Sub-cycle Manipulation of Electrons in a Tunnel Junction with Phase-controlled Single-cycle THz Near-fields

By utilizing terahertz scanning tunneling microscopy (THz-STM) with a carrier envelope phase shifter for broadband THz pulses, we could successfully control the near-field-mediated electron dynamics in a tunnel junction with sub-cycle precision. Measurements of the phase-resolved sub-cycle electron tunneling dynamics revealed an unexpected large carrier-envelope phase shift between far-field and near-field single-cycle THz waveforms

Cell-Level Analysis Visualizing Photodynamic Therapy with Porphylipoprotein and Talaporphyrin Sodium

We revealed the difference in the mechanism of photodynamic therapy (PDT) between two photosensitizers: porphylipoprotein (PLP), which has recently attracted attention for its potential to be highly effective in treating cancer, and talaporphyrin sodium (NPe6). (1) NPe6 accumulates in lysosomes, whereas PLP is incorporated into phagosomes formed by PLP injection. (2) PDT causes NPe6 to generate reactive oxygen species, thereby producing actin filaments and stress fibers. In the case of PLP, however, reactive oxygen species generated by PDT remain in the phagosomes until the phagosomal membrane is destroyed, which delays the initiation of RhoA activation and RhoA*/ROCK generation. (4) After the disruption of the phagosomal membrane, however, the outflow of various reactive oxygen species accelerates the production of actin filaments and stress fibers, and blebbing occurs earlier than in the case of NPe6. (5) PLP increases the elastic modulus of cells without RhoA activity in the early stage. This is because phagosomes are involved in polymerizing actin filaments and pseudopodia formation. Considering the high selectivity and uptake of PLP into cancer cells, a larger effect with PDT can be expected by skillfully combining the newly discovered characteristics, such as the appearance of a strong effect at an early stage

Ultrafast carrier generation in Bi

Using terahertz-pump and terahertz-probe spectroscopy, we investigated terahertz-induced carrier generation processes in Bi1-xSbx thin films. The field dependence of the terahertz-induced transmittance change indicates distinct nonlinearity related to the Zener tunneling in narrow band-gap materials