Characterization of the reference wave in a compact digital holographic camera.

Area of Science:

• Optics and Photonics
• Digital Holography
• Wavefront Sensing

Background:

• Holographic reconstruction relies on precise knowledge of the reference wave.
• Traditional methods struggle with divergent reference waves in compact digital holographic cameras.
• Lensless designs, while compact, often deviate from ideal Fourier holographic principles.

Purpose of the Study:

• To develop a technique for determining mathematical parameters of a strongly divergent reference wave from a fiber source.
• To enable high-fidelity digital hologram reconstruction in a novel compact camera design.
• To overcome limitations posed by large numerical apertures and inexact Fourier relationships.

Main Methods:

• Utilizing a new compact digital holographic camera with a lensless, Fourier-hologram-like design.
• Recording quasi-planar object waves at various incidence angles using a Dammann grating.
• Employing an optimization process to identify reference wave parameters for stigmatic imaging.

Main Results:

• Successfully characterized the mathematical parameters of a divergent fiber-based reference wave.
• Demonstrated the ability to reconstruct stigmatic images irrespective of the object wave's angle of incidence.
• Validated a technique applicable to compact digital holographic systems with large numerical apertures.

Conclusions:

• The developed technique accurately characterizes complex reference waves for digital holography.
• This method facilitates high-quality holographic reconstructions in novel, compact camera designs.
• The approach overcomes challenges associated with non-paraxial conditions in lensless holographic systems.