Current Research

Teaser figure
A single upconverting nanoparticle. Upconverting and Avalanching Nanoparticles are inert, ceramic nanoparticles that are doped with rare-earth lanthanides. As visualized here by a graphic, a single nanoparticle can contain as many as 100+ lanthanide ions, all of which exchange energy to enable photon upconversion.

Upconverting and Avalanching Nanoparticles

Lanthanides are everywhere. They exist in your handheld devices, LIDAR electronics, and pretty much anything that contains a laser. What makes them fascinating optical materials to study is that they simply have lifetimes extending into the microseconds, making them excellent optical gain materials for lasing. In particular, upconverting nanoparticles have been designed to take advantage of these long lifetimes and uses them to excite higher level electrons in their 4f orbitals. A series of energy transfer exchanges between several lantahnides and their excited states within the nanoparticle enable upconversion, a process where the absorption of two sequential photons lead to the emission of a single, higher-energy photon. In doing so, these upconverting nanoparticles can 'upconvert' low-energy infrared photons into higher-energy visible photons for imaging applications. Currently, avalanching nanoparticles (ANPs), poised as a next-generation nonlinear material, can not only upconvert, but also release >2 visible photons (and up to 30 even!) at the same instance, making them one of the most nonlinear nanomaterials to-date. Currently, I am studying the magneto-dependent photoluminescence behavior of ANPs, including their potential applicability in magnetometry and quantum sensing.

Teaser figure
High-resolution nano-optical imaging of a single monolayer MoS2. Monolayer transition metal dichalcogenides, such as MoS2, are often 10-50um in lateral sizes. However, imaging materials smaller than 1um is non-trivial. Nano-optics allows material as small as 10um to be visualized with nanometer resolutions.


Nano-optics has recently emerged as an exciting imaging modality to probe nanoscale materials. In particular, I am interested in the development of other relatively unexplored nano-optical techniques, such as nano-second harmonic generation and nano-photocurrent mapping. In the far-field, second harmonic generation has already been demonstrated to be sensitive to crystal orientation and structure. Pursuing nano-second harmonic generation with nano-optics will likely enable the understanding local strain/symmetries in delicate 2D material systems that are theorized to host intricate correlated-electronic phenomena. Also, unlike fair-field photo-current mapping, other modalities such as nano-photocurrent mapping will also be critical in understanding local electrostatic forces at the nanoscale.

Teaser figure
Carefully tailored toroidal structure design can tune the metamaterial system's optical response. Here, a toroidal resonator has a mode profile that contains an enhancement in the in-plane E-field, and an out-of-plane B-field. Careful metamaterial design can be used in a atonishing ways, for e.g. coupling light to weakly-emitting materials.


A rapidly developing research area, metamaterials are bound to play unexpected roles in technology in the 21st century. Among the many are: improving medical imaging resolution through the metamaterial-modulation of the point spread function, integration with AR/VR for holographic displays, and enhanced photo-generation in photovoltaics. Here, I am interested in the tailoring and coupling of metamaterials to enhance the properties of nanomaterials.

Teaser figure
Ultrafast pump-probe spectroscopy can be used to visualize the demagnetization dynamics of CrI3. Correlated systems often host a plethora of exotic quasi-particles and metastable states that have short lifetimes (picoseconds).

Ultrafast Spectroscopy

Ultrafast spectroscopy allows scientists such as myself to understand the temporaly dynamics of a material system with temporal resolutions down to picosecond timescales. In particular, I am interested in exploring more ways in how THz spectroscopy (a subset of ultrafast) can drive material dyanmics so that one may acuqire all-optical control of nanomaterial systems.

Previous Research

Self-assembled and H2O-tunable structures from polymeric ionic liquids
PVD growth of ternary, low bandgap semiconductors, ZnSnSb2