On the optical limiting and Z-scan of hexamethylin-dotricarbocyanine perchlorate dye

Measurement of Reverse Saturable Absorption (RSA) and optical limiting response in hexamethylin-dotricarbocyanine perchlorate (HITC perchlorate) is reported for the first time and results are compared with C60 and various other dyes under the nanosecond pulse excitation. HITC perchlorate shows better optical limiting than well known C60 and results reveal that photo-excited triplet state absorption cross-section is higher than the ground state absorption cross-section, suggesting the presence of Reverse Saturable Absorption (RSA) in these materials. Limiting threshold for HITC perchlorate is 0.45 J/cm2 (at 70% linear transmission), which is lower than C60 (1.2 J/cm2, at 70% linear transmission). Z-scan shows negative nonlinearity (self-defocusing) for HITC perchlorate. Ethanol soluble and low cost HITC perchlorate displaying better optical limiting as compared to other conventional materials. Absence of photochemical or photothermal destruction processes in the studied materials suggests their perspective application as a stable optical limiter in photonic devices.