Abstract
The presence of the auto correlation and twin cross correlation noises restrict the available spatial bandwidth of the holographic microscopy to much less than the available bandwidth of the digital sensor. Therefore, in order to record the same image area as conventional 2D intensity imaging techniques, several images should be taken. We present two-step phase-shifting off-axis digital holography with maximum space-bandwidth product for three-dimensional (3D) digital holography. Removing the autocorrelation term using a two-step phase-shifting technique significantly increases the available bandwidth for off-axis interferometry. An optimizing super-diagonal two-dimensional (2D) spatial frequency sampling scheme at the sub-Nyquist frequency is employed for performing off-axis interferometry in the absence of the autocorrelation term. The spatial bandwidth of the proposed two-step phase-shifting technique is 400% of that in square scheme off-axis digital holography. Experimental results demonstrate the feasibility of this technique in extracting the 3D morphology of transparent microscopic objects with a larger bandwidth.
Highlights
Digital holographic and interferometric microscopy have become promising technologies for generating threedimensional (3D) topographic information of live cells and nano-scale structures [1], [2]
Process dramatically decreases the space-bandwidth product of the digital holography; on the other hand, increasing the sampling rate is an important problem because there are strong physical barriers for the current technologies to increase the pixel number with a constant frame rate
These images were obtained only once before starting the experiment to remove the optical path length difference caused by the optical components and background noise
Summary
Digital holographic and interferometric microscopy have become promising technologies for generating threedimensional (3D) topographic information of live cells and nano-scale structures [1], [2] Both the amplitude and phase of the waves scattered from samples can be obtained by these methods, and the phase information can be used to reconstruct the geometry or compositional structure of transparent objects without requiring an additional labeling process [3]–[5]. Phase-shifting digital holography has played an important role in extracting object phase information from the light intensity measured by a digital camera [6]–[9] This technique requires four interferograms, which are sequentially or simultaneously recorded. An additional estimation or measurement for the reference field is usually adopted to decrease errors in the retrieved phase of the object [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
