Direct laser-writing of glass-based planar waveguide for fluorescence imaging

Abstract

Fluorescent microscopic imaging technology has the characteristics of strong labeling ability, high signal strength, low experimental cost, simple imaging process and imaging from living to in vitro, which is widely used in biological analysis imaging research such as tumor cell imaging, drug distribution in vivo detection, but how to simultaneously have a wide field of view and high resolution is a major difficulty in the current field of fluorescence microscopic imaging. Planar silicon waveguides have been found to be able to achieve a wide range of imaging of ultra-thin samples. However, they require sputtering deposition or ion beam etching and other preparation processes. The related processes are complex and equipment is expensive. In this paper, a planar waveguide type fluorescence microscope device based on picosecond laser direct writing is designed, which uses picosecond laser to etch the glass surface to rapidly prepare micron sized grooves, and further realizes low-cost and batch preparation of glass based planar waveguides by spinning SU-8 photoresist. The waveguide diameter and depth can be customized by adjusting laser processing power, frequency, scanning speed and other parameters. The microscopic detection experiment using Rhodamine B fluorescent molecule verified that the laser direct writing glass based planar waveguide fully meets the needs of biological imaging with high resolution and large field of view. This simple and rapid processing method can effectively improve the economic and social benefits in the field of fluorescence imaging.