Fig. 1. Metasurface-enhanced infrared photothermal microscopy integrated with intensity diffraction tomography. (a) Conceptual 3D schematic of the MEIP system incorporating multi-angle visible laser probe illumination and IDT for volumetric reconstruction of photothermal signals. (b) Zoomed view of the sample region, highlighting the interaction of the IR pump and visible probe beams with the nanoantenna metasurface, along with the corresponding layered tomographic reconstruction of photothermal absorption-induced refractive index changes.