基于亚波长光栅结构的微流控可调窄带滤波器设计与分析

Tunable Narrow-Band Filter with Sub-Wavelength Grating Structure by Micro-Optofluidic Technique

可调窄带滤波器是光学系统中的核心器件之一,在光信号处理、光学传感等领域中有广泛的应用价值。基于亚波长光栅结构,利用微流控技术,提出了一种新型可调控窄带滤波器的实现方法,通过调控微流体通道中流体的折射率,获得了大范围可调窄带滤波功能。采用严格模式理论对其光学性能进行了分析与模拟,数值结果表明,该器件波长调谐范围可达28nm,其滤波带宽不大于0.03nm,灵敏度S大于350nm·RIU^(-1),品质因数Q高达50000,光学性能优异。另外,该新型器件具有结构简单、易于制作、调控简便等诸多优点,在生物传感、化学分析等领域具有广阔的应用前景。

The tunable optical narrow-band filter is one of the key components in an optical system,which has a wide application in many fields such as optical signal processing and optical sensing.A novel scheme for a widely tunable narrow-band filter is proposed using the micro-optofluidic technology and based on a sub-wavelength grating structure,in which a wide-range adjustable narrow-band filtering function is achieved by adjusting the refractive index of mixed liquid in the micro-fluidic channel.The optical performance is numerically investigated using the rigorous mode theory and the simulation results show that the tunable wavelength range of the designed device is over 28 nm,the filtering bandwidth is less than 0.03 nm,the sensitivity Sis over 350 nm·RIU-1,and the quality factor Qis over 50000,indicating that the performance is superior.Moreover,the proposed novel device has many advantages such as simple structure,ease for fabrication and large fabrication tolerance,which is very useful in the fields of bio-sensing,chemical analysis and others.