基于聚合物材料的平面光波导生化传感器
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摘要
本论文针对基于有机聚合物材料的光波导生物化学传感器进行了基础性的研究工作。论文首先介绍了光波导传感器在光学传感中的重要地位,提出了有机聚合物材料运用于光波导生化传感器制备的独特优势,并简要介绍了光波导传感器的发展过程及现阶段国内外在此领域的研究进展;然后从导波光学的基础理论出发,阐述并推导了导模穿透深度,特征方程和截止条件等概念,以矩形波导为例分别介绍了马卡提里法和有效折射率法;之后对光波导传感器的传感机制—消逝场原理进行了阐释,在比较了其他几种波导传感器常用结构后,选择马赫-曾德尔(Mach-Zehnder,M-Z)干涉型结构作为传感器的波导结构,并介绍了传感器的工作原理:将传感波导的芯层裸露使其与待测液体充分接触,这样传输光的消逝场就能感知样品特性(如浓度、组分)变化实现折射率—相位—输出光功率的转化来达到生化传感的目的;由M-Z结构波导的传输矩阵,推导了波导传感器功率传递函数,以提高传感器灵敏度为主要目的,提出了传感器的设计要求;最后一部分中,介绍了聚合物波导制备工艺流程及各工艺参数。对紫外负性光刻胶SU-8材料的性质进行了深入研究,根据其在波导制备工艺中体现出的优势,提出并验证了SU-8材料可作为波导传感器芯/包层主体材料的可能性;为进一步调节芯/包层折射率,向SU-8中掺杂DR1(Disperse Red 1)材料,将掺杂后的DR1/SU-8材料作为波导芯层,SU-8材料作为波导上下包层制备M-Z结构波导,二次光刻后去掉了传感波导的上包层SU-8材料以形成传感窗口来完成波导传感器的制备。对器件进行了传感测试,向波导传感窗口区域滴加不同浓度的NaCl溶液可观察到输出功率变化。
As one of the priorities in scientific developments in 21st century, sensors have an irreplaceable status in obtaining and delivering information. They become the instrument of many professions such as automation, measurement, space technolog, military project and medical diagnostics etc. Developing novel, efficient, low-cost sensors is bound to promote scientific development. Integrated optical waveguide sensors not only possess the advantages of classic sensors, for instant, high sensitivity, rapid response, but also overcome the defects in miniaturization, intelligentization and integration. Combined with the outstanding superiority of organic polymers, utilizing the technology of integrated optical waveguide to the production of novel sensors, will undoubtedly be a highly potential research area.
This thesis is aimed at the basic research work of optical waveguide biochemical sensors with a Mach-Zehnder structure based on organic polymers. Main contents include the following aspects:
Part One: The significances of optical wavguide sensors are introduced, a unique advantage by applying organic polymer to the fabrication of optical waveguide bio-chemical sensors is brought forward and the development of optical waveguide bio-chemical sensors in China and other countries is briefly introduced;
Part Two: The concept of waveguide mode is expatiated based on the theory of optical waveguide. We also deduce penetration depth, eigenvalue equations of waveguide mode and the conditions for cut-off waveguide. On the basis of the slab waveguide theory, the condition for single mode transmission and cut-off conditions of channel waveguides are calculated by ways of Marcatili and effective refractive index respectively, which can be considered as the theoretical foundation for the analysis and design of the structure of optical waveguide sensors.
Part Three: Every main character of the waveguide sensor with an M-Z structure is analyzed in details in this part, which contributes a lot to the fabrication and test of sensor devices. The specific work can be separated into three sections below:
First of all, the principle of evanescent field, as the sensing principle of waveguide sensors is detailedly expatiated. The reason why most waveguide sensors work on the principle of evanescent field is that, the evanescent field is quite sensitive to the change of phase. Therefore, it is the most effective method to measure the refractive index of liquids by evanescent field. Besides, the detection based on evanescent field is real-time and non-invasion.
Compared with other common structures of waveguide sensors based on evanescent field, we choose the M-Z structure as our structure of devices. The M-Z structure not only performances well in sensitivity, but also is conveniently achieved by mature semiconductor process. Next, the working principle of waveguide sensor is introduced: one of the two waveguides is selected as a reference waveguide, and the other one is sensing waveguide. As the upper cladding layer of the sensing waveguide is removed, the core layer of waveguide is exposed. So a sensing window on the sensing waveguide is formed. By adding liquid sample with certain concentration, the evanescent field of the light in waveguide is altered according to the sample; at last, the changes in phase transform to the modification of the output power.
In the third section, the features of the waveguide sensor with an M-Z structure are specifically illustrated. The function of power transmission is deduced by transmission matrix and main factors which affect sensitivity are analyzed. Upon these, requirements for the design of the waveguide sensor with an M-Z structure are advanced:
(1)The conditiong for single mode transmission is calculated through the way of effective refractive index.
(2)The changes of phase must be confined at a monotone interval with a length ofπ, because the functions of power transmission and sensitivity are both periodic. Moreover, the sensor should work at aroundπ/2 + kπ, which is the linar area. By controlling the size of sensing window accurately, it can be achieved to promote the performance of sensors.
(3)By utilizing a reverse symmetry structure to enhance the evanescent field on sensing waveguide, we can obtain a previous improvement in the sensitivity.
Part Four: This is the key work in this thesis, several parts are included:
(1)According to the requirements of material used in planar waveguide devices, PMMA is selected as the waveguide material to study the basic fabrication procees such as spin-coating, evaporation, RIE and lithography. The structure of waveguide is observed by microscope and scanning electron microscopy. The familiarity with fabrication process lays an important foundation for the design and fabrication of waveguide sensor in the next step.
(2)The SU-8—negative,epoxy resin based UV photoresist is studied. As the refractive index of SU-8 can be modified easily, SU-8 resist is directly employed as the core/cladding materials herein. The capability of the straight waveguide with the structure of inverted ridge fabricated as the process of the SU-8 waveguide fabrication is tested. And we get good output near-field spots which verify the possibility that SU-8 fits for the main material of waveguides.
(3)In order to adjust the refractive indexes of core/cladding layer, DR1 is doped into SU-8 to form DR1/SU-8 which can be used as core layer with high refractive index according to the conditiong for single mode transmission of rectangle wavguides. After removing the flat layer of the core layer by RIE, better output near-field spots are obtained. After lithography, the sensing window is formed. The whole fabricationg of waveguide sensor is complete. We drip Nacl solution to the sensing window when the output is steady; we can observe a change in the output power with nearly 3.5dB, by using optical power meter.
As one of the priorities in scientific developments in 21st century, sensors have an irreplaceable status in obtaining and delivering information. They become the instrument of many professions such as automation, measurement, space technolog, military project and medical diagnostics etc. Developing novel, efficient, low-cost sensors is bound to promote scientific development. Integrated optical waveguide sensors not only possess the advantages of classic sensors, for instant, high sensitivity, rapid response, but also overcome the defects in miniaturization, intelligentization and integration. Combined with the outstanding superiority of organic polymers, utilizing the technology of integrated optical waveguide to the production of novel sensors, will undoubtedly be a highly potential research area.
This thesis is aimed at the basic research work of optical waveguide biochemical sensors with a Mach-Zehnder structure based on organic polymers. Main contents include the following aspects:
Part One: The significances of optical wavguide sensors are introduced, a unique advantage by applying organic polymer to the fabrication of optical waveguide bio-chemical sensors is brought forward and the development of optical waveguide bio-chemical sensors in China and other countries is briefly introduced;
Part Two: The concept of waveguide mode is expatiated based on the theory of optical waveguide. We also deduce penetration depth, eigenvalue equations of waveguide mode and the conditions for cut-off waveguide. On the basis of the slab waveguide theory, the condition for single mode transmission and cut-off conditions of channel waveguides are calculated by ways of Marcatili and effective refractive index respectively, which can be considered as the theoretical foundation for the analysis and design of the structure of optical waveguide sensors.
Part Three: Every main character of the waveguide sensor with an M-Z structure is analyzed in details in this part, which contributes a lot to the fabrication and test of sensor devices. The specific work can be separated into three sections below:
First of all, the principle of evanescent field, as the sensing principle of waveguide sensors is detailedly expatiated. The reason why most waveguide sensors work on the principle of evanescent field is that, the evanescent field is quite sensitive to the change of phase. Therefore, it is the most effective method to measure the refractive index of liquids by evanescent field. Besides, the detection based on evanescent field is real-time and non-invasion.
Compared with other common structures of waveguide sensors based on evanescent field, we choose the M-Z structure as our structure of devices. The M-Z structure not only performances well in sensitivity, but also is conveniently achieved by mature semiconductor process. Next, the working principle of waveguide sensor is introduced: one of the two waveguides is selected as a reference waveguide, and the other one is sensing waveguide. As the upper cladding layer of the sensing waveguide is removed, the core layer of waveguide is exposed. So a sensing window on the sensing waveguide is formed. By adding liquid sample with certain concentration, the evanescent field of the light in waveguide is altered according to the sample; at last, the changes in phase transform to the modification of the output power.
In the third section, the features of the waveguide sensor with an M-Z structure are specifically illustrated. The function of power transmission is deduced by transmission matrix and main factors which affect sensitivity are analyzed. Upon these, requirements for the design of the waveguide sensor with an M-Z structure are advanced:
(1)The conditiong for single mode transmission is calculated through the way of effective refractive index.
(2)The changes of phase must be confined at a monotone interval with a length ofπ, because the functions of power transmission and sensitivity are both periodic. Moreover, the sensor should work at aroundπ/2 + kπ, which is the linar area. By controlling the size of sensing window accurately, it can be achieved to promote the performance of sensors.
(3)By utilizing a reverse symmetry structure to enhance the evanescent field on sensing waveguide, we can obtain a previous improvement in the sensitivity.
Part Four: This is the key work in this thesis, several parts are included:
(1)According to the requirements of material used in planar waveguide devices, PMMA is selected as the waveguide material to study the basic fabrication procees such as spin-coating, evaporation, RIE and lithography. The structure of waveguide is observed by microscope and scanning electron microscopy. The familiarity with fabrication process lays an important foundation for the design and fabrication of waveguide sensor in the next step.
(2)The SU-8—negative,epoxy resin based UV photoresist is studied. As the refractive index of SU-8 can be modified easily, SU-8 resist is directly employed as the core/cladding materials herein. The capability of the straight waveguide with the structure of inverted ridge fabricated as the process of the SU-8 waveguide fabrication is tested. And we get good output near-field spots which verify the possibility that SU-8 fits for the main material of waveguides.
(3)In order to adjust the refractive indexes of core/cladding layer, DR1 is doped into SU-8 to form DR1/SU-8 which can be used as core layer with high refractive index according to the conditiong for single mode transmission of rectangle wavguides. After removing the flat layer of the core layer by RIE, better output near-field spots are obtained. After lithography, the sensing window is formed. The whole fabricationg of waveguide sensor is complete. We drip Nacl solution to the sensing window when the output is steady; we can observe a change in the output power with nearly 3.5dB, by using optical power meter.
引文
[1]徐静.基于聚合物集成光波导的MZI传感芯片的研究[D].浙江:浙江大学,2004.
[2]高福斌.硅基聚合物微光机械振动传感器的研究[D].吉林:吉林大学,2006.
[3]刘小为,高明,王东红,肖素艳.硅基光波导压力传感器[J].传感器技术, 2002,21(8):4-10.
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[6] L.BYOUNGHO.Review of the present status of optical fiber sensors [J].Optical Fiber Technology, 2003, 2:57-59.
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[10]李小甫,余海湖,江德生.光波导用SiO2/TiO2复合薄膜的制备及其性能研究[J].光电子技术与信息,2003,16(2):20-25.
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[12]初凤红,韩秀友,庞福飞,蔡海文,瞿荣辉,方祖杰.集成光波导传感器的研究进展[J].激光与光电子学进展, 2006, 3(42):21-25.
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[17]海日沙·阿不来提,麦麦提依明·马合木提,阿布力孜·伊米提高灵敏复合光波导传感器及其研究进展[J].化学传感器,2008,2(28):15-2.
[18]杜春雷,苗景奇.Ta2O5平面波导湿度传感器的研究[J].光学学报,1994,14(6): 662-667.
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[21]饶春芳,叶志清,胡友德.反对称模平面光波导生物传感器的研究与设计[J光电子激光,2007,5(18):578-561.
[22]范世福.光纤化学和生化传感技术[J].光谱仪器与分析,2002,3(73):58-60.
[23]李莹,钟金刚,张勇林,顾大勇,张亚鸥.表面等离子体共振成像生物芯检测系统[J].光子学报,2007,12(36):2290-2301.
[24]程根水,胡继文,张明秋.聚合物膜基信息传感材料[J].高分子材料科学与工程,2005,21(2):11-12.
[25] A.AIROUDJ, D.DEBAMO, E.GAVIOT. Integrated SU-8 photonic gas sensors based on PANI polymer devices: Comparison between metrological parameters [J].Optics Communication, 2009, 7:56-63.
[26] G.ANDRAUD, P.J.FRENCH, P.M.SARRO. Fabrication and characteristics of a PECVD SiC evanescent wave optical sensor [J].Sensors and Actuators A, 2008, 142:61–66.
[27] M.GERARD, A CHAUBEY, B.D. MALHOTRA. Application of conducting polymers to biosensors [J].Biosensors & Bioelectronics, 2002, 17:345-359.
[28] B.J.LUFF, J.S. WILKISON, J.PIEHLER, U.HOLLENBECH, J.INGENHOFF, Optical Mach–Zehnder Biosensor [J].Journal of Lightwave Technology, 1998, 4: 583-591.
[29] N.SKIVESEN, R.HORVATH, H.C.PPEDERSEN. Optimization of metal-cladwaveguide sensors [J].Sensors and Actuators B, 2005, 106:668–676.
[30] D.GUI, R. T. CHEN. Polymer-based highly multimode electro-optic waveguide modulator [J].Applied Physics Letters, 1998, 11(72):3139-3141.
[31] F.REHOUMA, D.PERSEGOL, A.KEVORKIAN. Optical waveguides for evanescent field sensing [J].Applied Physics Letters, 1994, 12(65):1477-1480.
[32] W.LUKOSZ. Integrated optical chemical and direct biochemical sensors [J]. Sensors and Actuators B, 1995, 10(29):37-50.
[33] Z.M.QI.A design for improving the sensitivity of a Mach-Zehnder interferometer to chemical and biological measurands [J]. Sensors and Actuators B, 2002, 9(81):254-258.
[34] F.PRIETO, A CALLE, A LLOBERA, A MONTOYA. An integrated optical interferometric nanodevice based on silicon technology for biosensor applications [J].Nanotechnology, 2003, 14:907-912.
[35] N.SKIVESEN, N.B.LARSEN. Reverse symmetry waveguide for optical biosensing [J].Chemical sensors and Biosensors, 2005, 9:279-301.
[36] B.Y. SHEWA, C.H. KUO, Y.C. HUANG, Y.H. TSAI. UV-LIGA interferometer biosensor based on the SU-8 optical waveguide [J].Sensors and Actuators A, 2005, 120:383–389.
[37]唐晓琪,唐继.Mach-Zehnder光纤干涉仪相位载波调制及解调方案的研究[J].计量学报,2002,1(23):11-15.
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[39]张峰,钟金刚.表面等离子体自适应测量光路[J].光电子激光,2006, 17(2):211-214.
[40] C.RAU, G.TOROSYAN, R.BEIGANG. Prism coupled terahertz waveguide sensor [J], Applied Phisics Letters, 2005, 86:5-6.
[2]高福斌.硅基聚合物微光机械振动传感器的研究[D].吉林:吉林大学,2006.
[3]刘小为,高明,王东红,肖素艳.硅基光波导压力传感器[J].传感器技术, 2002,21(8):4-10.
[4]孙振宏.用以健康监控的微型光学传感系统[J].生命科学仪器,2009,7(5):47-50.
[5]刘广玉.新型传感器技术及应用[M].北京:北京航空航天大学出版社,1995:203-205.
[6] L.BYOUNGHO.Review of the present status of optical fiber sensors [J].Optical Fiber Technology, 2003, 2:57-59.
[7] K.NAKAMURA, K.YOSHIDA.Special shape of fibers and sensor application [J].Optical Fiber Technology, 1997, 16:27-29.
[8] C.STAMM, W.LUKOSZ.Integrated optical difference interferometer as immunsensor [J]. Sensors and Actuators B, 1996(31):203-207.
[9]成娟娟,谢康.光波导生物化学传感器研究进展[J].激光与光电子学进展,2005 11(42):17-20.
[10]李小甫,余海湖,江德生.光波导用SiO2/TiO2复合薄膜的制备及其性能研究[J].光电子技术与信息,2003,16(2):20-25.
[11]王德强,陈玮,程继键.玻璃光波导研究进展[J].材料导报,2000,1(14):40-41.
[12]初凤红,韩秀友,庞福飞,蔡海文,瞿荣辉,方祖杰.集成光波导传感器的研究进展[J].激光与光电子学进展, 2006, 3(42):21-25.
[13]马少杰,李玉善.集成光波导电磁场传感器[J].光机电信息,2001,6(12):25-28.
[14]章燕申,胡朝阳,张斌,田芋,马新宇.集成光学角速度传感器及其关键器件的研制[J].中国惯性技术学报,2000,2(3):2-26.
[15]阿布力孜·伊米提,迪丽努尔·塔力甫,艾尔肯·吐尔逊.高灵敏复合光波导在检测臭氧的应用研究[J].分析化学,2005,11(33):1663-1665.
[16]徐国雄,黄振,倪旭翔.生物芯片检测系统中荧光信号强度[J].光子学报,2004 3(11):1192-1195.
[17]海日沙·阿不来提,麦麦提依明·马合木提,阿布力孜·伊米提高灵敏复合光波导传感器及其研究进展[J].化学传感器,2008,2(28):15-2.
[18]杜春雷,苗景奇.Ta2O5平面波导湿度传感器的研究[J].光学学报,1994,14(6): 662-667.
[19]李育洪,王克逸.基于平面光波导的光学传感器[J].安徽教育学院学报,2001,19(6):23-26.
[20]禹忠,汪敏强,姚熹.光通讯波段聚合物光波导材料的研究进展[J].化学通报,2001(l):5-10.
[21]饶春芳,叶志清,胡友德.反对称模平面光波导生物传感器的研究与设计[J光电子激光,2007,5(18):578-561.
[22]范世福.光纤化学和生化传感技术[J].光谱仪器与分析,2002,3(73):58-60.
[23]李莹,钟金刚,张勇林,顾大勇,张亚鸥.表面等离子体共振成像生物芯检测系统[J].光子学报,2007,12(36):2290-2301.
[24]程根水,胡继文,张明秋.聚合物膜基信息传感材料[J].高分子材料科学与工程,2005,21(2):11-12.
[25] A.AIROUDJ, D.DEBAMO, E.GAVIOT. Integrated SU-8 photonic gas sensors based on PANI polymer devices: Comparison between metrological parameters [J].Optics Communication, 2009, 7:56-63.
[26] G.ANDRAUD, P.J.FRENCH, P.M.SARRO. Fabrication and characteristics of a PECVD SiC evanescent wave optical sensor [J].Sensors and Actuators A, 2008, 142:61–66.
[27] M.GERARD, A CHAUBEY, B.D. MALHOTRA. Application of conducting polymers to biosensors [J].Biosensors & Bioelectronics, 2002, 17:345-359.
[28] B.J.LUFF, J.S. WILKISON, J.PIEHLER, U.HOLLENBECH, J.INGENHOFF, Optical Mach–Zehnder Biosensor [J].Journal of Lightwave Technology, 1998, 4: 583-591.
[29] N.SKIVESEN, R.HORVATH, H.C.PPEDERSEN. Optimization of metal-cladwaveguide sensors [J].Sensors and Actuators B, 2005, 106:668–676.
[30] D.GUI, R. T. CHEN. Polymer-based highly multimode electro-optic waveguide modulator [J].Applied Physics Letters, 1998, 11(72):3139-3141.
[31] F.REHOUMA, D.PERSEGOL, A.KEVORKIAN. Optical waveguides for evanescent field sensing [J].Applied Physics Letters, 1994, 12(65):1477-1480.
[32] W.LUKOSZ. Integrated optical chemical and direct biochemical sensors [J]. Sensors and Actuators B, 1995, 10(29):37-50.
[33] Z.M.QI.A design for improving the sensitivity of a Mach-Zehnder interferometer to chemical and biological measurands [J]. Sensors and Actuators B, 2002, 9(81):254-258.
[34] F.PRIETO, A CALLE, A LLOBERA, A MONTOYA. An integrated optical interferometric nanodevice based on silicon technology for biosensor applications [J].Nanotechnology, 2003, 14:907-912.
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