Infrared Microscopy of Defects

The strain field of dislocations shifts the polarization plane of light. A specimen (with two polished surfaces) between almost crossed polarizers thus transmits more or less light than the bulk around defects
The picture shows two edge dislocations in GaAs parallel to the optical axis. The contrast is directly proportional to the sign and magnitude of the strain field (or stress-field, which is shown for comparison)
 

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go to 6.1.2 Infrared Microscopy

go to Stress Field of an Edge Dislocation

© H. Föll (Defects - Script)