Adjustable super-resolution microscopy with diffractive spot array illumination

Diffractive super-resolution spot arrays offer the possibility of adjustable super-resolution microscopic imaging. By inserting a phase-only diffractive optical element (DOE) into the illumination system of a standard microscope, super-resolution information of the sample can be obtained by spots. Here, we report an adjustable super-resolution microscopy (ASM) that the imaging resolution and the number of spot arrays can be adjusted by DOEs. The results of 3x3 and 5x5 spot arrays with 50% and 70% of the Airy spot size are, respectively, realized to support the flexibility of the ASM. The resolution test target was used as a sample to show the ASM can achieve about double-resolution experimentally, illuminated by a uniform 3x3 spot array with 50% of the Airy spot size under a small numerical aperture objective. Moreover, imaging of cellular mitochondria was performed, substantially realized resolution beyond the diffraction limit. The ability to adjust the super-resolution of microscopy using DOEs is of great importance for further nanoscale imaging.