Fig. 4.

Dynamic wavefront distortions over a 4 mm pupil diameter in the 15.1 kHz resonant scanner operating at 4.9° across the sinusoidal wave are shown in (a). The total wavefront distortions are shown in (b), and oblique astigmatism subtracted wavefronts in (c). The plots of the variation of wavefront RMS, Zernike coefficients, Strehl ratio (at 680 nm) and increase in the FWHM of the PSF (at 680 nm), across the field of view, are shown in (d)–(g). Additional curves in (f) and (g) using dashed lines show the theoretical Strehl ratio and PSF FWHM predicted if oblique astigmatism was corrected. The green shaded region in (f) satisfies the Maréchal criterion. The inset diagrams in (g) show PSFs at three different scanner mirror orientations.