positive phase contrast microscopy

Phase contrast microscopy where the phase plate advances the un-diffracted light relative to the diffracted light by a quarter wavelength (λ/4). Since diffracted light is already retarded by ~λ/4 through interaction with the object, the result is a half-wave phase difference and destructive interference.

Synonyms: positive phase contrast

See also: phase , phase object , phase plate , phase difference , phase contrast microscopy , interference , negative phase contrast microscopy

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Positive and Negative Phase Contrast

This interactive tutorial explores relationships between the surround (S), diffracted (D), and resulting particle (P) waves in brightfield as well as positive and negative phase contrast microscopy.