Extended Data Fig. 7: Novel photodetector designs based on the APTE.

(a) Geometry for enhanced Shockley-Ramo collection of bulk APTE photocurrents. We choose the contact configuration to maximize the dot product between ∇ψ, shown as the streamlines, and J_ph due to the APTE in the center of the device. An array of such individual pixels could potentially be used for imaging applications in the mid-infrared or terahertz wavelengths. (b) Simulated I_global as a function of the incident beam position for the design in a). The beam size is shown as the green circle and can be realized with an attached microlens. (c) Single-chip, four-quadrant APTE photodetector based on sign-switching, crystal-axes-aligned APTE photocurrents. Photocurrents I₁₃, between contacts 1 and 3, or I₂₄, between contacts 2 and 4, are alternatively measured with the other contact pair floating. The modeled beam size is shown as the green circle. The material and beam properties are the same between designs shown in b) and c), which allows a comparison of the amplitude of I_global. (d) The binary pair corresponding to the signs of I₁₃ and I₂₄ uniquely identifies on which quadrant of the detector the beam is incident. The orientation of the crystal a/b-axes for each design is diagrammed.