Cold atom quantum sensors based on atom interferometry are among the most accurate instruments used in fundamental physics, metrology, and foreseen for autonomous inertial navigation. However, they typically have optically complex, cumbersome, and low-bandwidth atom detection systems, limiting their practical applications. Here, we demonstrate an enabling technology for high-bandwidth, compact, and nondestructive detection of cold atoms, using microwave radiation. We measure the reflected microwave signal to coherently and distinctly detect the population of single quantum states with a bandwidth close to 30 kHz and a design destructivity that we set to 0.04%. We use a horn antenna and free-falling molasses cooled atoms in order to demonstrate the feasibility of this technique in conventional cold atom interferometers. This technology, combined with coplanar waveguides used as microwave sources, provides a basic design building block for detection in future atom chip-based compact quantum inertial sensors.

基于原子干涉术的冷原子量子传感器是基础物理学，计量学中最准确的仪器之一，并且可以预测用于自主惯性导航。但是，它们通常具有光学复杂，麻烦且低带宽的原子检测系统，从而限制了其实际应用。在这里，我们演示了一种利用微波辐射对冷原子进行高带宽，紧凑且无损检测的技术。我们测量反射的微波信号，以相干且清晰地检测带宽接近30 kHz且设计破坏性设为0.04％的单量子态的总体。为了证明该技术在常规冷原子干涉仪中的可行性，我们使用了喇叭天线和自由落体的糖蜜冷却原子。这项技术