For the first time, researchers in Sweden 3D printed silica glass micro-optics on the tips of optic fibers. The advance could enable faster internet and improved connec­tivity, as well as innovations like smaller sensors and imaging systems. The scientists at KTH Royal Institute of Techno­logy in Stockholm say inte­grating silica glass optical devices with optical fibers enables multiple innovations, including more sensitive remote sensors for environment and healthcare. The printing techniques they report also could prove valuable in production of pharma­ceuticals and chemicals.

Kristinn Gylfason says the method overcomes longstanding limitations in structuring optical fiber tips with silica glass, which he says often require high-tempera­ture treatments that compromise the integrity of temperature-sensitive fiber coatings. In contrast to other methods, the process begins with a base material that doesn't contain carbon. That means high temperatures are not needed to drive out carbon in order to make the glass structure trans­parent. His colleague Lee-Lun Lai says the researchers printed a silica glass sensor that proved more resilient than a standard plastic-based sensor after multiple measure­ments.

“We demonstrated a glass refractive index sensor integrated onto the fiber tip that allowed us to measure the concen­tration of organic solvents. This measurement is challenging for polymer-based sensors due to the corrosiveness of the solvents,” Lai says. “These structures are so small you could fit 1,000 of them on the surface of a grain of sand, which is about the size of sensors being used today,” says Po-Han Huang.

The researchers also demonstrated a technique for printing nanogratings, ultra-small patterns etched onto surfaces at the nanometer scale. These are used to manipulate light in precise ways and have potential applications in quantum communi­cation. Gylfason says the ability to 3D print arbitrary glass structures directly on fiber tip opens new frontiers in photonics. “By bridging the gap between 3D printing and photonics, the implications of this research are far-reaching, with potential applications in micro­fluidic devices, MEMS accelerometers and fiber-inte­grated quantum emitters,” he says. (Source: KTH)

Reference: L.-L. Lai et al.: 3D Printing of Glass Micro-Optics with Subwavelength Features on Optical Fiber Tips, ACS Nano 18, 10788 (2024); DOI: 10.1021/acsnano.3c11030

Link: Division of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden