A significant breakthrough in laser technology has been achieved by a compact solid-state laser system generating coherent light at 193 nanometers with the novel capability of producing vortex beams carrying orbital angular momentum.
This innovation is particularly important for semiconductor lithography, where deep ultraviolet (DUV) light at 193 nm has become essential for high-resolution patterning of silicon wafers. The researchers’ system offers advantages over traditional excimer lasers by achieving higher coherence in a more compact form factor.
The laser system operates at a 6 kHz repetition rate using a custom Yb crystal amplifier that produces a 1030-nm base beam. This beam is divided: one portion undergoes fourth-harmonic generation to create a 258-nm beam (1.2W), while the remainder powers an optical parametric amplifier generating a 1553-nm beam (700mW). These beams are then mixed in cascaded lithium triborate crystals to yield the 193-nm output with 70mW average power and a narrow linewidth under 880 MHz.
What makes this development particularly groundbreaking is the introduction of a spiral phase plate to the 1553-nm beam, creating the first-ever demonstration of a 193-nm vortex beam with orbital angular momentum from a solid-state laser. This achievement has significant implications for seeding hybrid ArF excimer lasers, improving wafer processing, and advancing defect inspection techniques.
The paper, published in Advanced Photonics Nexus, outlines how this system overcomes previous limitations in generating high-power 193-nm light. Earlier approaches using KBBF crystals faced scaling challenges, while erbium-doped fiber amplifiers struggled with nonlinear effects at high powers. The researchers’ optical parametric amplifier approach provides better scalability and wavelength flexibility.
Their innovative configuration opens new possibilities for semiconductor manufacturing and quantum applications. The vortex beam capability may revolutionize optical micromanipulation and quantum communication by leveraging the orbital angular momentum properties of light at this technically challenging wavelength.
This development represents not just an incremental improvement but a fundamental advance in DUV laser technology that could transform multiple high-precision manufacturing and scientific fields.
Reference: “Compact narrow-linewidth solid-state 193-nm pulsed laser source utilizing an optical parametric amplifier and its vortex beam generation” by Zhitao Zhang, Xiaobo Heng, Junwu Wang, Sheng Chen, Xiaojie Wang, Chen Tong, Zheng Li and Hongwen Xuan, 9 March 2025, Advanced Photonics Nexus. DOI: 10.1117/1.APN.4.2.026011
