Ultrafast Nonlinear Optical Characteristics of Pyrene-Conjugated Azaphthalocyanines with Optical Limiting Behavior

Abstract

We synthesized an efficient dual-directional multivalent pyrenebearing azaphthalocyanine conjugate (AzaPc−pyrene) and alkyne-terminated azaphthalocyanine (AzaPc1). The ultrafast nonlinear optical characteristics of these macrocycles were studied using a near-infrared femtosecond (fs) Z-scan experiment. The results for these Pc solutions showed good nonlinear optical coefficients, low optical limiting threshold (38 mJ/cm 2 ), and a good set of figures of merit that satisfied the criteria for optical switching materials, thus proving their usefulness in photonic applications. Comparison with other phthalocyanines showed that both AzaPc−pyrene and AzaPc1 are strong nonlinear optical materials. The most important outcome of our study was a huge enhancement in the nonlinear absorption value of AzaPc−pyrene in the film phase that was up to 10 5 times greater than the corresponding values for AzaPc1 solutions; this enhancement was established using ultrafast laser irradiation-induced deformations in AzaPc−pyrene-embedded PMMA films, whereas the AzaPc1 film showed saturable absorption behavior. A promising limiting threshold of 1.5 mJ/cm 2 with very low linear absorption was achieved in the deformed pyrene-incorporated AzaPc films; this is lower than the previously reported values for highly nonlinear materials, making these materials as potential nonlinear optical materials in the near-infrared wavelength range.

Optical, Electrochemical, Third-Order Nonlinear Optical Investigations of 3,4,5-Trimethoxy Phenyl Substituted Non-Aqueous Phthalocyanines

“…Two-photon absorption coefficients of ∼10 −13 cm/W were reported for phthalocyanine porphyrin conjugates metalated with nickel by Xiao et al, 2016. Interestingly, n 2 values with magnitudes of 10 −16 cm 2 /W were reported recently for pyrene-conjugated azaphthalocyanines (Sebastian et al, 2020) and pyrene-conjugated Zinc(II)phthalocyanines (Husain et al, 2021), respectively. However, they observed strong three-photon absorption in the open aperture data.…”

Three-photon-induced singlet excited-state absorption for tunable ultrafast optical-limiting in distyrylbenzene: a first-principles study

“…36 It is noticed that the biological materials and atmosphere have a low absorption coefficient at this wavelength, therefore the light with this wavelength has many potential applications in fields such as military, industry and medical equipment. 8 It should also be mentioned that Sebastian et al 17 show that the substituted azaphthalocyanines and pyrene-incorporated azaphthalocyanines also show the optical-limiting effects for the femtosecond-scale laser (90 fs) pulses at the near-infrared wavelength of 800 nm due to the two-photon-induced singlet excited-state absorption.…”

“…12–16 Consequently, both ground and excited state absorption are important for understanding optical-limiting effects. 17–21…”

Ring Opening of Triflates Derived from Benzophospholan-3-one Oxides by Aryl Grignard Reagents as a Route to 2-Ethynylphenyl(diaryl)phosphine Oxides

“…The “click-type” reactions of ethynyl compounds have also been exploited to synthesize π-conjugated macromolecules for organic electronics 11 and other materials. 12 On the other hand, ethynyl compounds themselves, especially those possessing expanded π-systems, have been involved in the preparation of organic structures for photo-optical purposes and others. 13 All mentioned applications of alkynes benefit from the rapid development of the synthetic routes, enabling the incorporation of an ethynyl unit into the structure of nearly any organic molecule.…”

“…Furthermore, an alkyne functionality is frequently used in medicine and chemical biology as a “click” probe to label or identify molecular targets and to assess target engagement. The “click-type” reactions of ethynyl compounds have also been exploited to synthesize π-conjugated macromolecules for organic electronics and other materials . On the other hand, ethynyl compounds themselves, especially those possessing expanded π-systems, have been involved in the preparation of organic structures for photo-optical purposes and others .…”