Micro-hole drilling in thin films with cw low power lasers

Abstract

In this work, we perform drilling of micro-holes and micropatterning in indium tin oxide (ITO) and titanium thin films. In ITO films the drilling is performed by thermocavitation only; meanwhile in titanium two competing processes are identified: (i) laser-induced sublimation producing high-quality micro-holes comparable to those produced with femtosecond pulses but at a reduced cost and (ii) erosion by thermocavitation which tend to degrade the quality of the micro-holes. The micro-holes can be employed as micrometer light sources for use in pointdiffraction interferometers or spatial filters; in addition, micron-sized resolution patterning can be performed.

Optic cavitation with CW lasers: A review

“…For many applications such as surface damage 33 and ultrasound generation, 7 it is desirable to obtain the largest bubble possible. As mentioned earlier, this can be achieved by increasing the spot size in order to increase the superheated volume.…”

Simple optical system for manufacturing point diffraction interferometer plates in titanium films using a low intensity CW laser beam

“…A low power laser with wavelength of 532.8 nm is used but, since we work in the visible region, the alignment of the optical system is easier than the case of infrared laser, as previously reported. 3) The diameters of the obtained pinholes can be from 1 to 8 m. To our knowledge, the application of laser ablation for fabricating PDI plates has not been reported. In the next section we present the theory that helps us to understand the application of our proposed technique; then in Sect.…”

“…Ramirez-San-Juan et al have illustrated the possibility of making pinholes in the range of 600 nm to 1.2 m of diameter, by means of the sublimation of a titanium film of 65 nm of thickness, using CW low power infrared laser. 3) On the other hand, point diffraction interferometer (PDI) has been applied in many fields of optics, going from optical testing to optical tomography. [4][5][6][7][8] The nucleus of this interferometer is a glass plate covered with a thin film wherein a pinhole has been made.…”

Numerical Calculation of the Shear Stress Generated by the Flow Field Induced by an Oscillating Bubble Between Two Solid Boundaries

“…Using such CW lasers to generate cavitation bubbles in a controlled way offers an alternative to fabricate microstructures onto thin solid films between one and two orders of magnitude less expensive, compared to bubbles produced with high intensity pulsed lasers [17]. For these bubbles to interact with the thin film, it is required to induce them within an absorbing solution volume such that its height is comparable with the bubble size.…”