Simultaneous Multifocal Plane Fourier Ptychographic Microscopy Utilizing a Standard RGB Camera

Area of Science:

• Optics and Photonics
• Computational Imaging
• Materials Science

Background:

• Fourier ptychographic microscopy (FPM) enables high-resolution, large-area imaging across various scientific fields.
• Existing FPM techniques can be limited in capturing information from multiple depths simultaneously.
• The wavelength-dependent focal length variation in optical systems is a known physical principle.

Purpose of the Study:

• To enhance Fourier ptychographic microscopy (FPM) by integrating multifocal plane imaging.
• To achieve simultaneous acquisition of images from multiple focal planes within a single measurement.
• To improve the depth-of-field and information content of FPM.

Main Methods:

• Utilized an RGB light-emitting diode (LED) array for sample illumination.
• Captured raw images using a color camera.
• Separated R, G, and B channels from raw images to extract distinct focal plane information, leveraging wavelength-dependent focal length variation.
• Employed a single aspherical lens (NA 0.15) as the objective lens and an illumination NA of 0.08 for FPM reconstruction.
• Achieved a synthetic NA of 0.23 for simultaneous multifocal plane FPM.

Main Results:

• Successfully extracted three focal plane images from a single raw image capture.
• Demonstrated simultaneous imaging of individual organic light-emitting diode (OLED) pixels and the encapsulating glass substrate surface.
• Validated the multifocal imaging performance of the enhanced FPM system on a transparent OLED sample.
• Achieved a synthetic numerical aperture (NA) of 0.23, enhancing imaging capabilities.

Conclusions:

• The enhanced FPM system effectively integrates multifocal plane imaging for simultaneous depth-resolved analysis.
• This technique offers a significant advancement for high-resolution, large-area imaging applications, particularly in microelectronics and materials inspection.
• The single-shot, multifocal acquisition method streamlines imaging processes and provides richer datasets.