One application that 3D printing technology stands to benefit greatly, but still needs a heft amount of research in, is the manufacturing of optics. While companies such as LUXeXcel have been working to replace injection molded optics with their proprietary printing process, and researchers from the University of Sydney are successfully 3D print fiber optics, it’s evident that 3D printing technology is on the brink of revolutionizing the way optics are produced. Though a number of these innovations seem like a pretty big deal, sometimes it’s the (literally) smaller breakthroughs that really shake things up. One group of German researchers, from the University of Stuttgart, have discovered that they could produce micron-scale optics on a 3D printer created with help from Nanoscribe, which is a spin-off from the Karlsrhue Insitute of Technology (KIT).
The method researched by the team, which is called femtosecond laser writing, can be utilized to 3D print integrated optics at a micron-scale, which could potentially lead to most efficient miniaturized optical instruments. The laser writing technique works by emitting short laser pulses of light to very precise areas, hardening light-sensitive material into a 3D structure. Although this type of technique has been used in a number of research labs in the past, environmental conditions and variances have prevented other researcher teams from 3D printing micro-optics in high quality on a consistent basis. In order to alleviate this issue, the German research team utilized a two-photon 3D laser lithography system, which was specifically designed to write nanometre-sized structures.
“Although femtosecond laser writing has been demonstrated in the lab, we have shown that it can be used to make high performance micro-optics in a manner that is highly repeatable and reliable,” said the University of Stuttgart’s Harald Giessen, who led the research team. “We believe our approach can be scaled up for volume manufacturing and used to directly print almost any type of optical element on a tiny scale, opening up a new era of integrated micro- and nano-optics.”
By achieving sub-micron accuracy with the laser writing process, the University of Stuttgart research team were able to place phase masks on the end of the optical fiber, offering a way to shape the light coming out of the end of a optical fibre without the traditional need for large and bulky lenses. The team experimented with numerous approaches for printing these phase masks, such as layer by layer (from the bottom up) and ring by ring (starting from the center), both of which proved successful in creating high quality optics. By replacing traditionally larger optical lenses with these micro-sized alternatives, this research has the potentially to enhance numerous applications, such as illumination in smaller endoscopes and optical trapping particles or cells. Currently, the team is attempting to use the laser writing system to create a phase mask that will shape the output from optical fiber into a twisted light, which can potentially help with photon entanglement and more. All in all, the German research team have further proven the possibilities of 3D printing with optical lenses, and also proved that sometimes the smaller sized innovations can have the biggest impact.