In the realm of advanced manufacturing, a groundbreaking technique has emerged that could revolutionize the way we fabricate intricate microstructures, with significant implications for the energy sector. Researchers, led by Tianshi Lu from the Tsinghua Shenzhen International Graduate School at Tsinghua University, have developed a novel method called contact-interference assembly hybrid lithography. This innovation addresses a longstanding challenge in the fabrication of micro-polarization arrays, which are crucial components in polarization imaging systems used in remote sensing and other advanced applications.
Polarization imaging leverages the properties of light to capture information that traditional imaging systems miss. By applying subwavelength metal grating arrays, these systems can enhance remote sensing capabilities, offering clearer and more detailed images. However, the dual size-scale features of these arrays—periodic subwavelength grating structures with feature sizes of hundreds of nanometers and pixel quadrants with dimensions on the order of tens of micrometers—have made their efficient fabrication a significant hurdle.
Lu and his team have tackled this issue head-on. Their method involves using interference fringes generated by two coherent laser beams to create fine grating structures. A specially designed, flexible mask segments the interference wavefront, producing the grating structures in each quadrant of the array unit in a single-cycle process. This approach ensures sub-micron alignment accuracy and suppresses the adverse effects of the gap between the mask and the substrate by smoothing out the refractive index.
The results are impressive. The team constructed a double-layer metal grating with a 20 mm × 20 mm four-quadrant array, achieving a period of 950 nm and a unit size of 15 μm × 15 μm. The total exposure time was a mere 180 seconds, representing a 3–4 orders of magnitude reduction in fabrication time compared to traditional electron beam lithography. The quadrant micro-polarizer exhibited a polarization extinction ratio of over 20 dB and an equivalent transmittance of approximately 50%, demonstrating the feasibility of the proposed method for scalable fabrication.
“This breakthrough opens up new possibilities for the energy sector,” says Lu. “By enabling the efficient production of high-quality micro-polarization arrays, we can enhance the capabilities of remote sensing systems used in energy exploration and monitoring. This could lead to more accurate and efficient energy resource management, ultimately benefiting both the environment and the economy.”
The implications of this research extend beyond the energy sector. The ability to fabricate complex microstructures quickly and accurately has applications in various fields, including telecommunications, medical imaging, and advanced manufacturing. As the demand for high-precision components grows, the contact-interference assembly hybrid lithography method could become a cornerstone of modern manufacturing processes.
Published in the ‘International Journal of Extreme Manufacturing’ (translated to English as “International Journal of Extreme Manufacturing”), this research marks a significant step forward in the field of lithography. The journal, known for its cutting-edge contributions to advanced manufacturing technologies, provides a platform for researchers to share their innovations with a global audience.
As the world continues to push the boundaries of what is possible, the work of Lu and his team serves as a testament to the power of innovation and the potential for transformative change. By addressing a critical challenge in the fabrication of microstructures, they have paved the way for advancements that could shape the future of technology and industry.