【摘要】：由于體積小,可抗電磁干擾,高靈敏性與穩(wěn)定性等優(yōu)勢,光纖傳感器得到廣泛關(guān)注,應(yīng)用于臨床診斷、環(huán)境保護和食品安全等各個領(lǐng)域。本文設(shè)計并研制了一種基于薄芯光纖模式干涉的氨傳感器。將一段薄芯光纖嵌入標(biāo)準(zhǔn)單模光纖中,并在薄芯光纖表面利用層層(Lb L)自組裝技術(shù)進行敏感薄膜的涂覆。傳感過程基于敏感薄膜對氨的選擇性吸附,從而導(dǎo)致敏感薄膜折射率和輸出干涉光譜發(fā)生改變,通過對中心波長移動量的分析來對氨實現(xiàn)傳感檢測。本文主要研究工作如下:(1)利用Beam PROP軟件,對薄芯光纖傳感器進行模型的構(gòu)建。通過仿真獲得了不同長度的傳感器透射譜�？紤]成本以及便于操作等問題,后期的模擬以及實驗全部采取2cm薄芯光纖進行傳感器的構(gòu)建。模擬該傳感器的折射率靈敏性,再與實驗進行對比驗證。結(jié)果皆顯示隨著外界折射率的逐漸增大,透射譜的中心波長逐漸發(fā)生紅移,呈線性遞增。對薄芯光纖模式干涉儀型傳感器進行溫度靈敏性的測試,溫度靈敏性只有17.47pm/℃。結(jié)果說明該傳感器抗溫度干擾能力強,是理想的折射率傳感器。(2)采用層層靜電自組裝技術(shù)在基底上制備了(PAH/PAA)和[(PVPMC+PAH)/PAA]無孔薄膜。掃描電鏡結(jié)果顯示PAH/PAA雙分子層厚度為40nm,(PVPMC+PAH)/PAA雙分子層厚度為46nm。在氯化鈉溶液中對[(PVPMC+PAH)/PAA]薄膜進行處理,將PVPMC從三組分體系中去除,可形成大小為20-40nm的納米孔洞。(PAH:聚丙烯胺鹽酸;PAA:聚丙烯酸;PVPMC:羧酸類聚甜菜堿)(3)將(PAH/PAA)薄膜組裝至薄芯光纖的外表面,在不同濃度的氨溶液中進行傳感實驗。隨著濃度的逐漸增加,透射譜中心波長向短波長方向線性移動,移動量為6.87nm,傳感器的靈敏性為0.027nm/ppm。傳感器在選擇性實驗中表現(xiàn)出對氨良好的選擇性,并且恢復(fù)性良好,動力學(xué)響應(yīng)時間約為160s,恢復(fù)時間約為200s。利用折射率儀對不同氨濃度下(PAH/PAA)薄膜的折射率變化進行監(jiān)測,結(jié)果顯示隨氨濃度增加,折射率總共減小0.006625,理論折射率靈敏性為850nm/R.I.U.。將(PAH/PAA)多孔薄膜組裝至薄芯光纖的外表面,響應(yīng)時間由160s縮短至70s,恢復(fù)時間也由200s縮短至80s。(4)敏感薄膜(PAH/PAA)+[PAH/(PAA+SWCNTs-COOH)]組裝至薄芯光纖表面制作氨氣傳感器,在不同濃度的氨氣中進行傳感實驗。隨著氨氣濃度逐漸增加,透射譜的中心波長向短波長方向移動,在氨濃度1-20ppm之間,呈線性移動。氨氣濃度范圍1-20ppm時,傳感器的靈敏性為0.031nm/ppm。傳感器在選擇性實驗中表現(xiàn)出對氨良好的選擇性,并且恢復(fù)性良好,動力學(xué)響應(yīng)時間約為30s,恢復(fù)時間約為75s。(SWCNTs-COOH:羧酸修飾的單臂碳納米管)
[Abstract]:Due to its advantages of small size, resistance to electromagnetic interference, high sensitivity and stability, optical fiber sensors have been widely concerned and applied in many fields such as clinical diagnosis, environmental protection and food safety. In this paper, a kind of ammonia sensor based on thin core fiber optic mode interference is designed and developed. A section of thin core fiber is embedded in standard single mode fiber, and the sensitive film is coated on the surface of thin core fiber by layer-by-layer (Lb L) self-assembly technology. The sensing process is based on the selective adsorption of ammonia by the sensitive film, which results in the change of refractive index and output interference spectrum of the sensitive film. Through the analysis of the shift of the central wavelength, the sensing detection of ammonia is realized. The main research work in this paper is as follows: (1) the model of thin-core optical fiber sensor is constructed by using Beam PROP software. The transmission spectra of sensors with different lengths are obtained by simulation. Considering the cost and ease of operation, the 2cm thin-core optical fiber sensor is adopted in the later simulation and experiment. The refractive index sensitivity of the sensor is simulated and compared with the experiment. The results show that with the increase of external refractive index, the center wavelength of transmission spectrum is redshifted gradually, and it increases linearly. The temperature sensitivity of thin core fiber optic interferometer sensor is only 17.47pm/ 鈩，

本文編號：2456537