Extended Data Fig. 2: Sample and measurement technique.
From: Light-field control of real and virtual charge carriers
a, Scanning electron micrograph of the gold–graphene–gold heterostructures with various electrode distances. The yellow colouring indicates the gold electrodes. Insets, total photocurrent as a function of the focal position inside the dashed regions (E0 = 0.3 V/nm). For all measurements and unless otherwise stated, the laser spot was positioned in the centre of the graphene strips such that the total photocurrent is 0. b, Schematic diagram of the measurement scheme. The induced residual current is amplified by transimpedance amplifiers and detected by a dual-phase lock-in amplifier.
