact and advanced technology apparatus, with the nal aim to provide specifications for a future space optical lattice clock.

Absolute frequency measurement of unstable lasers with optical frequency combs

Here we report on absolute frequency measurements of a commercial high power CW diode-pumped solid-state laser (Coherent Verdi-V5). This kind of lasers usually presents large frequency jitter (up to 50 MHz) both in the short term (1 ms time scale) and in the long term (>10 s time scale). A precise measurement of absolute frequency deviations in both temporal scales should require a set of different devices (optical cavities, optical wave-meters), each suited for measurements only at a specific integration time. Here we demonstrate how a frequency comb can be used to overcome this difficulty, allowing in a single step a full characterization of both short (<1 ms) and long term (> 103 s) absolute frequency jitter with a resolution better than 1 MHz. We demonstrate in this way the flexibility of optical frequency combs for absolute frequency measurements not only of ultra-stable lasers but also of relatively unstable lasers. The absolute frequency calibration of the Verdi laser that we have obtained have been used in order to improve the accuracy of the measurements of the local gravitational acceleration value with 88Sr atoms trapped in 1D vertical lattices.

650-km Fiber Link in Italy for Optical Frequency Dissemination and Remote Clocks Comparison

We realized a 650-km optical fiber link in Italy for frequency dissemination and remote clocks comparison. We present its implementation and characterization at the 5×10-19 uncertainty level, discussing its future applications.

Carrier-envelope offset frequency noise analysis in Ti:sapphire frequency combs

Abstract. We experimentally study two Ti:sapphire optical frequency comb femtosecond regimes, respectively, with a linear and a nonlinear dependence of the carrier-envelope offset frequency (fCEO) on pump intensity. For both regimes, we study the effect of single- and multimode pump lasers on the fCEO phase noise. We demonstrate that the femtosecond regime is playing a more important role on the fCEO phase noise and stability than the pump laser type.