Compressed supercontinuum probe for transient absorption microscopy.

Here, we combine three optical advancements to transient absorption microscopy in order to access the photodynamics in systems requiring stringent spatial and temporal resolution criteria. First, a broadband visible probe is generated by a commercial photonic crystal fiber. Second, a spatial light modulator-based pulse shaper is incorporated to reduce the pulse dispersion and improve temporal resolution. Third, 1.4 numerical aperture objectives for excitation and light collection provide optimal spatial resolution. The result of these improvements is a probe beam that spans 115 nm across the visible region yet maintains a ∼100  fs instrument response at the sample position. We demonstrate the capabilities of this microscope by imaging polystyrene beads in a solution of IR-144 dye, revealing aggregated species at the bead surfaces.