Driving Third-Order Optical Nonlinearities in Photoluminescent Si Nanoparticles by Nitrogen Co-Implantation in a Silica Matrix

Abstract

The photoluminescence and third-order nonlinear optical effects of co-implanted silicon nanoparticles and nitrogen ions in a silica matrix were studied. Experimental evidence shows the potential of nitrogen ions for changing optical properties exhibited by silicon nanoparticles implanted in an integrated system. The modification of the optical bandgap and photoluminescent intensity in the studied nanomaterials by the incorporation of nitrogen was analyzed. Standard two−wave mixing experiments were conducted using nanosecond and picosecond laser pulses at 532 nm wavelength. At this off-resonance condition, only multiphoton excitation can promote electrons at energies above the optical bandgap of the silicon nanoparticles. The picosecond results show that the co-implanted sample with nitrogen exhibits a three-fold enhancement of the nonlinear Kerr response. Femtosecond z-scan measurements were undertaken at 800 nm in order to explore the modification of the ultrafast nonlinear response of the samples that revealed a purely electronic Kerr nonlinearity together to saturable absorption of the SiNPs in the near-infrared. Remarkably, femtosecond results reveal that nitrogen co-implantation in the SiNPs system derives from the quenching of the third-order nonlinear optical behavior. These findings pointed out a simple approach for engineering the optical bandgap of nanocomposites, which can be controlled by a doping process based on ion-implanted nitrogen. It is highlighted that the enhanced light-matter interactions induced by nitrogen implantation can be useful for developing nonlinear integrated silicon photonics nanodevices with low power excitation.

Fabrication of Quasi-Sinusoidal Surface Relief Optical Transmission Gratings in Pyrex and IOG Glasses by Implantation with Oxygen and Nitrogen Ion Microbeams of the 5–6 MeV Energy Range

“…As explained in Chapter 1.2, according to our earlier results on the fabrication, the optical gratings by implantation through a mask, lateral straggling rendered the finest diffraction gratings of a grating constant of 4 μm quasi-sinusoidal. 33 Since the lateral dimensions of the ion microbeams used in our actual experiments were in the range of 1.5−2.4 μm, we could expect quasi-sinusoidal grating profiles when writing "binary" gratings with the microbeams. In other words, writing single stripes separated by a grating constant of 3−5 μm would result in quasi-sinusoidal grating profiles.…”

“…It was found that the implantations did not increase the absorption of the glass samples at visible wavelengths. Based on the measured amplitudes of the surface relief gratings and the diffraction efficiencies, and on the comparison of the implantation parameters of the actual experiment to the previous ones, where implantation through mask was performed, 33 it was concluded that the strength of the implanted index-of-refraction gratings was negligible compared to that of the surface relief one. Diffraction efficiency measurements were repeated with the incoming laser beam polarized parallel to the plane of incidence.…”

“…Later, it was also proved that modulation of the optical path across the gratings was mainly due to the ion beam implantation induced surface relief (around 80%), and the rest was due to the changes in the refractive index (around 20%). 33 In the case of the finest gratings with 4 μm grating constant, the surface relief profile was found to be quasi-sinusoidal. This fact was attributed to the lateral straggling of the implanted ions.…”

“…This fact was attributed to the lateral straggling of the implanted ions. 33 It must be noted that the above review of previous research was focused on the modifications most relevant to the research presented in this review, where the target materials were glasses. As mentioned earlier, other properties, such as photoluminescence and optical nonlinearity of crystals, could also be modified by ion beam implantation.…”

Promotional effects of cerium in ytterbium doped fibers on proton irradiation damage

“…According to ref. 26, instant changes in nonlinear optical properties occur promoted by nitrogen irradiation. The incorporation of N inside the host matrix containing the SiNPs slightly changes the effective optical bandgap of the nanocomposite from 4.5 eV to 4.9 eV.…”