A planar probe for the coupling of ultrasonic signals to a planar component to be tested by means of water-free jet technology is provided. The planar probe includes: at least one preflow chamber; a flow chamber located downstream of at least one preflow chamber, wherein the flow chamber extends through a slot-shaped water outlet opening to a lower surface of the planar probe; a probe, wherein a lateral surface of the probe comprises emitting/receiving elements and forms an inner wall section of the flow chamber; a base body for the reception of the probe; and a sliding plate comprising the slot-shaped water outlet opening, whose planar extension along the component is larger than the planar extension of the base body along the component, wherein the planar probe is connected to the sliding plate.