Lecture 39

Spatial Coherence and Holography

Honors talks this evening….

Spatial Coherence

Transverse Modes

The 00 mode is the smallest….

Modes and phases

Only the TEM00 mode is fully spatial coherent

Spatial Coherence II

Any spatial mode can be described as a linear combination ofthe various transverse modes

00 01 10 11 ....modeT aTEM TEM TEM Tb EMc d

Spatial Mode Filtering

Slit only wide enough to allow 00 mode To propagate….

Speckle

Wavefront correction

Simple Photography uses only amplitude

Picture looks ‘flat’.

Reason is, we have lost information (i.e. phase)

Two beam interference

Holography

HolographyVirtual Image

Reconstruct 3D view with the phase

Zone Plates revisited

2D Fourier transformEquals a small spot

Phase contrast imaging

3D view of red blood cell…