Optofluidic Dye Laser And Its Sensing Applications

Optofluidic dye laser are microfabricated with the dye liquid, which as the gain medium, and use the microfluidic technology to inject dye liquid, combined with the microcavity to realize the micro liquid laser. It has the characteristics of microfluidic technology, which can control the light and fluid in the nano-micro scale, then realize the high integration optical microfluidic devices and systems. The integration of dye laser and microfluidic technology not only promotes the development and integrity in Lab-on-a-Chip system and Micro total anslysis system, but also can be used to control the laser's characteristics in a dynamic way, this is solid state optical component system can't do. With the rapid development of micromachining technology and microfluidic technology, to produce small bulk and low power consumption integrated light source is becoming possible. In biochemical sensing applications are also have unique advantages.This paper focuses on the research of the dye laser and its sensing characteristics,at the time realize the low cost optofluidics laser based on the high repetition rate nanosecond pulse laser, which is worked as pump. And achieved the high-accuracy ways in measurement of microflow's velocity and the solution's pH.(1) The optofluidics laser based on the high repetition rate nanosecond pulse laser.In experimenting we use Rhodamine R6G dye as gain medium, square quartz capillary as microfluidic channel. And the coated plane mirror as the F-P resonant cavity to provide optical feedback. The effect of the microfluidic velocity on the laser quenching is researched in this system, and based on it realized the flow velocity sensor. We present the flow velocity sensor which is measurement by monitoring the attenuation of the output laser with time. The measured range is 1-100 ?L/min, and the minimum detectable velocity variation is 10 ?L/min. This sensor has high sensitivity and low detection limit in low velocity.(2) Optofluidics laser pH sensor. When R6G solution is mixed with sodium hydroxide solution at some extent rationin, the pH value of the R6G solution changed,cause the ionization equilibrium of the dye solution to move, then lead the changing of the fluorescence spectrum's envelope and intensity. The decrease even completely quenched of fluorescence intensity was caused by the addition of OH- in the solution.The fluorescence intensity of R6G decreased with the increase of pH. Based on it we realized pH detection by effect of quenching which caused by sodium hydroxide solution on fluorescent light. In this experiment, the concentration of R6G ethanol solution is 1mM (mmol/L), achieve the pH detection range is 11-14, and it has higher sensitivity.