Broad Visible Band Research Articles

Structural, optical, and shielding characteristics of CuO diborate glasses containing lithium fluoride or lithium oxide

A glass system of the basic composition xLiF-(25-x) Li2O-74.8B2O3 containing 0.2 CuO mol% dopant (x = 0, 5, 10, 15, 20, 25) was successfully prepared via the traditional melt quenching method. The sample was coded as 0LiF, 5LiF. 10LiF, 15LiF, 20LiF, 25LiF respectively. Combined optical, and Fourier transform infrared spectral measurements together with radiation shielding parameters were carried out. The amorphous nature of the present glasses was confirmed by utilizing X-ray diffraction patterns. UV/Visible electronic spectra of the studied sample disclose a strong UV absorption glass network. Copper-doped glasses display greenish-blue colors in combination with very broad visible bands pointing to a different overlapping peak. This extended characteristic band is related to absorption due to divalent copper (Cu2+) ions in distorted octahedral coordination. The FTIR data of the CuO-doped glasses reveal extended vibrational modes due to the presence of both triangular and tetrahedral borate glasses in their varying distinct wavenumbers. The Phys-PSD software has been used to compute shielding parameters including mass attenuation coefficient, tenth value layer, effective atomic number, mean free path, and build-up factors in the energy range of 0.015 to 15 MeV. Based on the obtained results, the investigated glasses have good features that make them very suitable for optical and shielding applications. Studied samples proposed to be used in optical devices as LiF appears to control optical parameters.

Convolution Operation on Pancharatnam-Berry Coding Metasurfaces in Visible Band

Coding metasurfaces bring photonic design into a new era for their convenience in manipulating electromagnetic waves in a programmable way. Different coding patterns can be further convoluted to give rise to nontrivial effects such as multiple beam steering, simultaneous control of surface and space waves, and the integration of multiple functionalities. However, previous experimental works have been limited to low frequencies. Extending convoluted coding metasurfaces to optical frequency can significantly reduce the size of structures, and therefore facilitate their applications in optical circuits. Here, we experimentally demonstrate a Pancharatnam-Berry metasurface designed by convoluting two distinct coding patterns. Such a metasurface exhibits integrated functionalities: the optical spin Hall effect and spin to orbital angular momentum conversion, which are robust over a broad visible band and a wide range of incident angles. Our work represents an important step towards multifunctional coding metasurfaces at optical frequency based on convolution operation.

The impact of electron beam irradiation on some novel borate glasses doped V2O5; Optical, physical and spectral investigation

New borate glass systems with composition of 56B2O3 + 25Li2O + 10Na2O + 5CaO + 2SrO + 2Al2O3 + 0.5 TeO2 + x V2O5, where × = 0.2 or 0.3 (wt. %), were fabricated via the traditional melting-annealing method at low temperature (650–750 °C). Some of the glasses optical, physical, chemical and spectral measurements were investigated within the impact of electron beam (EB) irradiation up to 8 kGy. UV–visible spectra revealed peaks at ∼ 290 and ∼ 300 nm for 0.2 and 0.3 V2O5 glasses, respectively. In addition to broad visible band at ∼ 580 nm owing to the participation of vanadium ions as V5+ with possible conversion to V3+/V4+ under the effect of EB irradiation. FTIR spectra revealed the main trigonal BO3 and tetrahedral BO4 units with an increase in N4 values by the progressive EB irradiation. ESR spectra revealed a gradual increase in intensity with irradiation doses. While, testing chemical durability in distilled H2O at 100 °C reveals a good manner before and after irradiation process. Some physical parameters e.g. optical energy gap (Eoptdirect and Eoptindirect), Urbach energy (EUrbach), refractive index (n) and spectral distribution (k) showed also a gradual decrease with continual irradiation owing to the gradual generating of non-bridging oxygens NBOs and progressive transformation of BO3 to BO4 units. The overall data displayed some dosimetric properties of the two studied glasses with a useful dose range 3–8 kGy of EB radiation. The study recommends usage of glasses as glass dosimeters in medical sterilization, industry and food irradiation processing.

Effect of temperature on optical, structural, morphological and antibacterial properties of biosynthesized ZnO nanoparticles

Nanomaterials can be produced by using nontoxic biological compounds that are both eco-friendly and economically viable. Temperature dependent ecological synthesis of ZnO nanoparticles was carried out with leaf extract of Ocimum sanctum. An electron microscope study confirmed that a temperature of 400 oC was optimal for the formation of ZnO nanoparticles generated by biosynthesizing ZnO nanoparticles. The normal crystalline size of biosynthesized ZnO nanoparticles calculated via XRD analysis are found to be 18, 12 and 17 nm for 300 - 500 oC, respectively. The direct optical band gap energy deducted from Tauc approximation range to be 3.32-3.20 eV. In SEM analysis, depending on the temperature of the synthesis conditions, different ZnO morphologies are also found. Functional groups analysis confirmed the incidence of carboxyl and amide groups in the O. sanctum leaf extract. The ZnO nanoparticles analysed at room temperature using photoluminescence, a broad visible band is observed around 382 nm for all samples. Furthermore, this study determines that the synthesized ZnO nanoparticles provide antimicrobial efficacy against clinical strains of Bacillus subtilis and Staphylococcus aureus, as well as against standard strains of Escherichia coli. Several fields, including cosmetics and pharmaceuticals, can benefit from biosynthesized nanoparticles.

A Machine Learning Algorithm for Himawari-8 Total Suspended Solids Retrievals in the Great Barrier Reef

Remote sensing of ocean colour has been fundamental to the synoptic-scale monitoring of marine water quality in the Great Barrier Reef (GBR). However, ocean colour sensors onboard low orbit satellites, such as the Sentinel-3 constellation, have insufficient revisit capability to fully resolve diurnal variability in highly dynamic coastal environments. To overcome this limitation, this work presents a physics-based coastal ocean colour algorithm for the Advanced Himawari Imager onboard the Himawari-8 geostationary satellite. Despite being designed for meteorological applications, Himawari-8 offers the opportunity to estimate ocean colour features every 10 min, in four broad visible and near-infrared spectral bands, and at 1 km2 spatial resolution. Coupled ocean–atmosphere radiative transfer simulations of the Himawari-8 bands were carried out for a realistic range of in-water and atmospheric optical properties of the GBR and for a wide range of solar and observation geometries. The simulated data were used to develop an inverse model based on artificial neural network techniques to estimate total suspended solids (TSS) concentrations directly from the Himawari-8 top-of-atmosphere spectral reflectance observations. The algorithm was validated with concurrent in situ data across the coastal GBR and its detection limits were assessed. TSS retrievals presented relative errors up to 75% and absolute errors of 2 mg L−1 within the validation range of 0.14 to 24 mg L−1, with a detection limit of 0.25 mg L−1. We discuss potential applications of Himawari-8 diurnal TSS products for improved monitoring and management of water quality in the GBR.

Optical, photoluminescence, and E.S.R spectral analysis of manganese ions in phosphate glasses melted under various conditions and impact of gamma irradiation

Glasses from NaCa fluorophosphate doped with varying MnO2 dopant (0.25, 0.50, 1.0%) and melted under different conditions were prepared by normal melting annealing technique. Collective optical, FTIR, photoluminescence, and E.S.R spectral measurements for the various MnO2-doped glasses were done. Optical spectrum of the undoped host fluorophosphate glass reveals only distinct UV absorption which is correlated to contaminated trace iron (Fe3+) ions present as impurities. The MnO2-doped glasses show the same UV absorption beside two additional bands, a small one at 410 nm which is assumed to originate from (Mn2+) ions of spin-forbidden nature and a broad visible and distinct band centered at 500 nm representing the absorption of trivalent manganese (Mn3+) ions of spin-allowed nature. The effects of varying melting conditions reveal obvious changes in the intensities of the two visible bands. FTIR spectra reveal extended vibrational peaks due to phosphate (PO4) groups with sharing of some fluorophosphate (PO3F) groups and the introduction of increasing percent of the dopant that causes minor variations in the FTIR spectra. Photoluminescence spectra reveal a broad emission band centered at about 635 nm and the intensity of the emission band increases with the increase of MnO2 content and is more distinct in glass melted under reducing conditions than that melted at normal condition. E.S.R spectral measurements were carried out to confirm the optical results indicating the existence of measurable divalent Mn2+ ions which increases in reducing conditions. The effects of gamma irradiation (6Mrad dose) on the studied spectral properties were evaluated.

Radio frequency plasma assisted surface modification of Fe3O4 nanoparticles using polyaniline/polypyrrole for bioimaging and magnetic hyperthermia applications

Surface modification of superparamagnetic Fe3O4 nanoparticles using polymers (polyaniline/polypyrrole) was done by radio frequency (r.f.) plasma polymerization technique and characterized by XRD, TEM, TG/DTA and VSM. Surface-passivated Fe3O4 nanoparticles with polymers were having spherical/rod-shaped structures with superparamagnetic properties. Broad visible photoluminescence emission bands were observed at 445 and 580 nm for polyaniline-coated Fe3O4 and at 488 nm for polypyrrole-coated Fe3O4. These samples exhibit good fluorescence emissions with L929 cellular assay and were non-toxic. Magnetic hyperthermia response of Fe3O4 and polymer (polyaniline/polypyrrole)-coated Fe3O4 was evaluated and all the samples exhibit hyperthermia activity in the range of 42–45 °C. Specific loss power (SLP) values of polyaniline and polypyrrole-coated Fe3O4 nanoparticles (5 and 10 mg/ml) exhibit a controlled heat generation with an increase in the magnetic field.

Iridium Complex of N-Fused Bilatrienone: Oxidative Cleavage of N-Fused Porphyrin Induced by Iridium-Cyclooctadiene Complexation.

N-fused porphyrin (NFP) is a unique class of photostable near-infrared dyes with an 18π aromatic tetrapyrrole macrocyclic skeleton containing a tri-fused pentacyclic moiety. Here, the synthesis of an iridium complex of N-fused bilatrienone is reported as the degradation product of Ir-cyclooctadiene (cod)-induced oxidative cleavage of NFP under aerobic conditions. Similar to the native bilin chromophores, the ring-opened complex featured a broken π-conjugation circuit and exhibited a broad visible absorption band. In contrast, metalation of NFP using an iridium(I)(cod) complex under an inert atmosphere resulted in the formation of a cod-isomerized (κ1 ,η3 -C8 H12 )-Ir complex.

Effect of melting condition on optical, FTIR and E.S.R properties of irradiated fluorophosphate glasses containing vanadium ions

Glasses from the system Na2O–CaF2–P2O5 with varying doping V2O5 (0.5, 0.75, 1%) were prepared under ordinary and reducing conditions. Multiple Characterizations including optical, FTIR and ESR spectral data were obtained for the prepared glasses before and after gamma irradiation (with a dose of 6 Mrad).Optical absorption spectrum of the undoped sample reveals strong and broad UV absorption with two peaks which are related to unavoidable traces of iron (Fe3+) ions contaminated within the chemicals used for the preparation of the glasses. The V2O5 doped glasses show two additional pronounced broad visible and near-IR bands which varied in intensity and position of their peaks with the V2O5 content and condition of melting. These distinct visible and near IR bands are assumed to be indicator for the presence for low valence trivalent and tetravalent vanadium ions with variable percents, in accordance with the included host fluoro-phosphate glass and different melting conditions. Gamma irradiation causes noticeable effect on the optical spectrum of the undoped glass but the spectra of V2O5-doped samples reveal pronounced shielding behavior. FTIR spectra of the prepared glasses show distinct vibrational bands due to asymmetric and symmetric vibrations of the phosphate groups of main (PO4) groups and together with the presence of some (PO3F) groups. The detailed FTIR spectra show minor variations with the V2O5 content or condition of melting. E.S.R results show distinct signals due to the presence of both trivalent and tetravalent vanadium ions which possess unpaired electrons in their outer electronic configurations. E.S.R data reveal limited variations in the intensity of the signals with varying V2O5 content or condition of melting and even upon gamma irradiation points out to the stability of V3+ and V4+ ions in the studied host fluorophosphate glass.

Origin of luminescence in Bi3+ - doped lanthanide niobates

Photoluminescence characteristics of the undoped and Bi3+-doped lanthanide niobates are investigated by the steady-state and time-resolved spectroscopy methods in a wide temperature range of 4.2–500 K. The broad visible emission bands with the large Stokes shifts are found to arise from the triplet relaxed excited states characterized by a small (∼1 meV) spin-orbit splitting energy. This indicates the exciton-like origin of all the observed emission bands. The data allow to conclude that the Bi3+-related triplet relaxed excited state is located inside the conduction band. No ultraviolet emission caused by the radiative decay of the triplet relaxed excited state of a Bi3+ ion is observed. The dependences of the emission intensity on the Bi3+ content indicate that the complex visible emission band of the Bi3+-doped niobates consists of two main, the higher-energy and the lower-energy, components arising from the excitons localized around the single Bi3+ ions and the {Bi3+ - Bi3+} dimers, respectively. The processes resulting in the appearance of the exciton-like emission under photoexcitation in the Bi3+-related absorption bands are discussed.

Effect of Al and Mg Co-doping on the Microstructural and Gas-Sensing Characteristics of ZnO Nanoparticles

Al and Mg co-doped ZnO nanoparticles were synthesized via the sol-gel technique to detect carbon oxides. The impact of Al and Mg on the structural, morphological and optical properties was discussed. XRD patterns revealed that Al and Mg ions successfully incorporate within the hexagonal crystalline structure of ZnO. The crystallites sizes of the samples heated at 400 °C ranges between 23 and 27 nm. TEM characterizations showed prismatic-like shape crystallites. Optical characterizations were carried out by UV-VIS-NIR spectroscopy and photoluminescence, showing high absorbance in the UV region and a slight decrease in energy band-gap compared to undoped ZnO. The PL spectra of all samples illustrated two major emissions including a broad visible band and a narrow ultraviolet (UV) band. Finally, it was confirmed that Al-Mg co-doping ZnO films promote carbon oxides sensing properties in terms of higher response, low detection limit and lower response/recovery time in comparison with undoped ZnO film.

Photochromic behavior of tungsten ions in sodium metaphosphate glass and effect of oxidizing condition assessed by spectroscopic analysis

Glasses based on sodium metaphosphate doped with WO3 were prepared in both normal and oxidizing conditions. Optical, FTIR, and ESR spectral studies were carried out to justify the photochromic behavior of such glasses. Spectral data of studied samples reveal strong UV absorption band that is linked to mandatory trace iron impurities while WO3-doped samples under ordinary melting conditions show an additional UV band is linked to hexavalent tungsten ions and also reveal two broad visible bands related to lower valence states of tungsten (W5+, W4+). FTIR spectral data reveal nearly repetitive vibrational bands due to constitutional main meta-phosphate building units with minor variations that are attributed to the presence of tungsten ions. ESR data of ordinary melted WO3-doped glasses confirm the presence of paired hexavalent tungsten ions with no distinct signals. The lower valences of tungsten ions are generated within oxidized samples and possess unpaired electrons giving characteristic ESR Signals.

Optical parameters, antibacterial characteristics and structure correlation of copper ions in cadmium borate glasses

Binary base borate glass of nominal composition (45CdO.55B2O3 mol%) and other samples containing up to 1.6 mol% CuO were successfully prepared using melt annealing route. Fourier transforms infrared (FTIR) spectra of the prepared glasses were studied to identify the structural building groups within the glasses and the role of Cu ions in the matrix arrangement.UV spectra of studied glasses reveal two intense narrow bands originally located at about 235 and 310 nm attributed for the presence of trace iron impurities present on the chemical used for preparation even in the ppm level. Additional analyzed broad visible band centered at about 780 nm appears in the spectra of CuO doped glasses and exhibit splitting at high CuO content. Optical energy gap and other physical parameters including refractive index, density, molar volume, molar refraction, electronic polarizability, and optical basicity reveal strong correlation with copper ion speciation.Both experimental and deconvoluted FTIR spectra of the studied glasses reveal characteristic absorption bands indicating the presence of both triangular and tetrahedral borate groups in their separate vibrational sites. The presence of Cu ions within the doping level is observed to cause no changes in the main characteristic IR bands but limited changes in the intensity of some bands and loosing of the splitting are observed.Antibacterial studies disclose diverse inhibition zone associated with an increase of CuO content and type of bacteria under examination connected with their activity index percent.

A Color Consistency Processing Method for HY-1C Images of Antarctica

The HY-1C satellite, as part of China’s optical satellite constellation for global ocean monitoring, monitors the ocean and coastal environment by the three broad visible bands of the Coastal Zone Imager (CZI) instrument. However, as a result of the sensor instrument noise, the atmospheric environment during imaging, and the shooting angle, the satellite images often show uneven illumination and inconsistent color between neighboring images. In this paper, according to the characteristics of the HY-1C CZI instrument, we propose a color consistency processing framework for coastal zone images of Antarctica. First of all, the high-frequency and low-frequency information of the image is separated by a statistical filter with simple clustering. The uneven lighting is then replaced by artificial lighting, which is globally uniform. Finally, the color difference between images is corrected by a color transfer method. In order to evaluate the color consistency results quantitatively, a new quantitative evaluation method is proposed. The experimental results for the coastal zone images of Antarctica show that the new processing framework can effectively eliminate the unevenness in the lighting and color. The mosaic results show a good performance in consistent lighting and tones, and the lack of visible mosaic lines proves the effectiveness of the proposed method. The quantitative evaluation analysis confirms the superiority of the proposed method over the Wallis method.

Comparative optical, FTIR and photoluminescence spectral analysis of copper ions in BaO–B2O3, SrO– B2O3 or Bi2O3– B2O3 glasses and impact of gamma irradiation

Three basic borate glasses were prepared from the systems (BaO–B2O3), (SrO–B2O3) and (Bi2O3–B2O3) together with samples doped with 0.25% CuO from the three systems. Collective characterizations of the optical, FTIR, photoluminescence spectra of the prepared glasses were carried out before and after impinging to gamma irradiation. The results were analysed in relation with the structural building groups and their housing in the glass network. Optical spectra of the alkaline earth borates reveal distinct UV absorption bands due to unavoidable trace iron impurities (Fe3+ ions). While the Bi2O3–B2O3 glass shows an additional near visible band related to absorption of Bi3+ ions. The CuO doped glasses exhibit distinct greenish blue colors imparting an additional very broad visible near IR band in all samples due to octahedrally coordinated Cu2+ ions. FTIR spectra of the two glass systems of (SrO–B2O3) and (BaO–B2O3) glasses display vibrational bands due to both BO4 and BO3 groups, while Bi2O3–B2O3 glass shows the interference of additional vibrational bands due to BiO6 and BiO3 groups. Photoluminescence spectra of the samples exhibited similar excitation and emission peaks for the three CuO-doped glasses. They are assumed to originate from the excitation of (3 d9 4s3d10) transitions in Cu2+ ions. Gamma irradiation caused some changes in all spectral measurements, and upon inclusion CuO doping no noticeable changes have been identified. Thermal expansion data were analysed and correlated with increasing the amplitude of atomic vibrations, field strength and bond strength of the cations with oxygen.

Charge separation of photosensitized phenothiazines for applications in catalysis and nanotechnology

Phenothiazines are a class of molecules that have been applied in antipsychotic therapy, photodynamic therapy, dyes, sunscreen, and more recently light-harvesting for energy applications. In the present study, the photochemical properties of phenothiazine aggregates were used for oxidative catalysis and synthesis of gold nanoparticles with potential applications in Boolean logic operations. Phenothiazines have the peculiar photochemical property, which is the stabilization of the photochemically-generated radical cation in their supramolecular aggregates. The phenothiazine radical cations exhibit pink color related to a broad visible spectral band with a peak at 520 nm. In the present study, the pair radical cation/reduced form of two phenothiazines, 10H-phenothiazine (PHT) and 3,7-bis (phenylamino) phenothiazine-5-iodide, named here phenoaniline (PHA) were photochemically generated and characterized by absorbance with a peak at the range of 520–550 nm, direct and spin-trapping EPR measurements. The radical cation was separated from the reduced form using the resin styrene-divinylbenzene copolymer containing iminodiacetate ions (Chelex 100®). The radical cation entrapped in the resin remained stable and could be used for catalytic oxidation processes. The reduced form remained in aqueous solution and had its reducing properties used to produce gold nanoparticles. Reduced PHT produced gold nanoparticles with dimensions around 7 nm that were arranged in monodispersed supramolecular aggregates of ~60 nm, stabilized by oligomerized phenothiazine, whereas PHA formed anisotropic gold nanoparticles. The supramolecular aggregates of AuNP PHT showed the potential to be applied in Boolean logic systems using CTAB dispersion and citrate reaggregation.

Effect of morphology and temperature treatment control on the photocatalytic and photoluminescence properties of SrWO4 crystals.

This work reports the combined effect of the morphology and crystallization degree of the strontium tungstate (SrWO4) scheelite structure on its photocatalytic and photoluminescence properties. The difference in the precursor ratio leads to two morphologies, spindle and sphere, which remain unchanged with heat treatment up to 500 °C. However, the crystallite sizes of the as-obtained samples and samples treated at 300 and 500 °C are about 50-74 nm for spindles and 44-110 nm for spheres. Both morphologies and thermal treatments lead to the variation in the photoluminescence and photodegradation of rhodamine (RhB) and methylene blue (MB) dyes under UV irradiation. A stronger photodegradation efficiency was found for RhB (90%) than for MB (72%). The photoinduced mechanism is more significant for RhB and becomes more efficient for samples treated at high temperature, while the photocatalysis of MB is weak due to the adsorption process. A broad visible photoluminescence band was observed at room temperature and chromaticity coordinates were identified, which confirmed the emission wavelength. The most intense photoluminescence was obtained for samples treated at 300 °C, corresponding to the optimal disordered structures and accompanied by a redshift wavelength for both spheres and spindles. In this case, the spindles showed the most intense photoluminescence, almost ten times higher than that in spheres.

ZnO colloids and ZnO nanoparticles synthesized by pulsed laser ablation of zinc powders in water

ZnO nanoparticles (NPs) were synthesized by pulsed laser ablation of zinc powders suspending in deionized water. The synthesized ZnO NPs were characterized for morphology, structure and optical properties. The ZnO NPs have irregular shapes sized in 10–50 nm and possess a wurtzite structure with polycrystallinity in nature, and grew without a preferential orientation. The supernatant solutions obtained by laser ablation of zinc powders in water exhibit the typical optical absorption edge of wurtzite ZnO near 380 nm and emit a photoluminescence composed of a narrow ultraviolet peak and a broad visible band, characteristics of the near-band-edge emission and the deep-level defects related emission of ZnO, respectively. The formation of ZnO NPs was further confirmed by structural and optical characterization performed for the aggregated ZnO NPs obtained by drop-casting the ZnO colloidal solutions onto Si wafers. And the effects of annealing in N2 on the structure and photoluminescence of the ZnO NPs transferred on Si were also examined.

A new far-red emission from Zn2SnO4 powder synthesized by modified solid state reaction method

In this work, far-red-emitting Zn2SnO4 phosphor has been successfully synthesized by a facile modified solid-state reaction method from ZnO and SnO2 powders. FESEM images reveal that as-milled particles are nearly spherical, with size in the range of 10–30 nm. The particle size increases with increasing annealing temperature and it reaches the value of about 4 μm at 1200 °C. XRD patterns indicate that Zn2SnO4 phase starts occurring at ~700 °C with its single phase at 900 °C and the best crystalline quality of Zn2SnO4 phase is obtained at 1000 °C. UV–Vis spectra analysis reveals that ZnO phase reappears at high annealing temperature (≥1100 °C), reflecting the deterioration of the single phase of Zn2SnO4. A broad visible band centered at 684 nm, which has never been explicitly reported, is clearly observed in the PL spectrum of the single Zn2SnO4 crystals. The intensity of this new band is influenced by annealing temperatures. It reaches the maximum value at 1000 °C, corresponding to the highest quality of the Zn2SnO4 phase. By using data fitting, the PL spectrum is deconvoluted into four Gaussian peaks at ~2.20 eV (563.5 nm), ~1.98 eV (626.1 nm), ~1.80 eV (688.8 nm), and ~1.68 eV (738.0 nm). The peak at ~2.20 eV (563.5 nm) is ascribed to oxygen vacancy (Vo) while the other emission peaks are possibly associated with a significant number of trapped states due to the high concentration of deficiencies such as oxygen vacant defects, zinc interstitials, zinc/tin vacancies (VZn/VSn), Zn/Sn stoichiometry or point defects.

Nd:YAG laser scribed zinc oxide on semi-flexible copper foils

In this work, a novel approach to synthesise zinc oxide (ZnO) directly on flexible copper substrates is proposed.The produced samples show a foam-like morphology made of agglomerates of small ZnO particles when processed at laser energy density of 18.0 J/cm2. On the other hand, the samples processed at higher beam energy density, i.e. 33.2 J/cm2, resulted in a more granular morphology, with some ZnO particles dispersed over the sample’s surface.Raman spectroscopy measurements demonstrated that this method resulted in the formation of wurtzite-ZnO crystalline phase in all samples. Room temperature photoluminescence spectroscopy analysis revealed the presence of a broad visible band in the orange-red region dominating the spectra, with a small contribution from the near band edge emission in the UV spectral region. Decreasing the beam energy fluence from 33.2 to 18.0 J/cm2 resulted in samples with higher overall visible band intensity, in line with what was observed for their crystalline quality. Moreover, the shift of the broad band maxima towards longer wavelengths could be an indication of the possibility of tuning the visible emission according to the chosen laser processing conditions.