High Energy Lab (Lab2 - A642)

In this laboratory, we have our highest energy femtosecond pulses of 5 mJ with a 1 kHz repetition rate from a Ti:Sapphire regenerative amplifier system. We utilize these powerful laser pulses to study nonlinear processes and to do pump-probe spectroscopy in different domains of the electromagnetic spectrum. By supercontinuum generation, we cover the visible to NIR spectrum ranging from 240 nm to 20 µm; by photoconductive antenna/waveguides, we generate THz radiation covering the millimeter region. With different experimental setups, including two-color pump-probe, transient absorption spectroscopy, and time-resolved optical pump terahertz probe time-domain spectroscopy, we studied charge and carrier dynamics in organic photovoltaic and 2D van der Waals materials [1-4]. Besides fundamental research, we also engage in the development of new technologies, for example, we work on development of THz radiation sources [5,6], and in biomedicine applications including wide-field temporal focused two-photon microscopy [7] and photo-stimulated drug delivery system [8].

• [1] M. B. M. Krishna et al., Semicond. Sci. Tech. 33, 084001 (2018)
• [2] V. Pareek, J. Madéo, and K. M. Dani, Phys. Rev. Lett. 124, 057403 (2020)
• [3] C. E. Petoukhoff et al., Mol. Syst. Des. Eng. 4, 929 (2019)
• [4] A. Karmakar et al., ACS Nano 16, 3, 3861–3869 (2022)
• [5] F. Miyamaru et al., Phys. Rev. Lett. 127 (5), 053902 (2021)
• [6] V. K. Mag-usara et al., iScience 25, 7, 104615 (2022)
• [7] V. Lisicovas et al, Methods Protoc. 2, 65 (2019)
• [8] T. Nakano et al., Pharmaceutics 14, 468 (2022)

MAJOR EQUIPMENT

• Spectra Physics Spitfire Ace (800 nm, 1 kHz, 5 mJ, 70 fs)
• Spectra Physics MaiTai (800 nm, 42 MHz, 19 nJ, 40 fs)
• Newport Transient Absorption Spectrometer
• Toptica FemtoFiber Pro NIR (780 nm @140 mW or 1560 nm @350 mW, 80 MHz, < 100 fs)

EXPERIMENTAL SETUPS

• Transient absorption spectroscopy
• Two color pump probe
• THz time-domain spectroscopy and optical pump - THz probe
• Laser ablation process
• Wide field two-photon microscope
• Micro pump probe