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**10** 

*1China 2USA* 

**Lithography** 

*2California Institutes of Technology* 

**Fabrication of Circular Grating Distributed** 

Within recent years the development of polymer dye lasers has progressed to higher levels of performance and functionality. The most attractive advantages of polymer dye lasers include low-cost processing, wide choice of emission wavelengths, and easy fabrication on flexible substrates. Several waveguide dye lasers have been studied with emission wavelengths ranging from ultraviolet to near infrared (Y. Oki et al., 2002). By simply changing the fluorophore doped in the polymer, these lasers can be used as the tunable sources for various applications, such as spectroscopy (Y. Oki et al., 2002) and fluorescence excitation source (C. Vannahme, 2011). Furthermore, microlaser array with multiwavelength emissions can be achieved (Y. Huang et al., 2010) for more applications such as compact

Currently the integration of miniaturized active light sources such as lasers into microfluidic systems becomes an attractive approach for biological and chemical processes (D. Psaltis et al., 2006). A majority of microfluidic systems are based on external light sources. However, the coupling of optical signals in and out of the devices, typically by optical fibers, remains one of the major challenges in integrated optics. By making on-chip light sources, we can eliminate the optics alignment, which greatly reduces the complexity of the system (E. Verpoorte, 2003). For applications in biochemical analysis in microfluidic systems, a surface emitting laser would appear to be more useful than other lasers because of its stacked substrate structure. Therefore, we choose a circular grating structure as the laser resonator design to produce low-threshold surface emitting lasing. The laser operating characteristics can be significantly improved by the two-dimensional nature of the resonator structure, and they are suitable to serve as low-threshold, surface-emitting coherent light source in

The 1-D distributed feedback (DFB) structure is a widely employed resonator geometry, and has been previously demonstrated for polymer lasers (Y. Oki et al., 2002). However, operating characteristics can be significantly improved within 2-D structures. Here, we choose a circular grating distributed feedback structure to obtain low threshold operation, a well-defined output beam, and vertical emission perpendicular to the device plane.

**1. Introduction** 

microfluidic networks.

displays and multiwavelength biosensors.

**Feedback Dye Laser by Nanoimprint** 

Yan Chen1, Zhenyu Li1, Zhaoyu Zhang1 and Axel Scherer2 *1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences* 

