High numerical aperture Fourier ptychography: principle, implementation and characterization
Fourier ptychography (FP) utilizes illumination control and computational post-processing to increase the resolution of bright-field microscopes. In effect, FP extends the fixed numerical aperture (NA) of an objective lens to form a larger synthetic system NA. Here, we build an FP microscope (FPM) using a 40X 0.75NA objective lens to synthesize a system NA of 1.45. This system achieved a two-slit resolution of 335 nm at a wavelength of 632 nm. This resolution closely adheres to theoretical prediction and is comparable to the measured resolution (315 nm) associated with a standard, commercially available 1.25 NA oil immersion microscope. Our work indicates that Fourier ptychography is an attractive method to improve the resolution-versus-NA performance, increase the working distance, and enlarge the field-of-view of high-resolution bright-field microscopes by employing lower NA objectives.
© 2015 Optical Society of America. Received 17 Nov 2014; revised 5 Jan 2015; accepted 5 Jan 2015; published 4 Feb 2015. This project was funded by the Caltech Innovation Initiative (CI2), Agency Award: 13520135; the National Institute of Health (NIH) Agency Award R01AI6226-01 and Clearbridge Biophotonics (Singapore). We thank Dr. Ana Rodriguez for providing the biological samples and input, Mr. Jinho Kim and Mr. Chao Han for fabricating the 2-hole and 2-slit targets, and Mr. Jaebum Chung for helpful discussions.
Published - oe-23-3-3472.pdf