Digital holography leverages amplitude and phase data to reconstruct 3D images, even of optically transparent objects. By capturing interference patterns with specialized equipment like The Imaging Source’s DMK 72BUC02 monochrome industrial camera, researchers can reveal structures invisible to standard imaging techniques. When combined with multispectral imaging—capturing data beyond the RGB range—this approach opens new possibilities for observing and analyzing materials. However, integrating multispectral capabilities into holography presents challenges due to how holographic images are generated.

Experimental Setup: Tunable Acousto-Optic Filters

Recently, researchers introduced a novel experimental digital holography system using an interferometer equipped with an acousto-optic tunable filter (AO) and The Imaging Source’s DMK 72BUC02 camera. Their goal was to enhance the informativeness of digital holography, particularly for transparent objects. This advancement could significantly benefit fields like biomedical imaging or materials testing where observing delicate structures is critical.

How It Works: Capturing Light Wavefronts

Creating a hologram involves splitting coherent light (e.g., from a laser) into object and reference beams, then recording their interference pattern with a camera sensor. Digital holography reconstructs this data to generate quantitative amplitude and phase images. For multispectral holograms, multiple wavelengths must be reconstructed and fused. However, existing systems often limit the spectral range available for imaging.

The authors addressed this limitation by using a broadband light source and an AO filter that can adjust wavelengths dynamically. This allows quasi-continuous spectral tuning without requiring separate coherent light sources for each wavelength. By spatially separating diffraction orders, they achieved off-axis holography capable of capturing Fourier holograms from transparent objects across arbitrary narrow spectral intervals.

Applications in Action

Digital holography’s non-contact nature makes it ideal for delicate applications like bio-medical imaging or materials testing. Its multispectral extension enables simultaneous analysis of amplitude-phase and spectral structures, improving capabilities for observing phenomena such as refractive index fields within transparent media or tracking particle trajectories.

The researchers’ system demonstrates how dynamic spectral tuning can enhance holography’s utility without sacrificing precision. This approach promises to expand applications in fields requiring detailed imaging of delicate or complex materials—advancing microscopy, optical coherence tomography, and non-destructive testing alike.

Last Updated: 2025-09-05 00:53:58