Pilgun Y. Physical features of informational signal formation in laser differential-phase scanning microscopy

The dissertation is devoted to the problem of interpretation of data measured using differential-phase method with sequential scanning of reflecting and transparent specimens with laser beams. Physical processes occurring in the measurement system are analyzed. Corresponding factors affecting formation of informational signal are analyzed. Conditions for linear dependence between measured phase and object's phase profile are determined. Using linear approximation solution of inverse problem of reconstructing object's phase profile from measured phase samples is proposed. Special cases with nonlinear dependence between measured phase and phase profile of the object are considered. For the case of investigation of lens-like objects the method modification is proposed. The modification allows determining correct optical power of the lens under investigation even for inaccurate placement of the object relative to the system's focus plane. Possibility of phase ambiguity resolution using phase measurements at two different wavelengths is investigated.