Abstract
Simulations were conducted to explore a broader collection of possible illumination patterns realizable using a white-light-emitting hemispherical digital condenser. Several simple, but practical, illumination patterns were selected and used in experiments where a sample was illuminated simultaneously from different directions. The illumination-direction multiplexing (IDM) Fourier ptychographic microscopy (FPM) method was successfully used for imaging and phase recovery. This study suggests that IDM-FPM can be used for imaging photonic crystals with subwavelength periods using traditional microscope condensers with variable numerical aperture. (C) 2017 Optical Society of America