Femtosecond laser two-photon polymerization nanolithography

The above-mentioned laser nano-processing technology is used to form 2D large-area nanostructures on the surface of the sample. Femtosecond laser two-photon-polymerization (2PP) nanolithography is a promising method to form arbitrarily large-area 3D nanostructures. When the femtosecond laser beam is focused on the photosensitive material, the polymerization process is activated by two-photon nonlinear absorption. A computer-controlled femtosecond laser beam scans the shape to form a 3D structure of any design. After laser scanning, the unirradiated photosensitive material is washed away. Due to the light irradiation threshold effect and nonlinear light absorption properties of the process, flexible control of laser pulse energy and pulse repetition rate to form functional 3D nanostructures can form super-resolution beyond the optical diffraction limit (minimum 60 nm). Laser microlens array lithography Due to the limitation of the size of the microsphere array formed on the surface of the sample, the nanostructures formed by the microsphere array technology-assisted laser nanoprocessing are generally very small, with an area less than 1 square centimeter. At the same time, defects are generated during the formation of microsphere arrays by self-alignment or spin coating. Laser microlens array (MLA) lithography processing is easier and more suitable for large-scale production of nanostructures for industrial applications. The photoresist coated sample is mounted on a 7-axis nano-stage and positioned on the focal plane of the MLA. By controlling the movement of the stage and turning on/off the laser pulse, arbitrary patterns can be formed on the photoresist layer by laser irradiation. Laser MLA lithography has the unique advantage of forming large-area arbitrary nanostructures at high speed in parallel mode. This method can also be used to form functional nanostructures on various substrate surfaces, such as split ring resonator (SRR) arrays on flexible polymer films, which can be rolled up and used as 3D metamaterial pipelines for ultra-sensitive applications. . The development prospects of laser nano-processing Extreme ultraviolet (EUV) nano-lithography and laser cooling are two highly potential ways to meet the requirements of the sub-20 nm nano-processing industry. Although almost all materials have strong absorption of EUV light, EUV optical equipment and photomasks are very expensive and easily damaged. The successful development of direct-write multi-beam maskless EUV nanolithography technology is a feasible solution to overcome this technical challenge. In addition, laser cooling can control the deposition of atoms on the surface of the substrate while the atoms are passing through, and the standing waves of the laser beam interference configuration are 'focused to achieve a body size as low as sub-10 nm. For more information, please click on related reading: Microsphere Array Assisted laser nano processing