Time-decorrelated multifocal array for multiphoton microscopy and micromachining

We demonstrate a temporally decorrelated, multifocal multiphoton microscope. Using an etalon, we split the 800-nm light from either an ultrashort-pulsed $\mathrm{Ti}:{\mathrm{Al}}_2{\mathrm{O}}_3$ oscillator or a $\mathrm{Ti}:{\mathrm{Al}}_2{\mathrm{O}}_3$ regenerative amplifier into an array of beamlets that are delayed with respect to one another in time. The collimated beams overlap at slightly different input angles at the entrance pupil of a 1.25-numerical aperture oil-immersion objective to produce an array of foci that are temporally decorrelated at the focal plane of the objective. The temporal decorrelation eliminates any interference among the foci and permits multifocal multiphoton imaging with the resolution of single-point illumination.