Synopsis: My previous research experience mainly focuses on laser-matter interactions and their applications, especailly for manufacturing purposes.

Direction 1: 3D inscription deep inside semiconductor materials

Topic: 3D inscription deep inside semiconductor materials

Introduction: Silicon is a material with narrow bandgap and large nonlinear refractive index. The electrons can be easily excited, leading to strong defocusing and absorption of photons. The self-focusing is also very strong with even tiny pulse energy far below damage threshold. Bulk fabrications of silicon by fs laser is not possible until recently by our group [Nat. Commun. 2016]. Single pulse modifications are also demonstrated only recently [Nat. Photon. 2017]. My topic is to develop practical techniques for bulk modifications with normal focusing approach. 3D internal inscriptions may open new possibilities for functional structures similar to those in dielectric materials that are already very successful.

Direction 2: Subwavelength laser fabrication

Thesis: Subwavelength laser fabrication using spatial/temporally shaped ultrafast laser pulses

  • Topic 1: “Stamping” sub-wavelength structures by spatially structured light

Taking the benefit of the tiny thermal effect of a ultrafast laser, the volume of melted material can be much less than that of long pulses, thus offering a possibility of nanoscale structures generation. The nanoscale melted materials are controlled by spatially structured light to generate target structures, including nanowires (<100nm) [Adv. Mater., 2015, 1st author], nano patterns(<140nm) [Opt. Express, 2017, 1st author], nanogap(<50nm)[ ACS Appl. Nano Mater.,2019], etc.

  • Topic 2: New temporal beam shaping techniques and its application in subwavelength fabrication

We proposed a novel design of pulse-train-generator based on multi-reflection between thin films. [Opt. Lsr. Tech.,2017, 1st author ] Temporally shaped beams can control the transient dynamics of laser-material interactions to obtain distinct results than unshaped ones. Applications including: nanoscale quantum-dots[Sci. Rep., 2017], nanoscale silica craters, higher etching efficiency[Appl. Surf. Sci. 2019 ].

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  • Topic 3: Subwavelength structures for ultra-trace molecules detection

Nanoscale structures can be used for many novel applications. One application aspect is to use the nanoscale structures for Surface Enhanced Raman Spectroscopy[ACS Appl. Mater. Interfaces, 2018]. Additional assisting method like hydrophobic-surfaces-condensing can be used to further increase the sensitivity as high as pico-molar level [J. of Mater. Chem. B,2016, 1st author].