Study of laser-pumped double-resonance clock signals using a microfabricated cell

We present our microwave spectroscopic studies on laser–microwave double-resonance (DR) signals obtained from a micro-fabricated Rb vapor cell. This study focuses on the characteristics and systematic shifts of the ground-state 'clock transition' in ⁸⁷Rb (

<i>F</i>_g = 1, <i>m</i>_F = 0⟩ →

<i>F</i>_g = 2, <i>m</i>_F = 0⟩) used in Rb atomic clocks, and represents a first step toward a miniature atomic clock based on the DR scheme. A short-term clock instability below 2 × 10¹¹<i>τ</i>^−1/2 is demonstrated, staying below 10⁻¹¹ up to <i>τ</i>= 10⁴ s.