Room-temperature continuous-wave indirect-bandgap transition lasing in an ultra-thin WS2 disk

Junghyun Sung, Dongjin Shin, Hyun Hee Cho, Seong Won Lee, Seungmin Park, Young Duck Kim, Jong Sung Moon, Je Hyung Kim, Su Hyun Gong

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Small semiconductor lasers that can be integrated on a chip are essential for a wide range of optical applications, including optical computing, communication and sensing. Practical laser applications have only been developed with direct-bandgap materials because of a general belief that lasing action from indirect-bandgap materials is almost impossible. Here we report unexpected indirect-bandgap transition lasing in an ultra-thin WS2 disk. We demonstrate that a 50-nm-thick WS2 disk offers efficient optical gain and whispering gallery modes that are sufficient for lasing action. As a result, the WS2 disk exhibits indirect transition lasing, even under continuous-wave excitation at room temperature. Our experimental results are in close agreement with theoretical modelling for phonon-assisted photon lasing. The results derived from external cavity-free ultra-thin WS2 layers offer a new direction for van-der-Waals-material-based nanophotonics and introduce the possibility for optical devices based on indirect-bandgap materials.

Original languageEnglish
Pages (from-to)792-797
Number of pages6
JournalNature Photonics
Issue number11
Publication statusPublished - 2022 Nov

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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