Explain basic principle of holography

Holography is a new method of producing a 3D image of a 3Dobject. An ordinary photograph is only a 2D image of a 3D object. The photographic ?eld is resistive only to amplitude variation of the electromagnetic waves and it is not sensitive to point variations. So this photo does not give the phase information of the waves. In 1948, Dennis Gabor introduced a new method to record both amplitude and phase variation of the electromagnetic waves scattered from the object. When it is reproduced, we get a 3D image of 3D object. Hologram is a recorded inference pattern obtained by the object waves and the coherent reference wave