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Advances in ultra-stable lasers now permit sub-Hz resolution of optical atomic transitions. At this level, weak interactions by any ordinary scale can in fact dominate the dynamics of the interrogated atoms, even for spin polarized fermions at ultralow temperatures. Contrary to results obtained in radio frequency spectroscopy of alkali fermionic atoms, optical spectroscopy of 87 Sr and 171 Yb has...
We present the status of our new experiment to lasercool linear chains of 172Yb+ and 115In+ ions for an optical clock based on the 1S0-3P0 transition in 115In+. We successfully have trapped and laser-cooled Coulomb crystals of 172Yb+ ions in our new scalable ion trap that are used to characterize the trap and to sympathetically cool 115In+ ions. We could demonstrate an area of more than 65 μm, where...
Two nominally identical ultra-low vibration cryocooled microwave sapphire oscillators are compared. The phase noise of a single oscillator was measured to be −105 dBc/Hz at 1 Hz offset on the 11.2 GHz carrier and is characterized by white frequency noise. The Allan deviation at 1s integration time, with drift removed, is 5.8 × 10−16. Between 0.1 and 100 s, the frequency stability is white frequency...
Coefficient is one of the main factors which results in Rb clock to be as second frequency standard. Coefficient is from frequency shift mechanisms because of RF power, intensity of lamp light and collision between atoms in absorption cell. However, Rb clock has many advantages in Power dissipation, dimension and cost in comparison with H-maser and Cs beam. This paper shows a traditional Rubidium...
We demonstrate a 10 GHz hybrid oscillator comprised of a phase stabilized optical frequency comb divider and a room temperature dielectric sapphire oscillator. Characterization of the 10 GHz microwave signal via comparison of two independent hybrid oscillators yields a combined phase noise, L(f) = −100 dBc/Hz at a 1 Hz offset and L(f) < −185 dBc/Hz for frequencies > 1 MHz. The associated absolute...
We demonstrate reduced photodetection noise floor of a 10 GHz fiber laser-based photonic microwave generator by using a pulse repetition-rate-multiplier in combination with a modified Uni-Traveling-Carrier (MUTC) photodiode that features high power handling and linearity. This enables a residual phase noise floor of −170 dBc/Hz at 10 GHz, which is a 5–25 dB improvement over earlier results. Photodiode...
Several evaluations of the frequency shifts have been carried out after NIM5 was moved to the new NIM campus at Changping in 2011. The dominate frequency uncertainty was the microwave power related frequency shifts, which was mainly induced by the microwave leakage for NIM5. The experimental results show that fountains are more sensitive to the leakage field below the Ramsey cavity than above the...
We report a high accuracy measurement of the differential static polarizability for the clock transition in a Yb lattice clock, a key parameter for determining the blackbody (BBR) shift of this transition. We further report efforts to determine the 〈6s5d3 D1‖D‖6s6p3 P0〉 reduced dipole matrix element, a critical ingredient in the non-static correction to the BBR shift. In all, we have reduced the largest...
Thin film bulk acoustic wave (BAW) resonators have been the subject of research for many years due to their uses in wireless communications and chemical sensing. Both the steady-state and dynamic temperature characteristics of quartz resonators, such as those used in biosensing, have been studied in the past. Information pertaining to the steady-state temperature characteristics of ZnO BAW resonators...
We demonstrate a new YIG-tuned oscillator (YTO) design based on a planar YIG resonator that supports half-lambda standing spin wave. The fabricated YTO, with a compact size of 6 cm × 5 cm × 4 cm, has an octave tuning range of 2–4 GHz and −100 dBc/Hz phase noise measured at 10 kHz offset from a 3-GHz carrier. The planar YIG geometry makes the YTO design more cost-effective than the YIG-sphere-based...
In general, GEO satellite is used retransmit the signal in two-way time synchronous system. Keeping synchronous motion with earth, the satellite swing slightly, which have effect on the performance of two-way time synchronization. We can analyze the error caused by satellite movement from two aspects, including time synchronization error between stations, and distance difference from stations to satellite...
We study the effect of spin pair interactions in a chip-scale atomic clock of trapped 87Rb. These interactions can be used to inhibit dephasing in a cold atomic cloud. We also simulate the s-wave frequency shifts for fermions. These results are directly applicable to optical lattice clocks.
This work describes various techniques for generation of pure phase and amplitude modulated signals at microwave frequencies. It presents experimental study of a microwave phase modulator with spurious amplitude modulation of the order of 1 ppm.
The system error caused by equipment is the major factor that restricts time synchronization performance between stations. The two-way satellite time and frequency transfer (TWSTFT) is the most accurate time synchronization method that is generally accepted currently. SATRE Modem is the common reference terminal of TWSTFT. When the temperature, carrier power and code pattern change, its reference...
We present line-spacing frequency control of a microresonator-based optical frequency comb by way of mechanical actuation. Using this novel technique, we have achieved a record level of residual stability in the line spacing of 5×10−15 for 1s averaging. This demonstrates the potential of microresonator combs to support clocks with stability derived from optical frequencies. This work has been performed...
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