Spatial Resolution Enhancement in Time Domain via Transient Nonlinearity

Guan-Jie Huang^1*, Hao-Yu Cheng², Kung-Hsuan Lin², Shi-Wei Chu¹

¹Department of Physics, National Taiwan University, Taipei, Taiwan
²Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Guan-Jie Huang, email:eric20031235@gmail.com

The pump-probe technique with its time-resolved property is widely used in probing the carrier dynamics. As a far-field method, diffraction restricts the resolving power in pump-probe microscopy. The current technique based on transient absorption (TA) saturation and a doughnut beam has been demonstrated to overcome the diffraction limit. However, the intense saturation beam may induce sample damage and additional perturbations to the TA signals. Here, we report a scattering-based pump-probe in silicon nanoparticles with transient superlinear pump-dependency via controlling different pump-probe delay. Combining the transient superlinearity with optical microscopy, we demonstrate a 2-fold spatial resolution enhancement (down to 𝜆/4). This technique paves the way towards label-free optical super-resolution imaging in dielectric materials.

Keywords: Pump-probe Microscopy, Silicon Nanoparticles, Superlinear Nonlinearity