A cavity QED system with defect-free single-atom array strongly coupled to an optical cavity

Abstract We experimentally realize a new cavity quantum electrodynamics (QED) platform with defect-free single-atom array strongly coupled to an optical cavity. The defect-free single-atom array is obtained by rearranging a probabilistically loaded one-dimensional (1D) optical tweezer array with dimensions of $1 \times 40$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>1</mml:mn> <mml:mo>×</mml:mo> <mml:mn>40</mml:mn> </mml:math> . The atom array is enclosed with two cavity mirrors, which compose a miniature optical Fabry-Pérot cavity with cavity length of 1.15 mm. By precisely controlling the position of the atom array, we demonstrate uniform and strong coupling of all atoms in the array with the optical cavity. The average coupling strength between the single atom and the cavity is 2.62 MHz. The vacuum Rabi splitting spectra for single-atom arrays with atom number N changing from 3 to 26 are measured. Thus, the collective enhancement of the coupling strength with ${\sqrt {N}}$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>N</mml:mi> </mml:msqrt> </mml:math> -dependence for multiple atoms is validated at the single atom level. Our system holds significant potential for establishing the foundation of distributed quantum computing and advancing fundamental research in many-body physics.