Study On The Microfluidic Fabrication And Lasing Characteristics Of Cholesteric Liquid Crystal Multiple Emulsion Core-Shell Microstructures

Dye doped cholesteric liquid crystal(DDCLC)laser can be used as a simple,small-sized,large-area,flexible tunable laser or circular polarization light source by taking the advantage of its strong light intensity,small cavity volume and no need for external reflectors.In recent years,it has rapidly become a popular research hotspot in the international laser field and is potential to be widely used in the industry,military,and civilian fields.However,most of the DDCLC lasers should be sandwiched by two glass substrates with pretreated homogeneous anchoring surfaces and provide emission along the supramolecular helical axis perpendicular to the substrates,which makes the laser bulky.This significant drawback might restrict their potentials for integrated photonics and lab-on-chip applications.Therefore,the study of a facile self-alignment technology without a liquid crystal cell to realize miniaturization in the field of integrated optics has become an important trend in the research field of liquid crystal lasers.With the rapid development of research on the microscopic scale in biology,chemistry,materials science,medicine,pharmacology and other disciplines,the need for sample manipulation,processing,detection and reaction at the micro/nano scale has promoted the emergence of microfluidic technology.Microfluidic technology has the characteristics and advantages of small size,low consumption,simple and rapid,which make it gradually become a research hotspot.Single or multiple emulsion microstructures with uniform size and controllable morphology can be fabricated using microfluidic technology.Microfluidics is an effective method for obtaining highly monodispersed emulsion with controllable size and structure.The emergence and development of this technology has further pushed toward the research on many complex multiple emulsion core-shell microstructures.In this study,the idea of DDCLC laser was combined with multiple emulsion core-shell microstructure.The fabrication of DDCLC water-in-oil-in-water(W/O/W)and oil-in-water-in-oil-in-water(O/W/O/W)type multiple emulsion microlasers were realized using coaxial glass capillary microfluidics.These microlasers were then pumped with different pumping beam diameters and their laser characteristics were tested by a self-built laser characterized system.The resonance mechanism of different lasing modes in the core-shell structure of multiple emulsions was studied and analyzed.Finally,the lasing modes in these microstructures were controlled by different methods.