Light off-axis digital holographic detection device

The invention provides a digital holographic microscopic detection device based on a light off-axis two-step subtraction method. The detection device comprises a 620nm LED light source, a collimating and beam expanding system composed of a microscope and a pinhole diaphragm, a polarization element, a first convergent lens, a beam splitter prism, a plane mirror, a microscope objective 1, a second lens, a microscope objective 2, a light intensity attenuation sheet, an objective table and a mechanical micro-displacement table. The method comprises the following steps: dividing incident light into reference light and object light by using a beam splitter prism; the reference light irradiates the plane mirror and is reflected, and the object light irradiates the measured object with the focus placed and is reflected. And after passing through the convergent lens, the CCD acquires data and transmits the data to a computer to calculate and obtain the phase distribution of the object. During calculation, the object h