Laser 3D Printing of Inorganic Free-Form Micro-Optics

A pilot study on laser 3D printing of inorganic free-form micro-optics is experimentally validated. Ultrafast laser direct-write (LDW) nanolithography is employed for structuring hybrid organic-inorganic material SZ2080TM followed by high-temperature calcination post-processing. The combination allows the production of 3D architectures and the heat-treatment results in converting the material to inorganic substances. The produced miniature optical elements are characterized and their optical performance is demonstrated. Finally, the concept is validated for manufacturing compound optical components such as stacked lenses. This is an opening for new directions and applications of laser-made micro-optics under harsh conditions such as high intensity radiation, temperature, acidic environment, pressure variations, which include open space, astrophotonics, and remote sensing.

Parameter Optimization of Laser Direct-Write Patterning on Indium Tin Oxide/Polycarbonate Thin Films Using Multi-Performance Characteristics Analysis

Indium tin oxide (ITO) thin films on polycarbonate (PC) substrates were patterned using the laser direct-write (LDW) technique to form an isolation line. The effect of the LDW parameters (power, pulse repetition rate, and defocusing distance) on the isolation line width, depth and roughness of the PC within the line was investigated. Additionally, the Taguchi method of experimental design was applied to determine the optimal parameters of LDW. Results showed that increasing the power led to an increase in the isolation line width and decrease in the surface roughness of the PC within the line. The increase in the pulse repetition rate and defocusing distance caused a decrease in the isolation line width. The optimal parameters were found to be A2B3C3, consisting of power of 5 W, pulse repetition rate of 100 kHz, and defocusing distance of +3 mm. Under these parameters, we obtained an isolation line width of 48.4 μm, and a surface roughness of Ra 38 nm of the PC within the isolation line. We confirmed that the ITO films separated by the isolation lines attained electrical isolation.

Acoustically-shaped laser: a machining tool for Industry 4.0

The high versatility of laser direct-write (LDW) systems offers remarkable opportunities for Industry 4.0. However, the inherent serial nature of LDW systems can seriously constrain manufacturing throughput and, consequently, the industrial scalability of this technology. Here we present a method to parallelise LDWs by using acoustically shaped laser light. We use an acousto-optofluidic (AOF) cavity to generate acoustic waves in a liquid, causing periodic modulations of its refractive index. Such an acoustically controlled optical medium diffracts the incident laser beam into multiple beamlets that, operating in parallel, result in enhanced processing throughput. In addition, the beamlets can interfere mutually, generating an intensity pattern suitable for processing an entire area with a single irradiation. By controlling the amplitude, frequency, and phase of the acoustic waves, customised patterns can be directly engraved into different materials (silicon, chromium, and epoxy) of industrial interest. The integration of the AOF technology into an LDW system, connected to a wired-network, results into a cyber-physical system (CPS) for advanced and high-throughput laser manufacturing. A proof of concept for the computational ability of the CPS is given by monitoring the fidelity between a physical laser-ablated pattern and its digital avatar. As our results demonstrate, the AOF technology can broaden the usage of lasers as machine tools for industry 4.0