Research On Sensor Arrays Characteristics Based On Radius-Graded Photonic Crystal Micro-Cavities

Photonic crystal (PhC) sensor is widely used for lab-on-a-chip applications due to its advantages including ultracompact size, high sensitivity and more suitable for monolithic integration. Photonic crystal cavity sensor has high quality factor (Q), high sensitivity and low detection limit. What’s more, photonic crystal sensor array using multiple cavities is essential for optical integrated circuit in the future. Radius-graded photonic crystal structure is suitable for sensor array. So, this paper has done research on radius-graded photonic crystal sensor array based on microcavities and the main work as follows:Firstly, based on the radius-graded along W1waveguide photonic crystal structure, we use six interlaced L3cavities to integrate a multifunctional and reconfigured photonic crystal biochemical sensor array. Every L3cavity is set in different areas with different radius. With adjusting the distance between cavities, we compress the size of sensor array. Then, we detect the sensor properties with different targets infiltrated into the air holes around the resonant cavities. The resonant wavelength will shift based on its refractive index change. While other resonant wavelength dips are unaffected. The sensitivity of this sensor array is nearly150nm/RIU.Secondly, radius-graded photonic crystal sensor array with interlaced and symmetrical cavities is proposed for biosensinig. Two L3cavities and two H1cavities are multiplexed and interlaced on both sides of a photonic crystal W1waveguide on the radius-graded photonic crystal slab. This design makes different cavities multiplexed on both sides of waveguide possible, which is better for compressing the array size. There exist four resonant wavelength dips in the transmission spectra. The quality factor is2000. In response to the refractive index change of air holes surrounding the cavities, four interlaced and symmetrical cavities are shown to independently shift their resonant wavelength without crosstalk. The simulation results demonstrate the refractive index sensitivity of sensor array varies from66.67nm/RIU to136.67nm/RIU corresponding to the number of functionalized air holes ranged from4to21. The detection limit is6.5×10-3.At last, we change the radius graded along the vertical direction of Wl waveguide. Interlaced cavities are multiplexed based on this structure. With changing the positions of air holes around resonant cavities, the quality factor is higher and the number of cavities is increased. The quality factor can be17000. Every cavity sensor can be independently sense without crosstalk. The photonic crystal sensor array can be used for multi biosensing detection and error-corrected detection. The cavity with high quality factor is promising for optical integrated circuit.All the above studies offer new ideas in PhC micro-cavity sensor array design and applications. It has important reference significance and application value for the ultra-large scale sensor array in the future.