Thermally stable J-type phthalocyanine dimers as new non-linear absorbers for low-threshold optical limiters

Abstract

The possibility of developing new advanced optical limiters of laser radiation at 532 nm with low limiting thresholds has been demonstrated on thermally stable phthalocyanine J-type dimeric complexes of Mg, Zn, Cu, Ni, and Co. A new "threshold" model based on radiative transfer phenomena in nonlinear optical media was suggested for the exact definition of nonlinear absorption coefficient β and optical limiting threshold Ic. This model allows the determination of the optical characteristics of the limiter in the same active material with layers of different thicknesses, as well as the use of different parameters of laser radiation, such as cross-sectional spatial profiles of the laser beam and shapes of the laser pulse over time. The maximum value of the nonlinear absorption coefficient (β = 360 cm GW(-1)) and the lowest limiting threshold (Ic = 0.03 J cm(-2)) were estimated for a J-type zinc phthalocyanine dimer.

Cation-Induced Dimerization of Heteroleptic Crown-Substituted Trisphthalocyaninates as Revealed by X-ray Diffraction and NMR Spectroscopy

“…From the viewpoint of application, this alteration might be considered both a negative and a positive factor. For example, aggregation of Pc agents for photodynamic therapy quenches generation of singlet oxygen; however, recent studies show that it might pave the way to the application of aggregated Pc’s as sources of other reactive oxygen species or as agents for photothermal therapy. , The effect of aggregation on nonlinear-optical properties is also dual; examples of both impairment , and improvement , of optical limiting characteristics of Pc-based materials upon aggregation have been reported.…”

Slipped-cofacial J-type phthalocyanine dimers as potential non-linear absorbers for optical limiting applications

“…6c and d) by analogy with the investigations. 11,38 The results obtained show that in the visible range the OL effect for phthalocyanines 1-4 is most clearly observable. Non-linear absorbers demonstrate lower values of the limiting thresholds (0.1-0.3 W) and larger dynamic ranges compared to the near-IR region, where the limiting effect appears at higher input fluence (more than 1.5 W).…”

“…Due to the specific structure of the macrocyclic system, based on four fused isoindoline moieties, phthalocyanines show unique linear and non-linear optical (NLO) and photophysical properties, 1 wherein high thermal and chemical stability opens the possibility of utilising these compounds as chemical sensors, 2,3 semiconductors, 4 electrochromic display devices, 5,6 light emitting diodes, 7 photoconductors, 8 photosensitisers 9 and optical limiters. 10,11 Most investigations of phthalocyanines are carried out in organic or aqueous solutions, in which a tendency for uncontrolled aggregation is observed due to effective intermolecular contacts of the macrocycles. As a result, strong alterations in the spectral characteristics occur, giving rise to a decrease of light absorption, fluorescence quantum yields and a reduction of the photosensitising efficiency.…”

“…The output power was calculated as P out = P in  T(P), where T(P) = 10 ÀZ(P)L is the nonlinear transmittance: Z(P) -is the total absorption coefficient containing linear and nonlinear terms, L -is a layer thickness (was assigned to 0.1 cm). The linear transmittance was set to 70%, as in typical experiments 11.…”

Femtosecond nonlinear absorption and optical limiting action in nanoplatelet CuFe2O4-decorated rGO nanocomposites

“…Graphene possesses interesting nonlinear absorption and refraction properties because of the interband transitions that are independent of the broad wavelength. To improvise the nonlinearity with tunability, graphene oxides (cheaper alternates of graphene) are often decorated with noble metal atom, porphyrin, phthalocyanine or covalent functionalization groups [17][18][19][20]. The remarkable light absorption and broad band emission of oxide derivatives of graphene (GO-graphene oxide, rGO-reduced graphene oxide) due to extended π-conjugate system have shown significant interest in laser damage protecting units.…”