Monolithic integration of binary-phase Fresnel zone plate objectives on 2-axis scanning micromirrors for compact microscopes.

We demonstrated a unique monolithic integration of Fresnel elliptical zone plate (EZP) objective on a 2-axis staggered vertical comb-drive micromirror with 500 μm by 800 μm surface area via direct patterning of reflective binary phase modulation elements on a silicon chip. The need for focusing optics is thus obviated, simplifying the micro-endoscope assembly and improving its form factor. The design of binary phase EZP was guided by simulations based on FFT based Rayleigh-Sommerfeld diffraction model. For dual-axis scanning angles up to 9º by 9º at the image plane, the simulated diffracted Airy disks on a spatial map have been demonstrated to vary from 10.5 μm to 28.6 μm. Micromirrors scanning ±9º (optical) about both axes are patterned with elliptical zones designed for 7 mm focal length and 20þ off-axis 635-nm illumination using 635 nm laser. Videos of samples acquired with ~15 μm lateral resolution over 1mm × 0.35 mm field of view (FOV) at 5.0 frames/second using the device in both transmission and reflectance modes bench-top single-fiber laser scanning confocal microscope confirmed the applicability of the device to micro-endoscopy.