Integration of blue–green electroluminescence structure in mid-infrared hollow optical fiber for targeting invisible CO₂ laser beam

Mid-infrared (IR) CO₂ lasers have important applications in laser medicine and material processing. However, the CO₂ laser beam is invisible to human eyes, it is not easy to accurately indicate the beam position in practical applications. In this work, we designed a PEDOT (Poly (3, 4-ethylenedioxythiophene))/ZnS: Cu/BaTiO₃/Ag electroluminescence (EL) structure and integrated it at the output end of the mid-IR hollow optical fiber. The blue–green light can be output along with the CO₂ laser beam in this EL structure integrated fiber, thus achieving the optical path indication and illumination of invisible laser beam. This work provides a possible guide for aiming the CO₂ laser beam in the min-IR optical fiber.