SHG Imaging and the Role of Laser Sources
Second-harmonic generation (SHG) imaging is widely used to investigate non-centrosymmetric materials such as 2D semiconductors, lithium niobate, and biological structures. The technique provides insights into crystal orientation, layer stacking, grain boundaries, and mechanical strain.
In many laboratories, SHG imaging is almost automatically associated with femtosecond laser sources. While powerful, these systems increase experimental complexity and introduce stricter laser safety requirements.
Picosecond Lasers as an Alternative Approach
The poster demonstrates that high-power picosecond pulsed lasers can be used as an alternative excitation source for SHG imaging. Using a confocal microscope setup, SHG signals excited at 1064 nm were recorded together with time-resolved photoluminescence (TRPL), allowing multiple optical contrasts to be measured from the same region of a sample.
Experiments on monolayer MoS₂ and WSe₂ illustrate how reflection images, SHG signals, and lifetime data can be collected within a single microscope configuration.
