Organic Optical Limiter with a Strong Nonlinear Absorptive Response

Abstract

Molecules with weak ground-state absorption that form strongly absorbing excited states can be used in optical limiters, which can protect sensors or human eyes from optical damage. Phthalocyanine complexes bearing heavy atoms or paramagnetic groups or in solvents containing heavy atoms show optical limiting enhanced by excited triplet-state absorption. A nonhomogeneous distribution of indium tetra( tert -butyl)phthalocyanine chloride along the beam path substantially enhances the excited-state absorption, yielding an optical limiter with a linear transmittance of 0.70 that can attenuate 8-nanosecond, 532-nanometer laser pulses by factors of up to 540.

Laser Confocal and Spatially-Resolved Fluorescence Spectroscopy of Porphyrin Distribution on Plasma Deposited Polymer Films

“…Porphyrins fixed on polymer surfaces are considered for possible applications and thermostabilization of polymers (especially metallo-porphyrins). [25] Samples "porphyrinpolymer", like tetrapyrrole compounds forming strongly absorbing excited states in solutions, [47,48] may be used as optical limiters, which can protect sensors or human eyes from optical damage. Concerning our interests, two practical questions (blood cleaning and optical limiters) based on these systems will be the subject of further thorough investigations.…”

Conjugated Molecules for the Smart Filtering of Intense Radiations

“…This model depicts the nonlinear absorber as a system having four main electronic levels involved in the transitions which give rise to an intensity-dependent absorption ( Figure 2). [30] (equivalent to σ exc / σ g with σ exc and σ g being the excited state and ground state absorption cross-sections, respectively), and the difference σ 24 − σ 13 [18] whose high values are indicative of better OL performances. Both σ 24 (or σ exc ) and σ 13 (or σ g ) are correlated with β as defined in equation 3, through the relationship [17]: seem more appropriate to accomplish the analysis of the OL performance in terms of the changes of the dipole moments implied in the various transitions associated with the nonlinear absorption processes [31].…”

Excitation of Highly Conjugated (Porphinato)palladium(II) and (Porphinato)platinum(II) Oligomers Produces Long-Lived, Triplet States at Unit Quantum Yield That Absorb Strongly over Broad Spectral Domains of the NIR

“…The additional requirements of a long excited-state lifetime, high resistance to degradative photochemistry, and large magnitude nonlinear optical (NLO) response have made identification of OPL candidates based on RSA for the NIR difficult. In contrast, a wide variety of optical limiting materials based upon phthalocyanine, [3][4][5][6][7][8][9][10][11] porphyrin, [12][13][14] fullerene, [15][16][17][18][19][20] carbon nanotube, 9,[21][22][23][24][25] nanoparticle, [26][27][28][29][30][31][32][33][34] and other [35][36][37][38][39][40] motifs have been identified for the visible spectral region. The limited number of potential NIR OPL materials 39,[41][42][43][44][45][46][47]…”