Mid-infrared imaging through up-conversion luminescence in trivalent lanthanide ion-doped self-organizing optical fiber array crystal.

We propose a scheme for imaging mid-infrared (MIR) wavelengths via pre-excitation-assisted up-conversion luminescence in lanthanide ion ()-doped Self-organizing Optical FIber Array (SOFIA) crystal. First, near-infrared pre-excitation wavelength excites an electron from the ground state to an excited state of . Next, the MIR wavelength to be imaged promotes this excited electron to a higher-lying energy state. Finally, relaxation of the electron from the higher-lying energy state to the ground state emits the up-conversion luminescence in the visible region, completing the MIR-to-visible wavelength conversion. An analysis of the 4 to 4 intra-configurational energy level transitions in , together with an appropriate selection of the pre-excitation wavelength and the visible luminescence constrained within the 500-700 nm wavelength range, reveals that trivalent erbium (), thulium (), holmium (), and neodymium () can be used to image MIR wavelengths. Our proposed scheme, called MIR imAging through up-Conversion LuminEscence in a SOFIA crystal, will enable the imaging of MIR wavelengths using low-cost optics and readily available silicon-based detectors in the visible spectral region and will open up new possibilities for MIR wavelength detection and imaging.