Single bead near-infrared random laser based on silica-gel infiltrated with Rhodamine 640

Abstract

Photoluminescence properties of single bead silica-gel (SG) embedded with a laser-dye were studied aiming at the operation of near-infrared (NIR) Random Lasers (RLs). The operation of RLs in the NIR spectral region is especially important for biological applications since the optical radiation has deep tissue penetration with negligible damage. Since laser-dyes operating in the NIR have poor stability and are poor emitters, ethanol solutions of Rhodamine 640 (Rh640) infiltrated in SG beads were used. The Rh640 concentrations in ethanol varied from 10 À5 to 10 À2 M and the excitation at 532 nm was made by using a 7 ns pulsed laser. The proof-of-principle RL scheme herein presented was adopted in order to protect the dye-molecules from the environment and to favor formation of aggregates. The RL emission from %650 nm to 720 nm, beyond the typical Rh640 monomer and dimer wavelengths emissions range, was attributed to the trade-off between reabsorption and reemission processes along the light pathways inside the SG bead and the contribution of Rh640 aggregates.

Fabrication of a dye-based random laser using ZnS:Mn quantum dots and investigating the effects of their concentration

“…6 (c) is the red-shift of the gain lineshape in the presence of the scatterer nanoparticles compared to the photoluminescence spectrum I0(λ). This phenomenon can be explained based on the reabsorption and reemission of light by the dye molecules [51]. The spectral overlap of RhB absorption and emission spectra emitted intensity (a.u.)…”

Bi-chromaticity and tunability of random lasing in mesoporous silica SBA16 doped with rhodamine B

“…By controlling the excitation fluence, it is possible to vary the random laser emission wavelength from 590 nm of 610 nm. Another tuneable random laser system was developed exploiting the presence of nanopores and the random structure of silica gel beads infiltrated with rhodamine 640 [27]. In this work, the authors demonstrated tunable RL emission in a range from 670 nm to 720 nm, which was attributed to reabsorption/reemission processes involving the dye molecules and their aggregates.…”

Engineering of Solid-State Random Lasing in Nanoporous Anodic Alumina Photonic Crystals

“…Of all materials, porous structures are particularly suitable platforms to design optically and electrically pumped RLs because light emission in these systems can be tailored by engineering the features of scattering centers (pores) through a variety of fabrication methods such as dry and wet chemical etching, template synthesis, and imprinting . Porous RLs can also be directly fabricated in materials with intrinsic light-emitting properties (e.g., semiconductors) or through functionalization of optically inert porous matrixes with light-emitting materials (e.g., fluorophores, semiconductor coatings, and quantum dots). , Recent advances in random-lasing technology have resulted in distinct forms of porous RLs such as etched semiconductors, organic fibers, nanowires, and porous ceramics . Nanoporous anodic alumina (NAA) produced by electrochemical oxidation (anodization) of aluminum substrates is a thin film of anodic aluminum oxide (alumina, Al 2 O 3 ) featuring hexagonally arranged, straight, cylindrical nanopores homogeneously distributed across its surface and along its thickness, from top to bottom. , This characteristic structure makes NAA an ideal platform material to develop lasing systems based on distinct forms of light–matter interactions.…”

“…21,26 Recent advances in random-lasing technology have resulted in distinct forms of porous RLs such as etched semiconductors, 27 organic fibers, 28 nanowires, 29 and porous ceramics. 30 Nanoporous anodic alumina (NAA) produced by electrochemical oxidation (anodization) of aluminum substrates is a thin film of anodic aluminum oxide (alumina, Al 2 O 3 ) featuring hexagonally arranged, straight, cylindrical nanopores homogeneously distributed across its surface and along its thickness, from top to bottom. 31,32 This characteristic structure makes NAA an ideal platform material to develop lasing systems based on distinct forms of light− matter interactions.…”