Study of the Interference Color with Nomarski Prism Wedge Angle in a Differential Interference Contrast Microscopy System

• Published in: Photonics Vol. 10; no. 6; p. 678
• Main Authors: Li, Fei, Zhao, Tingyu
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.06.2023
• Subjects: Color; differential interference contrast; Incident light; Interference; Light; Light sources; Microscope and microscopy; Microscopy; Nomarski prism; plane of apparent splitting; Prisms; splitting angle; Wavelengths
• ISSN: 2304-6732; 2304-6732
• DOI: 10.3390/photonics10060678

Differential interference contrast microscopy systems demonstrate the phase (optical path) rather than the amplitude of a sample. Previous studies have usually approximated the optical path difference produced by the Normarski prism. We derive the mathematical expression for the optical path difference produced by the incident light at any position of the Nomarski prism. As a result, the optical path difference introduced by the differential interference contrast microscope can be calculated. Moreover, the optical path difference is linearly related to the position of the incident light. In addition, the differential interference contrast microscopy system uses a composite light source, while previous studies were basically performed at a single wavelength. The standard wavelengths d (656 nm), F (587 nm), and C (486 nm) are taken as examples to analyze the relationship between the interference color change of the observation surface under the superposition of different wavelengths and the prism wedge angle when the prism moves. When the prism moves the same distance, the larger the prism wedge Angle is, the faster the interference color change is. The analysis based on practical considerations in this paper is believed to provide a method for studying Nomarski prisms.