My recent research has focused on making LIBS more practical, quantitative, and field-deployable by combining compact instrumentation, improved sampling, chemometrics, and complementary spectroscopic information. A recurring theme has been the use of low-power, low-resolution, and cost-effective LIBS systems for quantitative analysis and classification of foods, alloys, ceramics, minerals, and biological samples. Representative applications include edible salts, soybean paste, kimchi, coffee beans, red chili powder, nickel alloys, steel, doped ceria, bile juice, fingernails, rubies, and lithium-bearing minerals. More recent studies have emphasized data fusion between elemental fingerprints from LIBS and molecular fingerprints from IR or NIR spectroscopy, as well as machine-learning models such as k-NN, LDA, SVM, PLS-DA, and variable-selection strategies. Overall, this stage aims to develop robust spectroscopic analysis methods that can support food authentication, biomedical screening, industrial materials analysis, and battery-material characterization. 

From around 2012, my research direction shifted strongly toward laser-induced breakdown spectroscopy (LIBS) and laser-ablation-based analytical chemistry. Early studies addressed practical analytical problems such as heavy-metal detection in water, classification of edible sea salts, calcium analysis using filter-paper substrates, and sulfur analysis in salt products. A major theme during this period was the development of simple but effective sampling strategies for liquids and salts, including filter-paper preconcentration, laser-patterned silicon wafer substrates, and laser-ablation sampling methods. Multivariate classification approaches such as PCA, PLS-DA, and SIMCA were also introduced to interpret LIBS spectra for food and salt authentication. This period transformed laser spectroscopy from a fundamental tool into a practical analytical platform for real-world samples. 

The second stage of my research expanded from simple diatomic molecules to more chemically and biologically relevant molecular systems. I studied jet-cooled biomolecules and molecular clusters, including DNA bases, amino acids, aromatic biomolecules, and water-solvated species, to understand conformational structures, excited-state dynamics, microsolvation effects, and nonradiative relaxation pathways. In parallel, I participated in studies on nanomaterial–biomolecule interactions and surface-enhanced Raman scattering, linking molecular spectroscopy with emerging nanophotonic platforms. Toward the end of this period, my work also began to include laser-induced plasma and laser-ablation phenomena, which later became a major direction of my analytical spectroscopy research. 

My early research focused on high-resolution laser spectroscopy of isolated molecules in supersonic molecular beams. Using resonance-enhanced multiphoton ionization and rotationally resolved spectroscopy, I investigated alkali-metal diatomic molecules such as K₂, Rb₂, KRb, and RbCs, with particular attention to electric quadrupole transitions, spin-forbidden transitions, hyperfine structures, and strongly perturbed electronic states. These studies provided detailed spectroscopic constants, molecular potential information, and insight into the coupling between electronic, vibrational, rotational, and nuclear-spin degrees of freedom. This period established the foundation of my research career: using laser-based spectroscopy to extract chemically meaningful information from complex optical spectra.