Direct continuous phase demodulation in digital holography with use of the transport-of-intensity equation

A novel approach for continuous phase demodulation in digital holography is proposed. This method allows direct recovery of continuous phase information encoded in digital holography. Transport-of-intensity-equation is invoked following the numerical reconstruction and propagation of the digital hologram. The recovered phase is free from the 2π discontinuities and thus phase unwrapping problems are avoided. Furthermore, it provides a new way to eliminate the tilt and quadratic phase aberration inherent in digital holography without cumbersome physical or digital compensation procedure. The performance and feasibility of the method are demonstrated through two applications in micro-optics and bio-imaging.