| Summary: | 碩士 === 國立嘉義大學 === 光電暨固態電子研究所 === 98 === In recent years micro dye lasers have been investigated extensively. Many shapes of microresonators have been explored, such as disks, rings, spirals, polygons, asymmetric resonant cavities, stadiums, and others. The various shapes of the microresonator may affect the optical characteristics of the laser output. The fabrication quality of the device microstructure can also have the influence on the output light property. In this research we explore the technique of using the UV laser to fabricate the high-quality microstructured optoelectronic devices.
At first, we utilize the 355 nm UV laser to perform the photolithography directly on the dye-doped negative photoresist. Although we can fabricate the circular-grating microstructure by way of controlling the exposure power and exposure time, laser speckles with high coherence may induce high roughness in the devices. If we make use of a rotating diffuser to transform the laser light into a low coherence light source instead, the device roughness can be reduced substantially. Besides, we also utilize a lens to focus the laser beam at the rotating diffuser nearby. Adjusting the distance between the focal point and the diffuser can change the coherence level of the light. When the light coherence is lowered, the roughness of the fabricated device can be reduced, and the quality of the ring-shaped microstructure can also be improved.
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