Date: Thursday, May 16, 2024

Time:  12:00 PM - 1:00 PM MST

Location: PAIS, Room 2540

Speaker:

Dr. Chih-Feng Wang, OSE Alumnus 

Pacific Northwest National Laboratory, Richland, Washington 

Abstract：

Exploring the nano-world beyond diffraction limitations is crucial for understanding the intricate dynamics of light-matter interactions and localized phenomena. Near-field techniques have emerged as powerful tools to address this challenge directly. Tip-enhanced Raman spectroscopy (TERS) stands out among these techniques, providing nanometer-scale spatial resolution to probe the vibrational modes of molecules and unveil their unique chemical fingerprints. While TERS effectively surpasses the diffraction barrier, we are also investigating additional opportunities within near-field techniques under ambient conditions. Our innovative approach involves utilizing scattered photons from the tip as a novel light source in our home-built multimodal nanoscope. This allows for spatially and spectrally resolved investigations across diverse spectroscopic modalities, extending optical nano-imaging capabilities to encompass linear and nonlinear optical responses in materials. These responses include single-photon and two-photon photoluminescence, nano-extinction, second harmonic generation, four-wave mixing, and more, all achieved with ultrahigh spatial resolution. In this seminar, I will discuss the advantage of multimodal hyperspectral nanoscopy, highlighting its potential to explore diverse material properties and phenomena at the nanoscale.

Biography:

Chih-Feng Wang completed his PhD in optical science and engineering at the University of New Mexico in 2019 under the supervision of Dr. Terefe Habteyes. Subsequently, he joined Pacific Northwest National Laboratory (PNNL) as a postdoctoral researcher under the guidance of Dr. Patrick ElKhoury. Currently serving as a Physicist in PNNL's Physical Sciences Division, Chih-Feng specializes in pioneering the development of advanced multimodal hyperspectral micro/nanoscopy techniques. These techniques exhibit exceptional spatial-temporal-spectral sensitivity, particularly in the study of plasmonic nanomaterials and 2D materials. Chih-Feng's research endeavors are dedicated to broadening the capabilities and applications of near-field techniques, with a focus on pushing the boundaries of exploration in the nano-world.