Dual-Hyperspectral Optical Pump-Probe Microscopy with Single-Nanosecond Time Resolution.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spectroscopy

Background:

• Optical pump-probe microscopy (PPM) is crucial for imaging electronic excitations and charge transport.
• Current PPM methods face limitations in time window (nanoseconds) and spectral resolution, restricting the study of slow processes.

Purpose of the Study:

• To introduce a novel dual-hyperspectral PPM setup with an extended time window (nanoseconds to milliseconds) and single-nanosecond resolution.
• To overcome limitations of existing PPM techniques for studying slow dynamic processes in materials.

Main Methods:

• Developed a dual-hyperspectral PPM system with a wide-field probe (370-1000 nm) and broad pump (330 nm to 16 μm).
• Applied the technique to study two-dimensional metal-halide perovskites (2D-MHPs) using both electronic and vibrational pump excitations.
• Achieved single-nanosecond temporal resolution for imaging transient responses.

Main Results:

• Spatially and temporally resolved images revealed insights into heat dissipation, film uniformity, impurity phases, and interfaces in 2D-MHPs.
• Demonstrated imaging of in-plane strain wave propagation in 2D-MHP single crystals.
• The method provides extensive spectral tunability and improved time resolution.

Conclusions:

• The enhanced dual-hyperspectral PPM technique significantly advances the study of slow dynamic processes in semiconductors.
• Opens new avenues for imaging charge carriers, heat transport, and phase transformations in materials with complex properties.
• Facilitates detailed analysis of materials with spatially varying composition, strain, and interfaces.