Chinese researchers claim ‘breakthrough’ in deep UV laser technology

26 Mar 2025

Scientists at CAS develop compact, solid-state laser system that generates 193-nm coherent vortex beam.

Deep ultraviolet (DUV) lasers, known for their high photon energy and short wavelengths, are essential in various fields such as semiconductor lithography, high-resolution spectroscopy, precision material processing, and quantum technology.

These lasers offer increased coherence and reduced power consumption compared to excimer or gas discharge lasers, enabling the development of more compact systems.

As reported in Advanced Photonics Nexus, researchers from the Chinese Academy of Sciences have made a significant advancement by developing a compact, solid-state laser system capable of generating 193 nm coherent light.

Applications in lithography – and more

This wavelength is crucial for photolithography, a process used to etch intricate patterns onto silicon wafers. The new laser system operates at a repetition rate of 6 kHz and utilizes a homemade Yb:YAG crystal amplifier to produce a 1030 nm laser.

This laser is divided into two parts: one part undergoes fourth-harmonic generation to create a 258 nm laser with an output power of 1.2 W, while the other part pumps an optical parametric amplifier, generating a 1553-nm laser with a power of 700 mW.

These beams are then combined in cascaded LBO (lithium triborate, LiB₃O₅) crystals to produce the desired 193-nm laser, achieving an average power of 70 mW and a linewidth of less than 880 MHz.

The researchers also introduced a spiral phase plate to the 1553-nm beam before frequency mixing, resulting in the generation of a vortex beam carrying orbital angular momentum. This marks the first time a 193-nm vortex beam has been produced from a solid-state laser.

Such a beam holds promise for seeding hybrid ArF excimer lasers and could have significant applications in wafer processing, defect inspection, quantum communication, and optical micromanipulation.

This innovative laser system not only enhances the efficiency and precision of semiconductor lithography but also opens new avenues for advanced manufacturing techniques. The ability to generate a 193-nm vortex beam could lead to further breakthroughs in the field, potentially revolutionizing the way electronic devices are produced.

• This article was first published on spie.org.