Oxidative Stress and Plasma Membrane Repair in Single Myoblasts After Femtosecond Laser Photoporation.

Cell membranes are susceptible to biophysical damages. These biophysical damages often present themselves in challenging oxidative environments, such as in chronic inflammation. Here we report the damage evolution after single myoblasts were individually subjected to femtosecond (fs) laser photoporation on their plasma membranes under normal and oxidative conditions.

Polarization-dependent plasmonic coupling in dual-layer metallic structures at terahertz frequencies.

Dual-layer metallic wire-hole structures were fabricated and their terahertz transmission properties were measured. They exhibit polarization-dependent transmittance with large extinction ratios. Simulation and experimental results on structures with different wire-to-hole orientations provide strong evidence that the resonance peaks are caused by plasmonic coupling between the two metallic layers.

Plasmonic waveguiding in a hexagonally ordered metal wire array.

We propose the inclusion of a structured pattern of nanoscale metal wires in a silica fiber to form a symmetric plasmonic waveguide. The surface plasmon polariton modes within the waveguide are studied by varying the wire diameter and spacing. Simulation results show that hybridization of the single-wire mode and the gap plasmon mode can yield a hybrid mode with optimum propagation lengths comparable to those reported for other structures but with better light confinement.

Identification of source of calcium in HeLa cells by femtosecond laser excitation.

Calcium is an important messenger in cells and whose store and diffusion dynamics at the subcellular level remain unclear. By inducing a controlled slow subcellular Ca2+ release through femtosecond laser irradiation in HeLa cells immersed in different media, cytoplasm is identified to be the major intracellular Ca2+ store, with the nucleus being the minor store and the extracellular Ca2+ also contributing to the total cellular Ca2+ level. Furthermore, Ca2+ released in either the cytoplasm or nucleus diffuses into the nucleus or cytoplasm, respectively, at different rates and influences the Ca2+ release in those regions.

Comparison of continuous-wave terahertz wave generation and bias-field-dependent saturation in GaAs:O and LT-GaAs antennas.

Terahertz wave (THz) photoconductive (PC) antennas were fabricated on oxygen-implanted GaAs (GaAs:O) and low-temperature-grown GaAs (LT-GaAs). The measured cw THz power at 0.358 THz from the GaAs:O antenna is about twice that from the LT-GaAs antenna under the same testing conditions, with the former showing no saturation up to a bias of 40 kV/cm, while the latter is already beginning to saturate at 20 kV/cm.

Targeted photoporation and transfection in human HepG2 cells by a fiber femtosecond laser at 1554 nm.

We report the transfection of human hepatocarcinoma (HepG2) cells by femtosecond (fs) laser pulses at 1554 nm. It was found that HepG2 cells could be perforated transiently to admit propidium iodide by that laser. This photoporation was safe, as the membrane resealed itself within a short time and no mitochondrial depolarization was detected.

Quantum cryptography with perfect multiphoton entanglement.

Multiphoton entanglement in the same polarization has been shown theoretically to be obtainable by type-I spontaneous parametric downconversion (SPDC), which can generate bright pulses more easily than type-II SPDC. A new quantum cryptographic protocol utilizing polarization pairs with the detected type-I entangled multiphotons is proposed as quantum key distribution. We calculate the information capacity versus photon number corresponding to polarization after considering the transmission loss inside the optical fiber, the detector efficiency, and intercept-resend attacks at the level of channel error.