Reflective interferometric system combining low-coherence spectral-domain phase microscopy and wide-field holography for characterization of thin samples

We introduce an integrated system combining low-coherence spectral-domain phase microscopy (SDPM) together with a compact, simple-to-align, wide-field high-coherence interferometer (off-axis TAU module) for accurate quantitative phase measurements. The proposed compact system is capable of capturing an off-axis, wide-field interference in the time domain simultaneously with single-point interference in the spectral domain. The integrated system can obtain both quantitative phase of transparent samples, requiring a reflective surface at the back of the sample, or profiling of reflective samples. Since there are no moving elements in the system, it is capable of measuring static and dynamic samples, while time resolution is limited only by the frame rate of the detectors (a camera and a compact spectrometer). Both interferometers are in common-path geometry, resulting in high signal to noise ratio and nanometer-scale stability. The combined system is ideal for characterization of static or dynamic samples containing both wide areas of interest that can be acquired by the off-axis TAU module, and specific spots of interest requiring fine measurement that can be acquired by SDPM.