High-Performance Optical Power Limiting Filters at Telecommunication Wavelengths: When Aza-BODIPY Dyes Bond to Sol–Gel Materials

Abstract

An optical power limiter (OPL) device can change its optical properties depending on the input light intensity: it is ideally transparent at low incident power and presents a decrease in transmission when the incident intensity increases. This phenomenon can be used for protection of optical sensors. This paper presents the design of a functionalized aza-BODIPY chromophore, combining good nonlinear two-photon absorption and exited-state absorption in the short-wave infrared range (1300−1600 nm). The aza-BODIPY chromophores also show excellent thermal and photochemical stabilities. Their covalent grafting to a sol−gel matrix leads to the formation of class II sol−gel materials that allows for extraordinary doping concentrations of up to 280 mol•L −1 (40 wt %), which results in highly efficient OPL performances at 1550 nm.

Near-infrared dyes for two-photon absorption in the short-wavelength infrared: strategies towards optical power limiting

“…357 Solid state OPL performances using aza-bodipys were further improved with class-II sol-gel materials where the covalent grafting of dye 182 permitted to greatly increase the maximum dye concentration in the matrix up to 40 wt.%, resulting in strong enhancement of the OPL performances, with a 50% transmission reached for an input fluence of 5 J cm -2 (Figure 67). 358 Figure 67 Top: structure of functionalized aza-bodipy 182. Bottom: optical limiting performances for sol-gel materials at 1550 nm with dye 182 (blue dots, grafted at a 40 wt.% ratio) and dye 113 (black dots, doped at a 5 wt.% ratio) under the same irradiation conditions (5 ns pulses).…”

“…The picture represents a typical class II xerogel obtained by grafting of dye 182 in a sol-gel matrix. Adapted with permission from reference 358 . Copyright 2020 American Chemical Society.…”

Enhanced Two–Photon Absorption and Promising Broad Energy Range Optical Power Limiting Properties ofTransoidandCisoidBenzodipyrrolenine-Fused Squaraine Dimers

“…Squaraine dyes show intense near-IR absorption and emission and strong nonlinear response, which make them ideal candidates for photonic materials in several potential applications. − Furthermore, owing to the rather simple synthetic access of a great variety of monomeric, oligomeric, − and polymeric − squaraine dyes, there are extensive possibilities to design a range of superchromophores with tuneable optical properties. Therefore, these organic dyes play an important role in diverse applications such as imaging, nonlinear optics, biological labeling, and more. − In particular, fluorescent dyes that can be excited by the simultaneous absorption of two near infrared (NIR) photons are highly sought after for bioimaging because biological tissue is transparent in the NIR and scattering is strongly reduced for photons with long wavelengths. , Another nonlinear optical application that has attracted much interest is optical power limiting of NIR photons for protection of human eyes or optical sensors from intense laser irradiation, optical pulse processing, or laser mode locking. − It is a prerequisite for such applications that the material possesses a high transmission of low intensity near-IR light and a high extinction coefficient at high intensities, greater than an optical limiting threshold. Thus, one of the requirements for optical limiting applications is a high two-photon absorption (2PA) probability at the wavelength of interest.…”

Plasmonic Bipyramidal Au Nanoparticles Enhance Near-Infrared Nonlinear Absorption of Dyes Confined in Sol–Gel Materials: Implications for the Safe Utilization of Lasers

“…Most of the reported monolithic materials, for visible wavelengths applications are based on organic polymers, 5,8,[22][23][24][25][26] sol-gel hybrid glasses [27][28][29][30][31][32][33][34][35][36][37][38] or sodium−zinc borate glass doped with gold nanoparticles.To the best of our knowledge the two only reports on 3D monolithic solid-state nonlinear optical limiters, operating in the short-wave infrared (SWIR), which is a promising range for the development light detection and ranging (LIDAR) systems working at the eye safe wavelength of 1550 nm, are by our group, on sol-gel derived materials. [39][40] In most cases, silica based matrices are favoured over organic polymer matrices due to higher damage threshold and nonlinear parameters (n2, β, Re[χ (3) ], Im[χ (3) ]). 16,41 Low compatibility and solubility of dyes in the sol-gel host matrices is often a limitation since the optical performances are concentration dependent.…”

“…This limitation can be overcome by silanization of dopants to highly improve their concentration through strong covalent bonding between the dyes and the matrix. 30,32,33,40,[42][43][44] Another alternative to improve the optical performance is to use plasmon enhanced optical limiting. This strategy have already proven to be of high efficiency in the visible wavelength but has never been demonstrated so far in the SWIR.…”