To begin, choose the target material and surrounding liquid. Perform ultrasonic cleaning of the target surface using acetone for 15 minutes to remove organic materials, such as oils, greases, and waxes. Subject the surface to ultrasonic cleaning with ethanol for another 15 minutes to remove polar contaminants like salts and sugars.
Then clean the surface with deionized water using ultrasonic cleaning for 15 minutes to remove any residual solvents or contaminants from the sample's surface. Measure the weight of the sample before ablation, then perform a laser ablation experiment on the sample. Measure the weight of the sample again after the ablation experiment.
Estimate the amount of material removed during the experiment by comparing the weight of the sample before and after ablation. Next, adjust the input laser power to approximately 150 milliwatts for picosecond laser ablation of the silver target. Combine a polarizer and a half-wave plate to adjust the laser pulse energy.
Focus the laser beam onto the sample using a focusing lens to ablate the material surface. Manually adjust the laser's focus on the sample using a translation stage in the Z direction while observing the bright plasma produced and the cracking sound emanating. Next, use focusing optics for focusing the laser beam onto the sample depending on achieving different ablation depths and improving control over nanoparticles and nano structures synthesis.
Position the sample on the XY stage connected to an ESP controller ensuring it moves perpendicular to the laser propagation direction. Adjust the scan speed and laser processing area to optimize the number of laser pulses interacting with the sample. During the laser ablation process, perform laser patterning while scanning the sample to achieve the desired dimensions and prevent single point ablation.
Next, for laser ablation in liquid, conduct a laser ablation experiment. Monitor laser power and other settings to maintain consistency. Continuously observe the target material during the experiment ensuring the laser beam stays focused on the desired area.
The absorption spectra of silver colloidal nanoparticles revealed that surface plasmin resonance peaks were observed at 420, 394, and 403 nanometers for different laser wavelengths. The normalized absorbance spectra of silver gold alloy nanoparticles with different compositions revealed a surface plasmin resonance peak shift from 410 to 519 nanometers as the gold percentage increased from zero to 100.
