Fourier ptychographic microscopy utilizing chromatic aberration for extended depth of field

Fourier ptychography microscopy (FPM), an imaging technique, can be used to obtain high-resolution images over a wide field of view (FOV). Improving the depth of field (DOF) of FPM enables 3D-sample measurements, thereby broadening its application range. Therefore, this study proposes a method incorporating chromatic aberration. Multi-array LED used in FPM can emit light at three wavelengths. If an objective lens that can cause chromatic aberration at these wavelengths is configured, implementing an FPM system with three focal lengths is feasible. An FPM system with a large DOF can be configured by combining a multi-focal-plane FPM with the digital wavefront correction algorithm of an existing FPM capable of correcting defocus aberration. To verify this, an objective lens system wherein focal points are formed at the desired points by chromatic aberration is designed, its performance is analyzed, and the formation of the three focal lengths by chromatic aberration is experimentally verified by combining the three lenses.