Fourier ptychographic microscopy using an infrared-emitting hemispherical digital condenser

Area of Science:

• Optics and Photonics
• Microscopy Techniques

Background:

• Fourier ptychographic microscopy (FPM) is a powerful computational imaging technique.
• Near-infrared (NIR) imaging offers unique advantages for certain materials and applications.

Purpose of the Study:

• To demonstrate Fourier ptychographic microscopy in the near-infrared (NIR) spectral range.
• To image periodic patterned samples, specifically photonic crystals, using NIR FPM.

Main Methods:

• Utilized a computer-controlled hemispherical digital condenser with multiple 940 nm LEDs.
• Employed a phase retrieval algorithm for image reconstruction.
• Imaged periodic patterned samples (photonic crystals).

Main Results:

• Successfully demonstrated NIR Fourier ptychographic microscopy.
• Achieved excellent correspondence between experimental and simulated results.
• Determined that resolution for single-period samples is limited by the Rayleigh criteria.

Conclusions:

• NIR FPM is a viable technique for high-resolution imaging.
• The developed system effectively images photonic crystals.
• Rayleigh criteria fundamentally limit resolution in this configuration for specific samples.