Versatile spectral modulation of a broadband source for digital holographic microscopy

Area of Science:

• Optical microscopy
• Metrology
• Photonics

Background:

• Digital holographic microscopy (DHM) typically uses broadband sources.
• Controlling the spectral properties of these sources is crucial for advanced applications.
• Existing methods for spectral control can be complex or limited in versatility.

Purpose of the Study:

• To demonstrate the use of spatial light modulators (SLMs) for spectral control of broadband sources in DHM.
• To adapt the source bandwidth and wavelength for specific imaging and measurement tasks.
• To showcase applications in quantitative phase imaging and topographic measurements.

Main Methods:

• Implementing SLMs in a 'pulse-shaping' configuration.
• Utilizing SLMs for versatile control over light source bandwidth and wavelength.
• Applying spectral control for off-axis DHM and hierarchical optical phase unwrapping.

Main Results:

• SLMs provide effective spectral control over broadband sources for DHM.
• Quantitative phase imaging across the entire field of view was achieved by adapting source bandwidth.
• Accurate topographic measurements of structures up to 50 µm were obtained using wavelength-sequenced phase unwrapping.

Conclusions:

• SLMs are a powerful tool for spectral manipulation in DHM.
• This technique enhances DHM capabilities for diverse experimental needs.
• SLM-based spectral control enables high-resolution, ambiguity-free metrology of microstructures.