Dual Wavelength Lensless Fourier Transform Digital Holographic Microscopy for Quantitative Phase Imaging

Digital holographic microscopy (DHM) is a commonly used technique to obtain quantitative information by measuring the phase shifts in light and changes in refractive index of the sample. Samples having optical thickness greater than the wavelength of light undergo 2π phase ambiguities and the phase gets wrapped. A dual wavelength Lensless Fourier Transform Digital Holographic (LLFTDH) Microscopy has been proposed for quantitative phase imaging of micro structures. LLFTDH Microscopy along with synthetic wavelength technique reduces the computational complexity and has an advantage over the other reconstruction methods. The holograms are recorded at wavelengths 532 nm (green) and 632.8 nm (red). Reconstruction is done at a synthetic wavelength of 3.3μm to obtain the unwrapped phase. The height and spatial resolution of the sample at the synthetic wavelength is calculated as 1.67μm and 8.77μm respectively.