Microfluidic Femtosecond Laser-Induced Nucleation of Supersaturated Aqueous Sodium Chlorate Solutions

Femtosecond laser-induced crystallization has gained significant attention due to its precise control over crystal formation in recent years; however, challenges remain in improving the efficiency and consistency of this process. Another emerging approach for crystallization is the use of microfluidic systems, where strategies such as solvent exchange, temperature modulation, and evaporation have been explored; however, achieving consistent and localized nucleation remains an active area of investigation. In this study, the probability of crystal enhancement through the integration of femtosecond laser-induced crystallization with microfluidic chip technology was investigated. A microfluidic device with a channel width of 3 mm, capable of continuous femtosecond laser pulse irradiation, was designed to control crystal number and size growth under a controlled flow rate. Sequentially, tunable crystal generation in the microfluidic chip was realized by irradiating the channel with femtosecond laser pulse supersaturated sodium chlorate (NaClO₃) solution as low threshold as σ = 0.002. The size and number of crystals could be tuned by the supersaturation and flow rate of the sample solution, the laser pulse energy, and the number of laser pulses.