Usually, only focused femtosecond (fs) lasers at near-infrared (NIR) range can induce photo-damage to transparent cells, making it difficult to treat large amount of cells by such optical methods for photostimulation. In this study, we clarify the mechanism of photodamage to cells that are co-cultured with gold nanorods (GNRs) by fs laser. The pulse duration and repetition rate of the fs laser play a key role in cell damage suggesting that the heat accumulation con-tributes to the major part for the cell damage rather than the high peak power which mainly determines the efficiency of multiphoton excitation. We further show that cellular Ca2t can also be released in this scheme, but the process is more sensitive to peak power. Our results can provide a large-scale GNR-mediated photostimulation for cell signaling modulation.

We report the fabrication and optical characterization of spherical whispering gallery mode (WGM) resonators made from ultraviolet (UV)-curable adhesive. The fabricated microspheres have good sphericity and surface smoothness, and can directly adhere to the tip of half-tapered fibers for easy manipulation. WGMs are efficiently excited in the microsphere using an evanescent field of the tapered silica optical fibers. Resonances with quality factors of 1.3 \times 105 are observed. The dependence of wavelength shifts of WGM resonances on the input light powers shows that the resonant wavelength of the proposed microsphere resonators can be tuned thermo-optically.

A novel hollow core photonic crystal fiber (HCPCF) temperature sensor that is based on intensity modulation and metal-organic-coordinated Co-cage supramolecular material filled in the air holes of the fiber is introduced. Temperature-dependent character of the structure in the range of 90 to 190 oC has been investigated. The numerical analyses show that the confinement loss is both decreased linearly with temperature at 1 064 and 1 550 nm. For a 6.5-cm long HCPCF, the sensitivity of temperature is experimentally determined to be 9.5 10?2 dB/oC at 1 064 nm, and 7.9 \times 10?2 dB/oC at 1 550 nm, respectively.

A polymer/silica hybrid 2 \times 2 multimode-interference Mach–Zehnder interferometer thermo-optic (TO) switch is designed and fabricated. Instead of polymer, silica is used as under-cladding to accelerate heat release because of its large thermal conductivity. The developed switch exhibits low power consumption of 6.2 mW, low crosstalk of about –28 dB, and short response time. The rise and fall times of 103 and 91 \mu s for this hybrid switch are shortened by 40.8% and 52.4%, respectively, compared with those of the fabricated TO switch (174 and 191 \mu s) using polymer as both upper- and under-claddings.

Electro-optic (EO) effect and thermo-optic (TO) effect are jointly considered on the basis of field-induced and temperature-affected perturbations of the operating point in waveguide components. TO coefficients of EO fluorinated polyimide films with side-chain azobenzene chromophore were measured by attenuated-total-reflection (ATR) technique at different temperatures with TE- and TM-polarized lights, respectively. It is found that the absolute values of TO coefficients increase with the increments of both chromophore concentration and film thickness, but the polarization dependence of TO coefficients increases with the increment of chromophore concentration and decreases with the increment of film thickness.

The main refractive indices of calcite crystal are measured by the means of auto-collimation, and the thermo-optical coefficients are calculated. The coefficient expression of Sellmeier equation is obtained by solving Sellmeier equation strictly and the refractive indices of different wavelengths are calculated, which accord with experimental results very well. The measured main refractive indices of calcite at 488-nm wavelength are identical with the values obtained by Sellmeier equation.

A novel nanopolycrystalline structure of vanadium dioxide thin films is deposited on silicon or fused silica substrates by reactive ion sputtering and followed by an annealing. The characteristic analysis shows that the films have a columnar nanostructure with an average grain of 8 nm. The resistivities as a function of ambient temperatures tested by four-point probes for as-deposited films present that the transition temperature for nanostructure of vanadium dioxide films is near 35 Celsius degree which lowers about 33 Celsius degree in comparison with the transition temperature at 68 Celsius degree in its microstructure.