Abstract： The homogeneous, intensity modulated salinity sensor using the photonic crystal ring resonator （PCRR） is proposed and designed for monitoring the salinity of the seawater from 0% to 100% （0 g/L to 100 g/...Abstract： The homogeneous, intensity modulated salinity sensor using the photonic crystal ring resonator （PCRR） is proposed and designed for monitoring the salinity of the seawater from 0% to 100% （0 g/L to 100 g/L） at 25℃. The concentration of the salinity in the seawater changes the refractive index of the seawater. The change in the refractive index of the seawater brings the change in the output signal intensity of the sensor as the output power and mapping the salinity level, the seawater flows inside the sensor. By detecting the salinity can be evaluated. The proposed sensor is composed of periodic Si rods embedded in an air host with a circular PCRR placed between the inline quasi waveguides. Approximately, 2.69% of output power reduction is observed for every 5% （5 g/L） increase in the salinity as the seawater has a unique refractive index for each salt level. With this underlying principle, the performance of the sensor is analyzed for different temperatures.展开更多
文摘氮化铝(AlN)作为一种宽带隙半导体,具有优异的物理和化学性能,在紫外发光二极管(Light Emitting Diode,LED)领域有着广泛的应用。同样,发展较为成熟的氮化镓(GaN)在该领域也有着不可替代的作用。而高性能的器件需要有良好的外延层。AlGaN基紫外LED外延层的传统制备方法是采用金属有机化学气相沉积法(Metal Organic Chemical Vapor Deposition,MOCVD),但是由于该方法中存在着强烈的预反应和Al原子本身迁移速率慢等原因,导致外延层中出现大量缺陷,使得紫外LED器件的性能降低。此外,由于不同材料以及材料与空气的折射率存在差异,使得光难以逃逸到外界,大部分光被局域在芯片内部,从而降低光提取效率以及光强。为了提高器件的光学性能,一种新的紫外LED结构被提出,文章采用时域有限差分模拟(Finite Difference Time Domain,FDTD)软件对该外延结构的光提取效率和出光强度进行了仿真。研究发现,与传统的LED结构相比,新型紫外LED结构的横磁波(TM)光模式和横电波(TE)光模式的光提取效率分别提高了19.1%和29.3%,最大出光强度分别提高了42.78%和47.18%,对器件的光学性能有着显著的改善。另外,文章还研究了新型紫外LED外延层的结构参数对器件整体光学性能的影响,在光源、物理模型尺寸和仿真条件等因素不变的情况下,获得了光学性能最佳的结构参数。
文摘Abstract： The homogeneous, intensity modulated salinity sensor using the photonic crystal ring resonator （PCRR） is proposed and designed for monitoring the salinity of the seawater from 0% to 100% （0 g/L to 100 g/L） at 25℃. The concentration of the salinity in the seawater changes the refractive index of the seawater. The change in the refractive index of the seawater brings the change in the output signal intensity of the sensor as the output power and mapping the salinity level, the seawater flows inside the sensor. By detecting the salinity can be evaluated. The proposed sensor is composed of periodic Si rods embedded in an air host with a circular PCRR placed between the inline quasi waveguides. Approximately, 2.69% of output power reduction is observed for every 5% （5 g/L） increase in the salinity as the seawater has a unique refractive index for each salt level. With this underlying principle, the performance of the sensor is analyzed for different temperatures.
