Yuan Xiaodong

Calculation of Guided Modes and Leaky Modes in Photonic Crystal Slabs

The scattering matrix S describing photonic crystal slabs is formulated. A new method is introduced to solve the eigenfrequency ω for a given Bloch wave vector K from the equation det S −1(ω,K) = 0. Using this method, we can obtain not only guided modes but also leaky modes in photonic crystal slabs with a higher-frequency resolution than that of the FDTD method.

Liquid Concentration Sensing Properties of Microfibers with a Nanoscale-Structured Film

A type of compact solution concentration sensor based on a microfiber with a nanoscale-structured film is proposed and demonstrated experimentally Additional loss at different solution concentrations is calculated by means of the three-dimensional finite-difference time-domain (3D-FDTD) method. The microfiber is fabricated by using the flame-heated scanning technique. Nanoscale-structured film is coated on the microfiber surface, which is assembled as a sensing unit. The sensitivity of this kind of sensor increases with the decreasing diameters of the microfiber. When the diameter of the microfiber is 2 ?m, a minimum concentration sensitivity of 1% (under 450 s measuring time) is demonstrated in the experiment. Higher sensitivity can be attained when the solution concentration is higher. The sensing properties of this microfiber with the nanoscale-structured film may provide opportunities for new applications in optical sensing devices.

Collective Thomson Scattering from Laser-Produced Plasmas

Time-resolved Thomson scattering was successfully performed to diagnose the parameters (ZTe, Ue and Ui) of laser-produced gold plasma. The results show that the collisionless dynamic form factor is accurate enough to be used for reducing the plasma parameters from the experimental data.

Observation of Thomson Scattering off Entropy Waves in a Laser-Produced Plasma

A new feature in the Thomson scattering spectrum is observed from a laser-produced aluminium plasma, which may be the Thomson scattering off entropy waves in the plasma. Such a feature is only observable when the energy of the heater beam is low enough.