Analysis of optical breakdown in water induced by 1 ns laser pulses

Uporaba laserjev ima pomembno vlogo v oftalmologiji. Za varno izvajanje posegov, ki temeljijo na fotodisrupciji, je potrebno dobro razumeti optični preboj v kapljevinah in spremljajoče fizikalne pojave. V kadici z destilirano vodo, ki predstavlja poenostavljen model očesa, smo z 1 ns laserskimi bliski diodno črpanega trdninskega laserja povzročali preboj. Z odklonsko sondo, PZT senzorjem in hitro kamero smo zaznavali kavitacijske mehurčke in udarne valove. Določili smo energijske pragove za preboj in maksimalne polmere mehurčkov pri različnih oddaljenostih mesta preboja od stene kadice. Opazovali smo dinamiko mehurčkov v bližini trdne meje in proste površine ter odboje udarnih valov. Ugotovili smo, da so uporabljene detekcijske metode ustrezne in zanesljive ter omogočajo ponovljive meritve.Lasers are an important instrument in ophthalmology. To provide safe photodisruption-based procedures, laser-induced breakdown in liquids and corresponding physical phenomena must be well understood. We used a diode-pumped solid-state laser with 1 ns pulses to induce breakdown in distilled water in a cell. Cavitation bubbles and shock waves were detected using beam-deflection probe, PZT sensor and high-speed camera. We determined threshold energies for laser-induced breakdown and maximal bubble radii at different distances between the breakdown volume and the cell wall. We analyzed bubble and shock wave dynamics near a solid boundary and a free surface. We established, that the used detection methods are suitable and reliable