Single whispering-gallery mode lasing in polymer bottle microresonators via spatial pump engineering

摘要

By engineering the spatial profile of a pump beam, scientists in China have made a bottle-shaped microresonator lase in a single mode. Whispering-gallery-mode microresonators, which rely on light circulating in a closed path around a disk, sphere, toroid or bottle, are popular due to their small size and high quality factor. However, they tend to be multimodal when lasing due to the lack of a mode-selection element. Fuxing Gu at the University of Shanghai for Science and Technology and co-workers overcame this limitation by using a pump beam with a striped interference pattern to excite a single transverse mode of a small polymer bottle microresonator. The result was a miniature single-mode laser with a low lasing threshold and high suppression of unwanted side modes.