Holography
A technique for recording and reconstructing 3D wavefields by recording phase and amplitude interference patterns between object and reference laser beams.
Governing formula
I(x,y) = |E_ref + E_obj|²
SI unit
N/A
In depth
Unlike standard 2D photography which records only light intensity (amplitude), holograms record phase information via coherent laser interference.
Examples in the real world
3D security holograms printed on credit cards, passports, and currency notes.