DIEGO SILVERIO DA SILVA

DIEGO SILVERIO DA SILVA

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Double line Neodymium doped GeO2-PbO waveguide amplifier for the second telecom window
2020 - WETTER, NIKLAUS U.; SILVA, DIEGO S. da; KASSAB, LUCIANA R.P.; ROSSI, WAGNER de
We report the production of active double waveguides in germanate glasses, GeO2-PbO doped with Nd3+, by direct femtosecond laser writing. The glasses were produced using the melt-quenching technique and the active waveguides were written using 30 fs laser pulses at 800 nm with different parameters of writing speeds and pulse energies depending on the rare earth elements used for doping. The photo-induced refractive index change was 5.2x10-3. The Nd doped sample exhibited a relative gain of 3.6 dB/cm for 1.6 mW of 805 nm pump power. The results obtained in present work demonstrate that Nd3+ doped GeO2-PbO glasses are promising materials for the fabrication of integrated amplifiers, lossless components and lasers based on germanate glasses.
Double line waveguide amplifiers written by femtosecond laser irradiation in rare-earth doped germanate glasses
2020 - SILVA, DIEGO S. da; WETTER, NIKLAUS U.; KASSAB, LUCIANA R.P.; ROSSI, WAGNER de; ARAUJO, MARIANA S. de
We report the production of active double waveguides in Er/Yb doped GeO2-PbO glasses, by direct femtosecond laser writing. The glasses were produced using the melt-quenching technique and the active waveguides were written using 30 fs laser pulses, at 800 nm, with writing speed of 0.06 mm/s and pulse energy of 32 μJ. The photo-induced negative refractive index change was of 􀀀 7.4 � 10􀀀 3. The Er/Yb doped sample showed a relative gain (signal enhancement of 7.5 dB/cm, for 105 mW of 980 nm pump power. The relative gain compensates both, the propagation losses and the absorption losses, and a positive maximum internal gain of 4.6 dB/cm can be obtained at the signal wavelength of 1550 nm. The results obtained in present work demonstrate that Er/Yb glasses are promising materials for the fabrication of integrated amplifiers, lossless components and lasers based on germanate glasses.
Production of a microfluidic random laser using ultrashort laser pulses
2019 - WETTER, NIKLAUS U.; GOMES, ANTONIO A.; SILVA, DIEGO S. da; ROSSI, WAGNER de
A random rhodamine laser system is produced on board of a femtosecond laser machined microfluidic system. When pumped by a nanosecond pulsed laser beam at 532 nm, laser emission at 610 nm is observed together with the linewidth narrowing typical of random lasers. The system can be easily integrated as an optofluidic component into microfluidic circuits for assessment of optical parameters on board of the lab-on-chip.
Influence of silicon nanocrystals on the performance of Yb3+/Er3+: Bi2O3-GeO2 pedestal waveguides for amplification at 1542 nm
2018 - SILVA, DIEGO S. da; ALAYO, MARCOS I.; KASSAB, LUCIANA R.P.; ASSUMPCAO, THIAGO A.A. de; WETTER, NIKLAUS U.; JIMENEZ-VILLAR, ERNESTO
This paper reports for, the first time, the influence of silicon nanocrystals on the photoluminescence and optical gain of Yb3+/Er3+ codoped Bi2O3–GeO2 waveguides for amplification at 1542 nm. Pedestal waveguides were fabricated by RF- sputtering followed by optical lithography and reactive ion etching. RF-sputtering followed by heat treatment produced silicon nanocrystals with average size of 8 nm and resulted in a photoluminescence enhancement of about 10 times for the 520 nm and 1530 nm emission bands. The resulting internal gain was 5.5 dB/cm at 1542 nm, which represents and enhancement of ~50%, demonstrating potential for applications in integrated optics.
Tunable green/red luminescence by infrared upconversion in biocompatible forsterite nanoparticles with high erbium doping uptake
2018 - ZAMPIVA, RUBIA Y.S.; ACAUAN, LUIZ H.; VENTURINI, JANIO; GARCIA, JOSE A.M.; SILVA, DIEGO S. da; HAN, ZHAOHONG; KASSAB, LUCIANA R.P.; WETTER, NIKLAUS U.; AGARWAL, ANURADHA; ALVES, ANNELISE K.; BERGMANN, CARLOS P.
Nanoparticles represent a promising platform for diagnostics and therapy of human diseases. For biomedical applications, these nanoparticles are usually coated with photosensitizers regularly activated in a spectral window of 530–700 nm. The emissions at 530 nm (green) and 660 nm (red) are of particular interest for imaging and photodynamic therapy, respectively. This work presents the Mg2SiO4:Er3+ system, produced by reverse strike co-precipitation, with up to 10% dopant and no secondary phase formation. These nanoparticles when excited at 985 nm show upconversion emission with peaks around 530 and 660 nm, although excitation at 808 nm leads to only a single emission peak at around 530 nm. The direct upconversion of this biomaterial without a co-dopant, and its tunability by the excitation source, renders Mg2SiO4:Er3+ nanoparticles a promising system for biomedical applications.
Femtosecond laser-written double line waveguides in germanate and tellurite glasses
2018 - SILVA, DIEGO S. da; WETTER, NIKLAUS U.; ROSSI, WAGNER de; SAMAD, RICARDO E.; KASSAB, LUCIANA R.P.
The authors report the fabrication and characterization of passive waveguides in GeO2–PbO and TeO2–ZnO glasses written with a femtosecond laser delivering pulses with 3μJ, 30μJ and 80fs at 4kHz repetition rate. Permanent refractive index change at the focus of the laser beam was obtained and waveguides were formed by two closely spaced laser written lines, where the light guiding occurs between them. The refractive index change at 632 nm is around 10-4 . The value of the propagation losses was around 2.0 dB/cm. The output mode profiles indicate multimodal guiding behavior. Raman measurements show structural modification of the glassy network. The results show that these materials are potential candidates for passive waveguides applications as low-loss optical components.
Production and characterization of femtosecond laser-written double line waveguides in heavy metal oxide glasses
2018 - SILVA, DIEGO S. da; WETTER, NIKLAUS U.; ROSSI, WAGNER de; KASSAB, LUCIANA R.P.; SAMAD, RICARDO E.
We report the fabrication and characterization of double line waveguides directly written in tellurite and germanate glasses using a femtosecond laser delivering 30 mu J, 80 fs pulses at 4 kHz repetition rate. The double line waveguides produced presented internal losses inferior to 2.0 dB/cm. The output mode profile and the M-2 measurements indicate multimodal guiding behavior. A better beam quality for the GeO2 - Pbo waveguide was observed when compared with TeO2 - ZnO glass. Raman spectroscopy of the waveguides showed structural modification of the glassy network and indicates that a negative refractive index modification occurs at the focus of the laser beam, therefore allowing for light guiding in between two closely spaced laser written lines. The refractive index change at 632 nm is around 10(-4), and the structural changes in the laser focal region of the writing, evaluated by Raman spectroscopy, corroborated our findings that these materials are potential candidates for optical waveguides and passive components. To the best of our knowledge, the two double line configuration demonstrated in the present work was not reported before for germanate or tellurite glasses.
Production and characterization of Femtosecond laser-written waveguides in a tellurium-zinc glass
2016 - SILVA, DIEGO S. da S.; X, JONATA; ROSSI, WAGNER de; KASSAB, LUCIANA R.P.; WETTER, NIKLAUS U.