Laser ablation (LA), which employs a pulsed laser to remove materials from a substrate for generating micro-/nanostructures, has tremendous applications in the fabrication of metals, ceramics, glasses and polymers. It has become a noteworthy approach for achieving various functional structures in engineering, chemistry, biology, medicine and other fields. Polymers are one such class of materials; they can be melted and vaporized at high temperature during the ablation process. A number of polymers have been researched as candidate substrates in LA, and many different structures and patterns have been realized by this method. The current states of research and progress are reviewed from basic concepts to optimal parameters, polymer types and applications. The significance of this paper is to provide a basis for follow-up research that leads to the development of superior materials and high-quality production through LA. In this review, we first introduce the basic concept of LA, including mechanism, laser types (millisecond, microsecond, nanosecond, picosecond and femtosecond) and influential parameters (wavelength, repetition rate, fluence and pulse duration). Then, we focus on several commonly used polymer materials and compare them in detail, including the effects of polymer properties, laser parameters and feature designs. Finally, we summarize the applications of various structures fabricated by LA in a variety of areas along with a perspective of the challenges in this research area. Overall, a thorough review of LA of several polymers is presented, which could pave the way for characterization of future novel materials.

No abstract

Microdrilling based on laser ablation has been widely applied for manufacturing micro-/nanofeatures on different materials as a noncontact thermal removal approach. It has the advantages of high aspect ratio manufacturing capability and reduced surface damage. However, laser ablation is a complicated process that is challenging to model. In this paper, a standardized modeling procedure was demonstrated to predict the area and depth of laser ablation based on experimental study and simulation validation. A case study was conducted where microdrilling of high-density polyethylene (HDPE) was investigated using a 1064 nm nanosecond pulsed laser. Blind microholes were fabricated on the HDPE samples by ablating under different laser powers and numbers of pulses. Gain factors were defined and determined by the experimental data. A quantitative area-depth approximation model was formulated based on the gain factors. A comparison of the measured and the simulated results of microholes presented average 96.5% accuracy for the area and 85.7% for the depth. This research provided a simple but effective approach to predict dimensions of microholes on various substrates using laser ablation under different laser powers and the numbers of pulses, which could pave the way for development and modeling of laser ablation on polymers.

Laser ablation has been widely used for material removal on different types of substrates. Accurate feature profile fabrication with minimum damage to the surrounding material requires precise control of the laser and material parameters. One approach to achieve this is by establishing a simulation model to help process control and optimization. However, laser ablation is a complex process that is difficult to model. In this paper, numerical simulation models have been established to identify the temperature at the ablation surface and the ablation depth profile evolution over time. The ablation has been modeled using the heat transfer in solids module in COMSOL Multiphysics with the manual material definition of high-density polyethylene (HDPE). The laser beam is modeled as a continuous heat source by utilizing a ramp function. Information for establishing a pulsed laser system has been provided. Results are provided for the surface temperature and depth profile evolution for various time steps. Results of the simulation of laser ablation of HDPE sample using a 50W laser using both the models were presented. The next step of our work is to validate the simulation results by comparing it against experimental data. This will render these models to have the potential to be able to predict the ablation crater profile with higher accuracy. This model will pave the way for a better understanding of the ablation threshold conditions and identifying the ablation initiation in any material, given the material properties are known.