Compact all-in-line adaptive optics fluorescence microscope using an optofluidic phase modulator

We demonstrate a completely in-line adaptive optics fluorescence microscope featuring an optofluidic refractive phase modulator at its pupil plane to correct for system and sample induced optical aberrations. To eliminate the need for a wavefront sensor, it estimates optical aberrations directly through the microscope images via a modal decomposition based algorithm that uses spatial frequency content of acquired images as a quality metric. Besides the custom-microfabricated phase modulator, the microscope comprises commercially available components, and can attain a diffraction-limited resolution of 635 nm across the entire field of view at the fluorescence emission wavelength of 485 nm, using a 0.55 NA objective lens.