Optofluidic Laser And Explosive Concentration Sensing Based On The Novel Organic Dyes

As combination of optical and microfluidic technology,the optofluidic laser integrates luminescent materials,optical resonators and microfluidic channels,and has significant advantages in biochemical sensing.When the donor-acceptor-donor organic dye is applied to the optofluidic laser,small changes in the molecular structure or concentration changes of the dye solution can be found by the micro-cavity amplification mechanism,which has obvious advantages compared with the conventional fluorescence sensing.The microfluidic laser is more sensitive than the fluorescence in detection,because of the specific structure of Fabry-Perot resonators in the optofluidic laser.Because the laser signal has a narrower line width and better directivity,the collected sensing signal light can filter out the interference of the fluorescent background,passing through the space filtering,spectral selection and other methods.Mostly,the intensity of the optofluidic laser is several orders of magnitude higher than the fluorescence intensity,enabling a larger detection range.In this paper,an optofluidic laser based on the donor-acceptor-donor organic dye was realized.On the one hand,the optofluidic laser retains the characteristics of high sensitivity,wide detection range,low detection limit,small sample dosage and low cost.On the other hand,fluorescent organic dyes have the advantages of fast response,low cost and easy synthesis,can be used to specific object to be detected and sensed.This paper focuses on the optofluidic dye laser and its sensing characteristics which is based on the donor-acceptor-donor organic dye.It mainly studies the microfluidic laser characteristics of the donor-acceptor-donor organic dye,and the optofluidic explosive sensing and its performance optimization based on the donor-acceptor-donor organic dye.The specific work is as follows:(1)This paper firstly introduces the design and construction of Fabry-Perot resonant cavity based on the optofluidic laser.The experiment used the square capillary with the outer diameter of 1.4 mm × 1.4 mm and the inner diameter of 1.1 mm × 1.1 mm.Two plastic hoses were connected to both ends of the square capillary.The gap was filled with UV glue.Then,it was solidified to form a microfluidic channel.Then,the microfluidic channel was putted in the two mirrors fixed by a bracket to form a Fabry-Perot cavity.(2)The optofluidic dye laser based on Fabry-Perot resonator is realized by using the alcohol solution of the donor-acceptor-donor organic dye as the gain medium.Under the 532 nm pulsed laser pumping,the best luminescent concentration of the donor-acceptor-donor organic dye solution was 0.5 mM.Next,the threshold,light stability and optical limiting effects of the donor-acceptor-donor organic dye were studied under the optimal luminescence concentration.Experiments show that the donor-acceptor-donor organic dye have significant advantages and lay the foundation for the following explosives sensing.(3)When the donor-acceptor-donor organic dye is mixed with DNT in a certain ratio,the quenching effect will occur,resulting in weakening of the fluorescence intensity.After the amplification of the F-P cavity,the corresponding laser intensity will be significantly reduced.Based on this characteristic,the detection of nitrobenzene explosives was designed to realize the sensing of DNT.The results show that the optofluidic laser based on the donor-acceptor-donor organic dye can achieve a large dynamic range of 4 orders of magnitude and a lower detection limit(10 nM).