A scanning microinterferometer with correction of errors caused by overlapping 'ghost' images

Area of Science:

• Optical microscopy
• Interferometry
• Metrology

Background:

• Jamin-Libedef interference microscopes can suffer from ghost image artifacts.
• These artifacts introduce errors in optical path difference (OPD) measurements.
• Accurate OPD measurements are crucial for analyzing transparent specimens.

Purpose of the Study:

• To develop and validate an experimental setup for correcting ghost image errors.
• To enhance the accuracy and reliability of Jamin-Libedef interference microscopy.
• To enable precise OPD measurements of biological and material samples.

Main Methods:

• A novel scanning and integration method was implemented.
• A reference field was scanned to store OPD values.
• Object OPD was calculated by combining measurement results with reference field data.
• Measurements were validated using Sepharose beads, Hela cells, and a microinterference refractometer.

Main Results:

• The experimental setup successfully corrected ghost image errors.
• A significant reduction in measurement error was observed compared to standard methods.
• Measurements showed a difference of approximately 10% with and without ghost image correction.
• High reproducibility was achieved, with a standard deviation of 1.1% in repeated measurements on the same cell.

Conclusions:

• The developed setup effectively mitigates ghost image artifacts in Jamin-Libedef interference microscopy.
• This method significantly improves the accuracy of optical path difference measurements.
• The technique is applicable to various samples, including biological cells and optical instruments.