Optical cavitation in non-absorbent solutions using a continuous-wave laser via optical fiber

Current State of Research on the Mechanism of Cavitation Effects in the Treatment of Liquid Petroleum Products—Review and Proposals for Further Research

“…Optical cavitation and particle cavitation are not used on an industrial scale but are used mainly for experimental studies to study the shapes of cavitation bubbles. Optical cavitation can be created either by short laser pulses focused on a solution with a low absorption coefficient or by using a continuous laser [23][24][25]. Cavitation created by continuous lasers in the dye-doped binary solutions was first described by Rastopopov and Sukhodolsky back in 1990 [23,24].…”

Non-thermal, energy efficient hydrodynamic cavitation for food processing, process intensification and extraction of natural bioactives: A review

“…The initial energy in the pulse is received by laser-produced plasma, then transformed to light, heat, and mechanical energy, which are observed in the shock wave and bubble [11] . In this case, the light intensity at the point is so high that nonlinear absorption or snow slide ionization creates plasma, which can rapidly heat up owing to the laser, resulting in abrupt water vaporization and forming vapor bubbles [12] . The cavitation bubble expands to its maximum size before collapsing to restart the process.…”

Shorts pulse generation by optical cavitation using absorbent and non-absorbent solutions

“…1. 𝐴𝑔𝑁𝑃𝑠 and 𝐶𝑢(𝑁𝑂 3 ) 2 were immobilized on the surface of a final section of a multimode optical fiber (Thorlabs FG105LVA, 105/125 µm) using the photodeposition technique, previously reported in references [14][15][16]. The optical power loss due to the absorption of 𝐴𝑔𝑁𝑃𝑠 was approximately 2.6 dB, while the loss caused by the 𝐶𝑢 (𝑁𝑂 3 ) 2 nanoparticles was 3.1 dB, resulting in an optical loss of 5.7 dB in the fiber output.…”

“…A characteristic of the optical cavitation phenomenon is its repetitive nature, where the cavitation frequency directly depends on the power of the laser [18] and the number of nanoparticles in the tip of the optical fiber [16]. When the tip of the optical fiber is placed in the solution, and there is no generation of microbubbles, the amount of light reflected toward the fiber is minimal.…”

“…This facilitates more stable nucleation times and rapid reaching of the critical point of the solution. The laser light transmitted through the optical fiber is strongly absorbed by the 𝐴𝑔𝑁𝑃𝑠 and the surrounding liquid medium, leading to a rapid temperature increase around the tip of the optical fiber, reaching the spinodal limit of ethanol (⁓187 °C) [16]. At this temperature, an explosive phase transition occurs, causing the generation of a microbubble, which grows until it reaches its maximum radius and then collapses.…”