Fig. 1. Flow chart of finite element ray tracing method

Fig. 2. Verification of finite element ray tracing method. (a) Comparison of RMS radii obtained by linear, quadratic and cubic finite element ray tracing with theoretical ones; (b) comparison of RMS radii obtained by cubic finite element ray tracing and theoretical ones at different focal depths behind lens

Fig. 3. Spot diagrams of square aperture microlens with fillet radius of 6 μm after cubic finite element ray tracing

Fig. 4. Square aperture microlenses with different fillet radii. (a) 0 μm; (b) 6 μm; (c) 10 μm; (d) 14 μm

Fig. 5. Spot diagrams of square aperture microlenses with different fillet radii. (a) 0 μm; (b) 6 μm; (c) 10 μm; (d) 14 μm

Fig. 6. Energy concentration curves of square aperture microlenses with different fillet radii