# Fabrication of Smart Materials Using Laser Processing: Analysis and Prospects
## 2 Laser Modification for Smart Materials
These microstructures range from hypoeutectic with a low boride content to mixed borides, aligning with the Fe-B phase diagram (Figure 3). The surface laser alloying process involved a fiber laser machine with a wavelength of 1070 nm. Significant processing parameters included a laser power of 300 W, a laser spot diameter of 1 mm, and a variable laser operating speed ranging between 500 and 1500 mm/min. This laser bording method significantly improves wear resistance in martensitic aging steels, enhancing it by up to 7.5 fold. Figure 1: Schematic of the laser hardening process illustrating the beam power distribution in specific planes for experimental studies [62]. Figure 2: The microstructure of the cross-section of the laser-hardened AISI 420 steel [63]. Laser doping introduces specific elements or dopants into the material's surface layer, modifying its electronic properties and enhancing semiconductor characteristics [68]. In such cases, subsequent laser annealing can achieve high crystallinity comparable to conventional thermal furnace annealing, but with significantly lower heat input or thermal budget [69]. Laser modification can also activate functional groups on the material's surface [70; 71], allowing the creation of smart materials with functional properties, such as chemical sensing for the destruction or inhibition of microorganisms [72]. Laser surface modification can be used to create biocompatible materials for medical implants, with controlled surface properties that promote tissue integration [73; 74; 75]. Laser-modified surfaces can improve the adhesion of electronic components or create specialized surfaces for MEMS and sensors [76]. The study in [77] introduced a novel technology for precision manufacturing of quartz resonators for MEMS. This approach relies on laser-induced chemical etching of quartz. The key processing steps involve femtosecond UV laser treatment of alpha quartz plates with Z-cuts, coated with Cr-Au, followed by wet etching. The laser chemical etching process utilized a laser system with pulse widths ranging from 270 fs to 10 ps. It generated pulses with a wavelength of 343 nm, reaching a maximum energy of 40 uJ at a frequency of 175 kHz. The laser output was scanned using low group delay dispersive mirrors and a Newson galvanometer scanner with an F-Theta lens. A visual comparison of etched quartz surfaces with and without prior irradiation is presented in Figure 4. This fabrication method, employing femtosecond laser-induced chemical etching, enables the attainment of superior surface quality using the same wet etching parameters. Laser-induced surface structures have diverse applications, also in antireflective coatings and high-transparency glasses. For the creation of antireflective coatings, femtosecond laser pulses, with a central wavelength of 1045 nm, a pulse width of 700 fs, and a frequency of 100 kHz were utilized [78]. In the production of high-transparency glasses, a Yb:KGW laser amplifier was employed to generate a linearly polarized femtosecond laser with a central wavelength of 1030 nm, a frequency of 10 kHz, and a pulse duration of 216 fs. The laser beam was focused by a convex lens [79].