Fig. 2From: Ultrasonic signal detection based on Fabry–Perot cavity sensorTwo-photon lithography using a 3D direct-laser-writing (DLW) system (Photonic Professional GT, Nanoscribe). a Left: Cross-section of the processed structure. Upper right: End face of the processed structure. b Left: Schematic diagram of the actual machining model. Right: Local enlarged figure in the dotted line box of the left figureBack to article page