Dual-Wavelength Image-Plane Digital Holographic Microscopy Based on Bi-Color LED Chips

Dual-wavelength image-plane digital holographic microscopy based on bi-color LED chips is proposed. Firstly, a red LED chip with central wavelength of 670 nm and a green LED chip with central wavelength of 521 nm are packaged as a hemispherical LED chip. Composite holograms at different wavelengths and phase shift are recorded with a color CCD camera. The phase distribution and surface profile of the sample are reconstructed based on the color separation technology, phase shifting technology and dual-wavelength phase extracting technology. The feasibility of the proposed method is demonstrated by the experimental results.