Integrated Micro-Optical Fluorescence Detection System for Microfluidic211 Electrochromatography

摘要

We describe the design and microfabrication of an extremely compact optical211u001esystem as a key element in an integrated capillary-channel electrochromatograph 211u001ewith laser induced fluorescence detection. The optical design uses substrate-mode 211u001epropagation within the fused silica substrate. The optical system includes a 211u001evertical cavity surface-emitting laser (VCSEL) array, two high performance 211u001emicrolenses and a commercial photodetector. The microlenses are multilevel 211u001ediffractive optics patterned by electron beam lithograph and etched by reactive 211u001eion etching in fused silica. Two generations of optical subsystems are described. 211u001eThe first generation design is integrated directly onto the capillary channel-211u001econtaining substrate with a 6 mm separation between the VCSEL and the source to 211u001edetector length is further compressed to 3.5 mm. The systems are designed for 211u001eindirect fluorescence detection using infrared dyes. The first generation design 211u001ehas been tested with a 750 nm VCSEL exciting a 10 M solution of CY-7 dye. The 211u001eobserved signal-to-noise ratio of better than 100:1 demonstrates that the 211u001ebackground signal from scattered pump light is low despite the compact size of 211u001ethe optical system and meets the system sensitivity requirements.