Direct Laser Micromachining of Bi‑2212 Single Crystals for Terahertz Josephson Plasma Emitters
Author: Tsujimoto, Manabu
Affiliation: National Institute of Advanced Industrial Science and Technology (AIST)
Type: Poster
Display Dates: 22.07.2026 - 23.07.2026
Board: WT-103
Terahertz Josephson plasma emitters (JPEs) based on layered high‑Tc cuprate superconductors provide a unique platform for compact, voltage‑tunable, chip‑scale terahertz sources. In this study, we develop a rapid and maskless patterning technique for Bi2Sr2CaCu2O8+δ (Bi‑2212) JPEs using direct ultraviolet laser micromachining. Unlike conventional photolithographic or ion‑beam fabrication processes, this approach enables direct patterning of Bi‑2212 single crystals without wet processing, significantly simplifying device fabrication. Stable continuous‑wave terahertz emission is observed from devices with various electrode materials, including Ag and Cu, and their emission characteristics are evaluated through electrical transport and spectroscopic measurements. Despite the formation of surface machining debris along laser‑processed regions, these measurements reveal that uniform stacks of intrinsic Josephson junctions are preserved inside the Bi‑2212 crystals, which is essential for spontaneous phase synchronization among the stacked junctions. Furthermore, analysis of the machining geometry shows that the trench width and depth are not limited by optical resolution but are governed by thermally dominated laser ablation influenced by the highly anisotropic thermal conductivity of Bi‑2212. These results establish direct laser micromachining as an effective and versatile fabrication strategy for terahertz JPEs and related high‑Tc superconducting electronic devices.