Rare-earth photoluminescence in sol–gel derived confined glass structures

Photoluminescence from a Tb-doped photonic crystal microcavity for white light generation

“…For this purpose, a triple coupled microcavity with the structure (LH) 3 L 2 HLHL 2 HLHL 2 (HL) 3 was designed, where L and H represent low and high refractive index quarter-wave films. The reflection spectrum of this structure can be simulated by the transfer matrix method (TMM) [11,13]. Generally, this reflection profile contains three defect peaks (or "pass bands") located inside the stop band.…”

Rare-earth doped photonic crystal microcavities prepared by sol–gel

“…The preparation details, including the deposition on silica glass disks and the heat treatments performed, have been described in Ref. [4]. For the fabrication of the active layer, the SiO 2 sol was doped with Er (1 mol%) and/or Yb (2 mol%), in the form of nitrates.…”

“…Such a structure will exhibit a frequency region of high reflectivity, also called a 'stop band', where light undergoes Bragg reflection, with a maximum at the wavelength k. Moreover, when the structure has a defect, such as one missing layer (equivalent to a double thickness layer of the other material), this will cause the occurrence of an allowed state localized inside the stop band, or 'pass band', which will increase the functionality of the 1D PBG structure. This particular example is called a Fabry-Perot microcavity [2][3][4], while the presence of two defects creates a coupled microcavity. In a Fabry-Perot microcavity, the reflectance minimum, corresponding to the microcavity resonance (or pass band), appears at k = 2nx, where n and x are the refractive index and thickness of the defect layer.…”

“…Excitation can be provided with a diode laser at 980 nm, for example. However, the absorption cross-section of Er 3+ is small at this wavelength, so that Yb 3+ may be used as a co-dopant, to act as sensitizer [4,[6][7][8]. Therefore, besides Er 3+ -doped microcavities, Er 3+ /Yb 3+ co-doped structures have also been developed in this work, with the aims of increasing the Er 3+ PL efficiency and studying the energy transfer process in the microcavity structures.…”

Unconventional tailorable patterning by solvent-assisted surface-tension-driven lithography

“…Further to this, combining mechanically useful nanoparticles with the optical properties of rare earth ions, such as europium(III) ions, offers enormous technological potential in the area of photonic applications such as solid state lasers, sensors, optical amplifiers, scintillators, phosphors and optoelectronics displays and devices [5]. This could be particularly advantageous because Eu 3+ ions produce an intense red photoluminescence with narrow atomic emission profiles and provides an inexpensive, long lifetime and nontoxic method for fluorescence imaging compared to organic fluorophores [6][7][8].…”