Cylindrical wave-based off-axis digital holography with long field of view.

Abstract

We present a new, to the best of our knowledge, type of off-axis digital holographic imaging method with a long field of view (FOV). In the method, the pre-magnification recording geometry is realized by a cylindrical lens (CL) or cylindrical beam instead of a conventional objective or spherical beam in traditional off-axis digital holography (DH). At the same time, the reference beam is replaced by a divergent cylindrical beam. Theoretical analysis and experiments have justified that, in off-axis DHs, the adoption of the cylindrical beams can realize a one-dimensional pre-magnification of the object beam only in the off-axis direction to satisfy the bandwidth constraint, and at the same time the FOV of the reconstructed image in the orthogonal direction can remain unaffected. In comparison with existing off-axis DHs, this cylindrical wave-based DH (CWDH) method has a distinct advantage in expanding the FOV of the reconstructed image. The FOV feature of the CWDH makes it especially suitable for applications that require a long FOV such as imaging samples in microfluidic channels.