A method for imaging a sample is described. The sample is characterized by a limit on incident optical energy absorbed over a given time period. The method includes providing at least one input optical wave that includes pulses that each have a full-width half-maximum time duration of more than 100 picoseconds and a pulse energy sufficiently large such that a sufficient number of consecutive pulses absorbed by the sample would exceed the limit. The method also includes directing the input optical wave to focus on a first portion of the sample; detecting energy from an output optical wave generated from a nonlinear optical interaction in the first portion of the sample with the input optical wave; and generating a representation of the first portion of the sample based on the detected energy from the output optical wave.