Université de Neuchâtel

Ramsey spectroscopy in a Rubidium vapor cell and realization of an ultra-stable atomic clock

Gharavipour, Mohammadreza ; Mileti, Gaetano (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

Divers domaines d’application dans l’industrie, les télécommunications, la navigation et l’espace exigent des étalons de fréquence fiables, compacts et performants avec un niveau de stabilité de −14 à 105s (équivalent à <1 ns/jour). Avec la technologie des lasers à semi-conducteurs, la technique du pompage optique par laser a ouvert de nouveaux...

Université de Neuchâtel

Optically-detected spin-echo method for relaxation times measurements in a Rb atomic vapor

Gharavipour, Mohammadreza ; Affolderbach, Christoph ; Gruet, Florian ; Radojičić, I. S ; Krmpot, A. J ; Jelenković, B. M ; Mileti, Gaetano

In: New Journal of Physics, 2017, vol. 19, no. 063027, p. 1-11

We introduce and demonstrate an experimental method, optically-detected spin-echo (ODSE), to measure ground-state relaxation times of a rubidium (Rb) atomic vapor held in a glass cell with buffer-gas. The work is motivated by our studies on high-performance Rb atomic clocks, where both population and coherence relaxation times ( T1 and T2 , respectively ) of the ‘ clock transition...

Université de Neuchâtel

Stability limitations from optical detection in Ramsey-type vapour-cell atomic clocks

Kang, Songbai ; Gharavipour, Mohammadreza ; Affolderbach, Christoph ; Mileti, Gaetano

In: Electronics Letters, 2015, vol. 51, no. 22, p. 1767-1769

In today’s state of the art compact vapour-cell atomic clocks relying on the pulsed Ramsey-type interrogation, optical detection noise is a major limitation to the achievable short-term stability. In this communication, the influence of the optical detection time on the clock’s short-term stability is investigated and a new analytical expression is developed to precisely predict the stability...

Université de Neuchâtel

Demonstration of a high-performance pulsed optically pumped Rb clock based on a compact magnetron-type microwave cavity

Kang, Songbai ; Gharavipour, Mohammadreza ; Affolderbach, Christoph ; Gruet, Florian ; Mileti, Gaetano

In: Journal of Applied Physics, 2015/117//104510/1-5

We demonstrate a high-performance pulsed optically pumped (POP) Rb vapor-cell clock based on a magnetron-type microwave cavity of only 44 cm3 external volume. Using optical detection, an unprecedented 35% contrast of the Ramsey signal has been obtained. Both the signal-to-noise ratio (of 30 000) and the estimated shot-noise limit of 1.7×10-14τ-1/2 are at...