基于2S2G棱镜的新型反向表面等离子共振生物传感器

Brand-New Ge_(20)Ga_5Sb_(10)S_(65) Prism Biosensor Based on Inverted SPR

提出了一种基于反向表面等离子体共振原理,由Ge_（20）Ga_5Sb_（10）S_（65）-钯-石墨烯分子-生物分子四层结构构成的新型生物传感器。当生物分子之间发生相互作用时,引起生物分子层折射率的变化,从而导致反向表面等离子体共振角的偏移。在此基础上,根据传输矩阵法推导了传感器的输出光谱,重点讨论了本文提出的传感器与传统传感器相比,在灵敏度、分辨率、动态检测范围以及检测信号信噪比方面取得的进展。另外,通过对比研究,深入分析了辅助介质层石墨烯厚度对传感器性能的影响。最后,利用近红外光作为提出的传感器的入射光,分析了在近红外区域传感器性能的改善。研究结果表明：单层石墨烯分子使传感器性能达到最佳;反向表面等离子共振峰强度约为入射光强的80%~90%,使传感器的输出信号具有较大的信噪比;在可见光区域,当入射光波长为632.8nm时,提出的反向表面等离子共振生物传感器的分辨率是基于SiO_2棱镜耦合反向表面等离子共振生物传感器的1.9倍,是传统表面等离子共振生物传感器的3.5倍,提出的传感器的动态检测范围约是现有传感器的2倍;利用Ge_（20）Ga_5Sb_（10）S_（65）棱镜可使反向表面等离子共振生物传感器检测光波长由可见光区域扩展到近红外区域,当入射光为1 000nm时,传感器的分辨率是可见光区域的3~4倍。该研究对基于反向表面等离子体共振原理生物传感器的实现与发展具有重要意义。

Based on inverted surface plasmon resonance（ISPR）a novel biosensor consisting of Ge_（20）Ga_5Sb_（10）S_（65）-palladium-graphene layer-biomolecule layer is proposed.The refractive index of biomolecule layer alters as biomolecule experience interactions,thus leading to a shift of ISPR angle.On this basis,the spectrum output of sensor is derived by transfer matrix method.The sensitivity,the resolution,the dynamic detection range and the signal to noise ratio of the presented sensor are discussed and compared with the performance of traditional sensors.Moreover,the influences of grapheme layer thickness on sensors are analyzed with comparative study.Finally,near infrared is used as the incident light of the presented sensor.The results show that,the best thickness of grapheme layer is monolayer;the peak intensity of the ISPR reflection is about 80%~90% of intensity of incident light,guaranteeing a high signal to noise ratio;In the visible light,whenλ=632.8nm,the presented sensor is 1.9times the resolution of the sensor based on SiO_2 coupling inverted surface plasmon resonance,is 3.5times the resolution of the sensor based on surface plasmon resonance（SPR）,and is 2times the dynamic detection range of pre-existing biosensor based on SPR.The application of Ge_（20）Ga_5Sb_（10）S_（65） prism extends the detection light wavelength from the visible region to the near infrared region.Whenλ=1 000 nm,the sensor is 3~4times of the sensor in visible region.The research greatly contributes to the realization and application of biosensor based on inverted surface plasmon resonance.