Multimodal optical imaging with multiphoton microscopy and optical coherence tomography.

Two types of combined multiphoton microscopy and optical coherence tomography (MPM/OCT) are compared for multimodal optical imaging. Single-scale multiphoton microscopy and optical coherence microscopy (MPM/OCM) is shown to acquire multiple contrasts from MPM and OCT simultaneously. Multi-scale MPM/OCT is shown to provide multiple field-of-views (FOVs), where OCT provides tissue level imaging and MPM provides cellular level imaging. In both types, the MPM includes two channels which are two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). Representative images using each system are demonstrated on biological specimens. A detailed comparison of the two types of MPM/OCT shows that each system has its own pros and cons. MPM/OCM is high-resolution but with limited FOV, and OCM may or may not provide additional information than MPM depending on the samples. Multi-scale MPM/OCT can change FOV but need both low and high NA objectives. For future development, the two types of MPM/OCT can be further integrated to achieve both functions on a single system.