Novel Fiber Optofluidic Laser And Its Application In High Performance Biochemical Sensing

Optofluidic laser integrates optics and microfluidic,which is an emerging technology widely explored in investigating light-matter interaction.By taking the advantage of microcavity and liquid gain medium,optofluidic laser can be used as on-chip source and biosensor.However,the optofluidic laser cannot meet the requirements of biosensing in three aspects:(1)Disposable use.It's hard to realize mass production of microcavity with identical optical properties,limiting the realizing of optofluidic laser with high reproducibility.(2)High throughput sensing.The low reproducibility of microcavity also restricts the realization of high-throughput sensing based on optofluidic laser.(3)Ultra-high sensitivity.The conventional optofluidic laser contains a massive number of gain molecules to achieve lasing threshold.The strong lasing emission become large background,making the weak sensing signal undistinguishable.This mechanism restricts the further improvement in the sensitivity of optofluidic laser.Overall,the high-performance biosensor with high throughput and high sensitivity becomes an imperative requirement.Here,we propose novel fiber optofluidic lasers.For the first time,by utilizing the uniformity of fiber,reproducible fiber optofluidic laser and array were achieved.We also proposed high-throughput sensing chip.For the first time,we proposed fiber optofluidic laser with monolayer gain medium and demonstrated its ultra-high sensitivity.The main results are as follows:(1)We proposed reproducible fiber optofluidic laser,demonstrated the disposability and investigated the multiplexing of fiber optofluidic laser.We theoretically investigated the optical feedback mechanism in twin hole fiber(THF).We also investigated the reproducibility(s=6.5%)of fiber optofluidic laser.In order to extend the function of fiber optofluidic laser in multi-sample and multi-parameter detection,we investigated the multiplexing of fiber optofluidic laser.By integrating different fiber optofluidic laser,we achieved laser array,which can be used in multi-sample detection.We also carried out pseudo whispering gallery mode fiber optofluidic laser,which enables high density integration of multi-channels in a single fiber.(2)We demonstrated the first distributed fiber optofluidic laser and proposed the high-throughput sensing chip.By taking the advantage of uniformity(s(27)0.4%)in optical fiber,we demosntred the distributed fiber optofluidic laser.The emission spectrum,lasing threshold and spatial distribution was characterized by imaging.The laser emission result a low lasing threshold of 0.5mJ/mm~2 and a spatial uniformity with6.6%.The arrayed sensing chip was achieved by integrating the distributed fiber optofluidic laser as on-chip source and capillaries as sensing array,enabling enzyme detection with a lower detection limit of 14 pM.We also proposed the 2D sensing chip.Wavelength tunability over 250 nm was demonstrated by utilizing the reconfiguration of microfluidics.The number of sensing element can be further extended to 2500 by utilizing wavelength division multiplexing technology.In order to further extend the sensing capacity,we realized single mode fiber optofluidic laser with a signal to noise ratio(SNR)of 21 dB and a lasing threshold of 13.2mJ/mm~2.Due to the narrow emission band,the single mode fiber optofluidic laser enables multiplexing with high density,which can be used for high throughput sensing.(3)Highly sensitive detection of ion and Parkinson's disease biomarker was realized.Enzyme catalyzed reaction was induced to demonstrate the high sensitivity of optofluidic laser.The result shows that optofluidic laser can detect enzyme with a lower detection limit of 10 nM,which is 2 orders of magnitude lower than the fluorescence method.Optofluidic laser with monolayer gain was also realized,which enables highly sensitive immunoassay.Theoretical mode of optofluidic laser based biosensing was build,through which we investigate the main parameters affecting the sensitivity,including number of gain molecules and effective gain molecule rate.We realized the fiber optofluidic laser by conjecting the gain molecules on the fiber surface.The number gain molecules are about 10~7,which is 5 orders of magnitude than the conventional optofluidic laser.Furthermore,we also investigated the lasing threshold,photo bleaching,lasing uniformity and statistic characteristics.Finally,the linear range of avidin and biomarker of Parkinson's disease was from 1 pM to 1000 pM and 0.14 pM to4.2 pM,respectively.This work provides a new root for early diagnostic of main diseases.