Compact high-performance continuous-wave double-resonance rubidium standard with 1.4 × 10&lt;sup&gt;−13&lt;/sup&gt; &amp;#x003C4;&lt;sup&gt;−1/2&lt;/sup&gt; stability

Bandi, Thejesh; Affolderbach, C.; Stefanucci, Camillo; Merli, F.; Skrivervik, Anja K.; Mileti, G.

doi:10.1109/tuffc.2013.005955

Cited by 79 publications

(95 citation statements)

References 25 publications

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“…This greatly suppresses the quartz's fractional frequency instabilities to the 10 À12 to <10 À14 range (timing accuracies of 0.1 ls to <1 ns, respectively) over timescales up to one day. During the last decade, thanks to the employment of laser optical pumping, important advances were made in vapor-cell Rb atomic clocks based on the double-resonance (DR) scheme, using both the continuouswave (CW) 7 and the pulsed optical pumping (POP) interrogation (Ramsey scheme), 8,9 where the pulsed Ramsey scheme is of particular interest for highly compact and high-performance Rb cell clocks. In all types of DR atomic clocks, the microwave resonator cavity is a critical component for applying the microwave field to the atoms in a well-controlled geometry.…”

Section: à13mentioning

confidence: 99%

Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

Affolderbach

Moreno

Иванов

et al. 2018

Applied Physics Letters

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Additive manufacturing (AM) of passive microwave components is of high interest for the costeffective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrated microwave resonator cavities manufactured by AM, in view of their applications to high-performance compact atomic clocks. The microwave cavities employ a loop-gap geometry using six electrodes. The critical electrode structures were manufactured monolithically using two different approaches: Stereolithography (SLA) of a polymer followed by metal coating and Selective Laser Melting (SLM) of aluminum. The tested microwave cavities show the desired TE 011 -like resonant mode at the Rb clock frequency of %6.835 GHz, with a microwave magnetic field highly parallel to the quantization axis across the vapor cell. When operated in an atomic clock setup, the measured atomic Rabi oscillations are comparable to those observed for conventionally manufactured cavities and indicate a good uniformity of the field amplitude across the vapor cell. Employing a time-domain Ramsey scheme on one of the SLA cavities, high-contrast (34%) Ramsey fringes are observed for the Rb clock transition, along with a narrow (166 Hz linewidth) central fringe. The measured clock stability of 2.2 Â 10 À13 s À1/2 up to the integration time of 30 s is comparable to the current state-of-the-art stabilities of compact vapor-cell clocks based on conventional microwave cavities and thus demonstrates the feasibil-ity of the approach.Compact microwave atomic clocks 1 based on alkali vapor cells 2,3 are widely employed as stable frequency references in numerous applications, ranging from telecommunication networks 4 to onboard clocks in satellite navigation systems. 5,6 In such atomic clocks, the frequency of a quartz local oscillator is stabilized to an inherently stable microwave transition in an alkali atom vapor held in a vapor cell. This greatly suppresses the quartz's fractional frequency instabilities to the 10 À12 to <10 À14 range (timing accuracies of 0.1 ls to <1 ns, respectively) over timescales up to one day. During the last decade, thanks to the employment of laser optical pumping, important advances were made in vapor-cell Rb atomic clocks based on the double-resonance (DR) scheme, using both the continuouswave (CW) 7 and the pulsed optical pumping (POP) interrogation (Ramsey scheme), 8,9 where the pulsed Ramsey scheme is of particular interest for highly compact and high-performance Rb cell clocks. In all types of DR atomic clocks, the microwave resonator cavity is a critical component for applying the microwave field to the atoms in a well-controlled geometry. In view of practical applications, this microwave cavity should be small and light-weight and feature simple and fast assembly. In DR atomic clocks, such cavities are generally manufactured by conventional subtractive precision machining of metals, often followed by time-consuming assembly steps requiring precise positioning or ali...

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Section: à13mentioning

confidence: 99%

Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

Affolderbach

Moreno

Иванов

et al. 2018

Applied Physics Letters

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“…The cavity was engineered in order to accommodate a significantly enlarged vapor cell (up to 25 mm in diameter), which is possible because of the high FOF ≈85% as experimentally confirmed in [14]. The short-term stability of a clock based on this cavity was reported to be 1.4 × 10 213 t 21/2 in continuous interrogation mode [20].…”

Section: V L O O P -G a P G E O M E T R Ymentioning

confidence: 99%

Design of atomic clock cavity based on a loop-gap geometry and modified boundary conditions

Иванов

Affolderbach

Mileti

et al. 2017

Int. J. Microw. Wireless Technol.

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In this study, we investigate a concept that can be used to improve the magnetic field homogeneity in a microwave cavity applied in a novel, high-performance atomic frequency standard. We show that by modifying the boundary conditions in the case of a loop-gap geometry, a good improvement of the field homogeneity can be obtained. Such a design demonstrates high potential to improve the frequency stability; it is compact and hence suitable for a future generation of compact, highprecision frequency standards based on vapor cells and a pulsed optical pumping (POP) regime (POP atomic clocks).Keywords: Passive components and circuits, RFID and sensors I . I N T R O D U C T I O NSynchronization and time keeping have a crucial role in the modern world with ever-increasing number of applications, which require frequency stabilities that are beyond the limits of currently employed quartz oscillators: telecommunication applications, smart grid power networks, global positioning systems, high-frequency trading to name a few. Traditionally, frequency standards based on vapor cells and double resonance are recognized as excellent solutions when highfrequency stability needs to be combined with compactness [1]. Their performance is roughly between the large-scale laboratory clocks [2] or commercial Cs clocks [3] and the quartz oscillators widely employed in end-user products [4]. This type of clocks have been steadily improved in the last decades resulting in commercial products that today reach fractional frequency instability of few 10 215 (in terms of Allan deviation), over time scales (integration time) t ≥ 10 4 s [5]. Recently, a new generation of vapor-cell clocks based on pulsed optical pumping (POP) achieved state-of-the-art long-term stability [5] in laboratory conditions. Generally, the microwave cavity has an important role in the operation of vapor-cell clocks and has been in the focus of serious study. For the case of the pulsed clock, the magnetic field homogeneity plays a central role in limiting the performance [6], and hence the cavity needs to be engineered accordingly. In the following study, we address this challenge and investigate a possible solution based on a combination of a loop-gap structure and modified boundary conditions (BCs). Such a cavity design is found to be capable of improving the magnetic field homogeneity while still being very compact.The organization of the paper is the following: In Section II, we include a brief description of the main principle behind the operation of the clock in the context of POP. In Section III, we discuss how the cavity design is linked to the performance of the clock. Next we introduce figures of merit related to the efficiency and the homogeneity and discuss general design guidelines assuming the canonical case of a cylindrical cavity. The loop-gap geometry is introduced in Section IV. In Section V, the modified BCs are discussed in relation to cavity applications. In Section VI, we take into account the whole complexity of the problem and propose a suitable...

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“…The present stability of vapor cell atomic clocks used in Galileo program are 5 × 10 −12 at 1 s [1]. A number of innovative schemes for compact clock based on the double-resonance technique [5], pulsed optical pumping and microwave interrogation [6,7], or coherent population trapping [2,3], are showing performances at the level of hydrogen maser. The project presented here describes a compact atomic clock laboratory prototype which uses an original atoms interrogation technique called coherent population trapping (CPT) [8].…”

Section: Introductionmentioning

confidence: 99%

Atomic clock using coherent population trapping in a cesium cell: frequency stability and limitations

Mejri¹,

Tricot²,

Danet³

et al. 2016

J. Phys.: Conf. Ser.

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Compact high-performance continuous-wave double-resonance rubidium standard with 1.4 × 10<sup>−13</sup> τ<sup>−1/2</sup> stability

Cited by 79 publications

References 25 publications

Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

Design of atomic clock cavity based on a loop-gap geometry and modified boundary conditions

Atomic clock using coherent population trapping in a cesium cell: frequency stability and limitations

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