Single-shot digital holography separating the real and imaginary parts of a signal beam in the rhombic region of the Fourier plane

We propose a new single-shot digital holography that measures the complex amplitude high precisely using a single image sensor. In this technology, a signal beam passes through a diamond-shaped low-pass filter, and a reference beam passes through a chessboard pattern phase-shift plate, where the phase difference between adjacent pixels is π/2. The signal and reference beams interfere, and the interference fringe is captured by a single image sensor. In a computer, an image is acquired by extracting the phase-dependent component from the interference fringe. The real and imaginary parts were obtained separately from the inside and outside of the diamond shape in the Fourier plane of the acquired image, respectively. Subsequently, the real and imaginary parts were combined to reconstruct the complex amplitude. This method can obtain the signal light in the diamond-shaped band of the Fourier plane, where the information of the signal light is concentrated generally, so this method can measure high precisely. Numerical analysis showed that the signal-to-noise ratio of the intensity and phase of this method were more than 4.8 and 2.8 dB higher, respectively, than two-step parallel phase-shift digital holography, and more than 7.3 and 4.8 dB higher, respectively, than Fourier fringe analysis, an off-axis digital holography technique. Moreover, the range of the reference intensity that maintains high-precision measurements was clarified, and the reconstruction accuracy against noise in the interference fringe or reference beam intensity was investigated.