Nonlinear Optical Limiters Research Articles

Step by Step Bisacrificial Templates Growth of Bimetallic Sulfide QDs‐Attached MOF Nanosheets for Nonlinear Optical Limiting

AbstractHere, the authors first report a bimetallic sulfide quantum dots (QDs)‐attached metal–organic framework (MOF) nanosheets‐based film from bisacrificial templates. By using a step by step bisacrificial templates strategy, MOF CuBDC precursors (BDC = 1,4‐benzenedicarboxylate) and chalcogenidometalates as the templates can successfully in‐situ assemble Cu2SnS3 (CTS) QDs‐attached CuBDC nanosheets on the functionalized substrate (CTS @ CuBDC film). The obtained CTS QDs possess a uniform size with ≈6.2 nm and are homogeneously dispersed on MOF nanosheets, which results in an improvement of conductivity and represents a semiconductive composite film for optical application. A Z‐scan study under the excitation of a 532 nm laser shows that the CTS @ CuBDC film possesses strong optical limiting (OL) behavior and very low OL thresholds (0.92 J cm−2) as well as large third‐order nonlinear susceptibility (1.9 × 10−6 esu). This work suggests that the step by step bisacrificial templates method is a fascinating and feasible strategy to prepare metal sulfide QDs dispersed MOF hybrid materials, and provides a promising potential candidate for nonlinear optical applications.

Optical behaviour of nematic liquid crystal doped with carbon dot in the nonlinear optical regime

We delve into the effect of carbon dot (c-dot) doping at different concentrations (0.1, 0.2, 0.4, and 1 wt%) on the third order nonlinear optical properties of a nematic liquid crystal (NLC). C-dots were synthesized by the thermal decomposition of ammonium citrate salt. The size and morphology of prepared c-dots were confirmed by the TEM micrograph. Nonlinear optical properties of c-dot doped liquid crystal were investigated by the z-scan method using a Q-switched Nd: YAG laser delivering 7 ns pulse at 532 nm wavelength. A phenomenal increase in the nonlinear absorption coefficient, βeff, was observed for 0.2 wt% c-dot doped liquid crystal. There is an enhancement in the value of third order susceptibility, χ(3), of the order of 10 for the doped liquid crystal. An increase in the third order nonlinear optical absorption coefficient implies a better optical limiting characteristic than the pristine LC. The optical limiting threshold value of 0.2 wt% c-dot doped LC is found to be 1.23 J/cm2. We determine for the first time that c-dot doping in NLC leads to a significant improvement of the nonlinear optical properties compared to pure LC. The results indicate that the system under study could be a promising candidate for nonlinear photonic devices and optical limiters.

Giant Optical Nonlinearities of Photonic Minibands in Metal–Dielectric Multilayers

The giant nonlinear optical responses of photonic minibands of (Ag/SiO2)4 metal–dielectric multilayers are reported using high intense femtosecond laser pulses. Ag and SiO2 alternative stack of layers form a series of coupled Fabry–Pérot resonators (Ag–SiO2–Ag) and the cavity modes are split into transmission minibands in the metal reflective spectral region. The strong saturation of two‐photon absorption associated with multiphoton absorption (MPA) is observed at photonic miniband minimum (≈700 nm), whereas MPA is the strong dominant nonlinearity at peak maximum (≈725 nm). The metal‐cavity induced manifold enhancement (>103 times) in the Ag intrinsic nonlinearity follows wide miniband spectral (700–765 nm) trend. Results are discussed with respect to single (Ag/SiO2)1 and bare Ag thin film results. The broad origin of giant nonlinearity is ascribed to the strong local cavity field enhanced metal interband transitions initiated by multiphoton absorption processes. The strong confinement of optical field and energy dissipation within these metal–dielectric coupled resonators are further evidenced by transfer matrix method simulations. The giant multiphoton absorptive type nonlinearities with very high laser‐damage threshold (≈50 GW cm−2) from these composite transparent metals are potentially beneficial for novel nonlinear optical limiters, optical Bragg coatings, and saturable optical absorbers for extremely high‐power ultrafast lasers operation.

Effects of Size and Oxidation on the Nonlinear Optical Response and Optical Limiting of Graphene Oxide Sheets

In the present work we report on the effect of the size and the degree of oxidation on the third-order nonlinear optical response and the optical limiting action of water dispersed graphene oxide (...

Cobalt Enhanced Nonlinear Optical Properties and Optical Limiting of Zinc Oxide Irradiated by Femtosecond Laser Pulses

Cobalt Enhanced Nonlinear Optical Properties and Optical Limiting of Zinc Oxide Irradiated by Femtosecond Laser Pulses

Nonlinear Optical Properties and Optical Limiting of Ag Nanoparticle Prepared by Laser Ablation

Nonlinear Optical Properties and Optical Limiting of Ag Nanoparticle Prepared by Laser Ablation

Nonlinear Optical Properties, Optical Limiting and Optical Switching of Ag Nanoparticles Prepared by a Green Synthetic Method

Silver nanoparticles were synthesized using an aqueous extract of cinnamon berks (cinnamon cassia) as a reducer and stabilizer. The synthesized silver nanoparticles were characterized using UV-Vis spectrometry and Transmission Electron Microscopy (TEM), which revealed the nano nature of the particles. Nonlinear absorption and nonlinear refraction were measured using a Z-scan technique at different wavelengths with CW lasers. The third order nonlinear susceptibility was found to be between (1.5 to 22) × 10-14 m2/V2. The nonlinear property of the synthesized silver nanoparticles was used to demonstrate optical limiting and all-optical switching. An optical limiting threshold was found to be 0.1 mW at 632.8 nm.

A new-type composite film of cholesteric liquid crystal doped with PCBM for laser-damage prevention in both visible and near-infrared region

ABSTRACTNowadays, with the increasing use of high-power laser, research and development of laser-damage prevention materials with multifunctional features and wideband wavelengths are urgent and indispensable. In the paper, cholestric liquid crystal (ChLC) is first proposed to be doped with a high-efficiency optical limiting material, 6, 6-phenyl C61-butyric acid methyl ester (PCBM), to fabricate a new-type laser-damage-prevention film. The ChLCs have the desired reflection wavelengths covering 750–2300 nm, which is an effective and potential candidate for the prevention of continuous or tuneable laser in near infrared (NIR) region. Meanwhile, the solubility of PCBM in LC and its nonlinear absorption property of are discussed, and it was proved that the good solubility of PCBM in LC contributed to the excellent nonlinear absorption of mixture (LC doped with PCBM). Taking advantages of this phenomenon, a novel composite film of ChLCs doped with PCBM is prepared by UV polymerization. As a result, the composite film not only performs broadband reflection in NIR region, but also exhibits a strong nonlinear absorption and excellent optical limiter properties in visible region, which proves the film's potential application in laser damage prevention.

Nonlinear optical limiter of pulsed laser radiation based on potassium–aluminum–borate glass with copper chloride nanocrystals

This paper discusses the nonlinear optical properties of copper-containing potassium–aluminum–borate glass when it is acted on by a pulsed laser with wavelength 532 nm and pulse width 5 ns. It is shown that the nonlinear optical limiting threshold of the original copper-containing glass is 3×10−3 J, while that of glass with copper chloride nanocrystals is 5×10−6 J. It is shown that the maximum attenuation of a transmitted laser pulse with energy 0.05 J is a factor of 100 for the original glass with transmission 85%, while it is a factor of 1000 for glass with copper chloride nanocrystals and transmittance 70%. It is concluded that potassium–aluminum–borate glasses with copper chloride nanocrystals can be used as filter–limiters for the protection of the organs of vision and photodetectors from pulsed laser radiation.

Elimination of bleaching in a material based on aqueous fluid with carbon nanoparticles for optical limiters

The possibilities of correcting the functional properties of nonlinear optical limiters based on carbon nanoparticles using polymer dopants have been considered. The results of analyzing the characteristics of nonlinear optical limiting of a suspension of carbon black with addition of sodium dodecylbenzene sulfonate and polyvinyl alcohol are given. The forms in which particles exist in the suspension have been investigated by different physicochemical methods. Optical measurements have confirmed the efficiency of these additives.

Nonlinear optical limiters of pulsed laser radiation based on carbon‐containing nanostructures in viscous and solid matrices

Results of the study of optical limiters of pulsed laser radiation based on nonlinear effects in carbon nanostructures placed into viscous and solid matrices are presented. A nonlinear optical limiting was studied by nanomaterials based on multi‐wall polyhedral carbon nanostructures (astralens) placed in a sol–gel matrix. Similar studies for single‐wall and multi‐wall carbon‐containing nanotubes placed in polymer matrices with various viscosities were performed. No additional mechanism of optical limiting due to electron structure of single‐wall carbon‐containing nanotubes at their introduction into viscous and solid composite media was found. An influence of polymer matrix composition containing carbon nanotubes (CNTs) on a threshold and ratio of attenuation of laser radiation was demonstrated. The best limiting characteristics were observed at placing CNT into polymethylsiloxane matrix. An effect of “self‐healing” of a medium after laser radiation passage through high viscous liquids was obtained. The high parameters of nonlinear optical limiting (the threshold of limiting 10−5 J, ratio of attenuation 103) achieved for the composite material CNT (HiPCO High‐Pressure Carbon Monoxide) and carbon nanofibers in high viscous and solid polymethylsiloxane media allow the design of protective filters for laser radiation operating in wide spectral range. Copyright © 2014 John Wiley & Sons, Ltd.

Nonlinear Optical Properties and Optical Limiting Measurements of {(1Z)-[4-(Dimethylamino)Phenyl]Methylene} 4-Nitrobenzocarboxy Hydrazone Monohydrate under CW Laser Regime

We report results from the investigation of the nonlinear refractive index and nonlinear absorption coefficient of {(1Z)-[4-(Dimethylamino)phenyl]methylene} 4-nitrobenzocarboxy hydrazone mono-hydrate (DMPM4NBCHM) solution using Z-scan technique with a continuous wave (CW) Argon ion laser. The results show that this type of organic material has a large nonlinear absorption and nonlinear refractive index at 488 nm and 514 nm. The origin of the nonlinear effects was discussed. We demonstrate that the light induced nonlinear refractive index variation, leads to limiting effect. The results indicated that DMPM4NBCHM could be promising candidates for application on nonlinear photonic devices and optical limiters.

Formation and evolution of far-field diffraction patterns of divergent and convergent Gaussian beams passing through self-focusing and self-defocusing media

The formation and the evolution of the far-field patterns of the Gaussian beams passing through a thin self-focusing medium and a thin self-defocusing medium are studied using the Fresnel–Kirchhoff diffraction theory, and the effects of the different Kerr media and the different Gaussian beams on the far-field pattern formation and evolution are analysed by taking into consideration both the change in the additional phase shift induced by the refractive index and the change in the sign of the radius of wavefront curvature of the laser beam passing through the nonlinear medium. Our results show that, when either the divergent Gaussian beam passes through the self-defocusing medium or the convergent Gaussian beam passes through the self-focusing medium, the far-field intensity distribution pattern is a series of thick diffraction rings with a central dark spot; while, when either the divergent Gaussian beam traverses the self-focusing medium or the convergent Gaussian beam traverses the self-defocusing medium, the far-field intensity distribution pattern is a series of thin diffraction rings with a central bright spot. Our results also show that whether the central dark spot or the central bright spot occurs depends mainly on the sign of the product of the additional phase shift and the radius of the wavefront curvature. When the sign is negative, that is, when the divergent Gaussian beam passes through the self-defocusing media, or the convergent Gaussian beam passes through the self-focusing media, the central dark spot surrounded by the thick diffraction rings will emerge in the far field; while, when the sign is positive, that is, when the divergent Gaussian beam traverses the self-focusing media, or the convergent Gaussian beam passes through the self-defocusing media, the central bright spot with the thin diffraction rings will occur in the far field. The difference between the diffraction patterns is attributed to the interplay of the strong spatial self-phase modulation caused by the refractive index change of the medium and the changes in sign of the radius of the wavefront curvature of the incident Gaussian beam. The results obtained in this paper are of significance to the design of practical nonlinear optical limiters for the eye or sensor protection and many other applications.

Nonlinear optical limiter and digital optical switch by cascaded nonlinear couplers: analysis

In this paper, an all-optical digital switch and a limiter are proposed and analyzed, both of which consist of several nonlinear directional couplers in series. These two devices utilize the nonlinear restraining effect of the nonlinear coherent coupler on its input power. In the devices, the OFF-ON extinction ratio, the output power fluctuation and the dynamic switching range all decrease with the number of the couplers in series increasing, and the output power level can be adjusted by varying the coupling length. The characteristics of these devices with different structures are discussed, and the numerical results show that the OFF-ON extinction ratio and the dynamic switching range of the optical switches can be less than -90 dB and 0.03P/sub c//100, respectively, and that the fluctuation of the limiting output power of the optical limiter can be less than 10/sup -7/P/sub c/.

Electro-Optic Power Limiter: Broadband, Self-Actuating Optical Limiter for Visible and Infrared Radiation

AbstractWe present studies of an optical power limiter that uses a combination of the photoconductive and linear electro-optic effects. The electro-optic power limiter (EOPL), first demonstrated using CdTe in the near IR, possesses many desirable qualities including broadband wavelength responsivity, self-actuation, and low threshold power. One unique capability of EOPL, not found in any other nonlinear optical power limiter, is the fact that any light - coherent or incoherent - can be used. Our studies in CdTe, GaAs, and BSO crystals resulted in extending the wavelength range from the visible to MWIR wavelengths.

Saturable transmission by multiphoton absorption in semiconductors

Multiphoton absorption can set an intrinsic upper limit to the power density that can be transmitted through semiconductors. This mechanism is an effective means of optically pumping semiconductor laser and can limit the power density from such devices, or can enable the fashioning of nonlinear optical power limiters.