Single-shot dual-wavelength interferometric microscopy

Interferometric microscopy (IM) can provide complex field information of the biological samples with high spatial and temporal resolution with virtually no photodamage. Measuring wavelength-dependent information in particular has a wide range of applications from cell and tissue refractometry to the cellular biophysical measurements. IM measurements at multiple wavelengths are typically associated with a loss in temporal resolution, field of view, stability, sensitivity, and may involve using expensive equipment such as tunable filters or spatial light modulators. Here, we present a novel and simple design for an interferometric microscope that provides single-shot off-axis interferometric measurements at two wavelengths by encoding the two spectral images at two orthogonal spatial frequencies that allows clean separation of information in the Fourier space with no resolution loss. We demonstrated accurate simultaneous quantification of polystyrene bead refractive indices at two wavelengths.