Two-channel algorithm for single-shot, high-resolution measurement of optical wavefronts using two image sensors

Abstract

We propose a two-channel holographic diversity interferometer (2ch-HDI) system for single-shot and highly accurate measurements of complex amplitude fields with a simple optical setup. In this method, two phase-shifted interference patterns are generated, without requiring a phase-shifting device, by entering a circularly polarized reference beam into a polarizing beam splitter, and the resulting patterns are captured simultaneously using two image sensors. However, differences in the intensity distributions of the two image sensors may lead to serious measurement errors. Thus, we also develop a two-channel algorithm optimized for the 2ch-HDI to compensate for these differences. Simulation results show that this algorithm can compensate for such differences in the intensity distributions in the two image sensors. Experimental results confirm that the combination of the 2ch-HDI and the calculation algorithm significantly enhances measurement accuracy.

Internal Inspection of Micro Deep Drawing Parts using Digital Holography

“…In case that the piezoelectric device is not able to work properly inside a turbulent environment, the setup mentioned in Fig. 1 can be extended with the Two-Frame-Phaseshifting-method [5] to capture two phase-shifted holograms using two CCDs at the same time.…”

“…Thus DHM qualifies well for the fast and precise inspection of the inner of micro parts. Additionally DHM was shown to be used in a single exposure recording with the help of Two-Frame-Phase Shifting [5], making DHM very robust and applicable in a production line. A major problem for DHM is the occurrence of ambiguities when the roughness of the observed object is greater than half of the used wavelength.…”

Highly accurate spatial mode generation using spatial cross modulation method for mode division multiplexing

“…Then, the SCM image was displayed onto the PSLM. After that, the complex amplitude distribution of the reconstructed light was measured by holographic diversity interferometry (HDI) 13,14 , which is one of the phase-shifting digital holography. Figure 6 shows the experimental results.…”

Quality Control and Characterization

“…This is accomplished by using circular polarized light from the object and linear polarized light from the reference mirror. Nozawa et al have already used this system for single-shot and highly accurate measurements of complex amplitude fields with a simple optical setup [Noz15].…”