Fig. 1: Design, simulation, and characterization of Pocket MUSE.

a Exploded schematic showing the major components of Pocket MUSE. b 3D rendering and photographs showing samples attached to the microscope through surface tension. c Photograph demonstrating the hand-held operation of Pocket MUSE. d Optical simulation of a small RACL (US7643225B1, f-number = 2.45) stacked on top of a smartphone camera lens (US20130021680A1, f-number = 2.46), showing ~2× magnification (1.5 mm/0.75 mm). e–h Simulated Huygens point spread function (PSF) at the image plane showing the full width at half maximum (FWHM) spot diameter (e) Δy = 0, (f) 0.25, (g) 0.5 and (h) 0.75 mm from the center of the field (simulation FOV: 36.42 × 36.42 µm²). Minimal distortion to the PSF was observed within the center 1 mm diameter FOV. The simulation does not reflect the practical optical resolution of Pocket MUSE, which is higher due to smaller f-numbers (larger NAs). i Image of a USAF-1951 resolution target acquired with a 1/7″ RACL (Largan 40069A1) attached to an iPhone 6s+, showing resolving power up to Group 9 Element 2 (0.87 µm) based on the Sparrow criterion. The middle image is a close-up view of the region in the red box in the original image. The plot on the right represents the normalized intensity profile at the location of the vertical red line. Additional characterization at different locations of the FOV is shown in Supplementary Fig. 4. j Ray tracing simulation of the dual-LED frustrated TIR setup, showing relatively uniform illumination achieved in a 2.5 × 2.5 mm² region at the center of the sample holder. The heat map in the middle indicates the normalized intensity of the square. The plot on the right represents the normalized intensity profile labeled with the vertical line. Intensity variation is within 10% across 3 mm FOV. k Bright-field macro image showing a 2.5 × 2.5 mm² fluorescent phantom on the Pocket MUSE sample holder. l A relatively uniform excitation pattern was achieved with the frustrated TIR illumination configuration, matching the simulation result.