Sign reversal of optical nonlinearities in glass-forming ionic liquid crystals containing nanoparticles

Liquid crystals are the materials of choice for a wide variety of conventional and emerging applications, including high-resolution displays for augmented and virtual reality, sensors, tunable lenses, filters and waveplates for advanced microscopy and super-resolution imaging, reconfigurable microwave devices, spatial light modulators for structured light generation and quantum technology, light shutters, light limiters, and optical valves. The creation of new liquid crystal composite materials and the study of their structure and physical properties are critical for the progress of the aforementioned technologies. This presentation reports on the optical and nonlinear-optical properties of glass-forming ionic liquid crystals. These materials are composed of metal-alkanoates and contain gold, carbon, or a combination of both gold and carbon nanoparticles. Z-scan measurements, conducted using nanosecond and femtosecond laser pulses, revealed a strong nonlinear-optical response. This response demonstrates the ability to change the sign of both the nonlinear absorption coefficient and the nonlinear refractive index of the samples by altering the duration and intensity of laser pulses, and by varying the composition of the studied samples.