Nonlinear imaging through a Fermat's golden spiral multicore fiber.

We report two-photon lensless imaging through a novel Fermat's golden spiral multicore fiber. This unique layout optimizes the sidelobe levels, field of view, crosstalk, group delay, and mode density to achieve a sidelobe contrast of at least 10.9 dB. We demonstrate experimentally the ability to generate and scan a focal point with femtosecond pulses and perform two-photon imaging.