The MIIPS method for simultaneous phase measurement and compensation of femtosecond laser pulses and its role in two-photon microscopy and imaging

Abstract

A number of nonlinear imaging modalities, such as two-photon excitation and second harmonic generation, have gained popularity during the last decade. These, and related methods, have in common the use of a femtosecond laser in the near infrared, with the short pulse duration making the nonlinear excitation highly efficient. Efforts toward the use of pulses with pulse duration at or below 10 fs, however, have been a great challenge, in part due to the fact that shorter pulses have been found to cause greater sample damage. Here we provide a brief review of the MIIPS method for correction of phase distortions introduced by high numerical aperture objectives and the introduction of simple phase functions capable of preventing three-photon induced damage, reducing autofluorescence, and providing selective probe excitation.