The Nonlinear Bio-Imaging Lab, in collaboration with the FAIR CHARM consortium, is developing new nonlinear imaging platforms to meet diverse biological challenges. In this talk, I will present recent results from two complementary systems: the SWIM microscope, designed for deep, label-free imaging, and SLIDE, designed for ultrafast volumetric acquisition.

Using SWIM, we are developing AI-assisted cell detection from THG images of stained histological samples of human skin, and are now extending this approach to unstained ex vivo biopsies as a step toward in vivo 3D skin microscopy. We also apply SWIM to label-free imaging of mucus in lung models, where we visualize mucus volume, structure, and flow behavior without the need for fluorescent tracers.

With SLIDE, we demonstrate detection of stem cells in whole, unfiltered blood. Harmonic nanoparticle-labeled cells are imaged in flow using a diffractive scanning geometry driven by a wavelength-swept FDML laser. AI segmentation and downstream analysis distinguish isolated cells from aggregates, supporting future applications for in vivo tracking of rare cells circulating in the bloodstream.

Both systems are based on parametric excitation of harmonic signals, but differ in optical design and laser source. SWIM uses a tunable femtosecond OPA source (1250–1800 nm) for deep tissue imaging via 3P and THG processes, while SLIDE uses narrowband pulses and diffractive scanning to achieve 40 Hz 3D imaging at subcellular resolution. Together, these platforms broaden the reach of multiphoton microscopy in both depth and speed, from static 3D tissue structure to dynamic processes.