Investigation of UV picosecond laser ablation of polymers

Abstract

UV picosecond laser pulses have been shown to be able to etch clean holes in polymers. This process has numerous applications in processing polymers. We present the results obtained by the investigation of the laser ablation process with picosecond pulses in 19 different organic materials. Micro-drilling and cutting of polymers were performed by the 355 and 266 nm radiation. The ablation rate versus laser fluence was investigated. Polymers showed the logarithmic ablation rate versus the laser fluence proving a well known Beer's model of laser ablation. Two ablation thresholds were observed in most of the polymers. One of them was below 1 J/cm 2 with a low material removal rate. Another threshold was spread in the range of 3 -30 J/cm 2 and a rapid increase in the ablation rate was found above it.The processing of polymers was tested in fabrication of cavities relevant to different micro-devices. Combined cavities for the ink-jet printer head and micro-fluidic set were formed by laser etching. UV laser radiation with the picosecond pulse duration can be useful in manufacturing micro-systems for diverse technical applications.

Numerical simulation of ultraviolet picosecond Ce:LiCAF laser emission by optimized resonator transients

“…22) An important advantage of having ultrashort UV pulses, especially in micromachining is that the peak power is high therefore limiting material modification to the area around the laser focus. 23) Ultrashort pulses also permit outstanding temporal resolutions for pump-probe experiments. 24) Initial calculations have to be done to investigate the influence of optical parameters, such as pumping energy, Q-value and cavity length on the output energy and pulse duration of a Ce:LiCAF UV laser, and hence optimize laser oscillator design.…”

Analytical Study on Pulsed-Laser Processing for Acrylonitrile Butadiene Styrene/ PolyVinyl Chloride

“…19, the energy balance at decomposition interface, boundary conditions and initial condition. Table 1 and Table 2 , respectively, list material properties [20] that are used in the theoretical calculation for this model and the parameters that are used in experiments [19] and calculations. While detailed information about the content of PVC in ABS is not provided in [19], the input values of material properties of ABS/PVC matching the experimental data in this simulation are between material properties of ABS and PVC.…”

“…Most plastics tend to decompose below the evaporation temperature and long chains of molecules are decomposed into fragments before they are removed by laser from bulk material. The ablated depth per pulse mainly depends on the amount of broken bonds in polymeric chain [18,19]. The laser heating spot inflates rapidly.…”

Design and Preliminary Validation of a Rapid Automated Biodosimetry Tool for High Throughput Radiological Triage

“…The output power of the laser beam is 1.1W with 355nm wavelength, 20kHz pulse repetition frequency and 40μm of the effective spot size, thus the laser fluence is 4.377 J/cm 2 . As to PVC absorption rate in [7], absorbed pulse energy of 266nm wavelengths is 18.33μJ, and the laser fluence at the focal plane becomes 1.46J/cm 2 . Since the PVC ablation rate is 2.5μm/pulse [7], the thickness of the capillary is 0.5mm, so there should be at least 200 laser pulses of 0.01s duration to cut off the capillary.…”

“…As to PVC absorption rate in [7], absorbed pulse energy of 266nm wavelengths is 18.33μJ, and the laser fluence at the focal plane becomes 1.46J/cm 2 . Since the PVC ablation rate is 2.5μm/pulse [7], the thickness of the capillary is 0.5mm, so there should be at least 200 laser pulses of 0.01s duration to cut off the capillary. The corresponding rotation speed of the capillary gripper is 35.7rpm.…”