Deep Ultraviolet Laser Breakthrough: Compact Solid-State System Advances Semiconductor Lithography And Quantum Communication

As reported in Advanced Photonics Nexus, researchers from the Chinese Academy of Sciences have developed a compact solid-state laser system capable of generating 193-nm coherent light. This advancement involves a Yb:YAG crystal amplifier operating at a 6 kHz repetition rate, producing a 1030-nm laser that is split into two beams for further processing. One beam undergoes fourth-harmonic generation to create a 258-nm laser with 1.2 watts of output power, while the other pumps an optical parametric amplifier to generate a 1553-nm laser at 700 milliwatts.

These beams are combined in cascaded LBO crystals to produce the desired 193-nm laser, achieving an average power of 70 milliwatts and a linewidth under 880 MHz. The researchers introduced a spiral phase plate to the 1553-nm beam, resulting in the first solid-state generation of a 193-nm vortex beam with orbital angular momentum. This innovation holds potential for applications in photolithography, wafer processing, defect inspection, quantum communication, and optical micromanipulation.

Deep Ultraviolet Lasers: Essential Technology for Modern Applications

Deep ultraviolet (DUV) lasers are characterized by their high photon energy and short wavelengths, making them indispensable in various fields. These include semiconductor lithography, where precise etching of patterns onto silicon wafers is essential; high-resolution spectroscopy for detailed analysis; precision material processing; and quantum technology advancements. Compared to older technologies like excimer or gas discharge lasers, DUV lasers offer higher coherence and lower power consumption, enabling more compact systems.

A recent advancement in this field comes from researchers at the Chinese Academy of Sciences, who developed a compact solid-state laser system capable of generating 193-nm coherent light. This wavelength is critical for photolithography. The system operates at a 6 kHz repetition rate and utilizes a Yb:YAG crystal amplifier to produce a 1030-nm laser. This laser is split into two components: one undergoes fourth-harmonic generation to create a 258-nm beam with 1.2W output, while the other pumps an optical parametric amplifier, generating a 1553-nm beam at 700 mW. These beams are combined in lithium triborate (LBO) crystals to achieve the desired 193-nm laser, resulting in an average power of 70 mW and a linewidth under 880 MHz.

The researchers introduced a spiral phase plate to generate a vortex beam with orbital angular momentum at 193 nm, marking the first such achievement from a solid-state laser. This innovation holds potential for seeding hybrid ArF excimer lasers and has promising applications in wafer processing, defect inspection, quantum communication, and optical micromanipulation. These developments underscore the versatility and growing importance of DUV lasers in modern technological advancements.

The system achieves an average power of 70 mW at 193 nm with a linewidth under 880 MHz, demonstrating high efficiency and stability. The ability to generate vortex beams adds new functionality, enabling applications that require precise control of light’s angular momentum. This capability could improve the performance of existing lithography tools while reducing operational complexity and cost.

In semiconductor manufacturing, 193-nm lasers can enhance wafer processing by enabling more precise material removal or surface modification. The orbital angular momentum inherent in vortex beams allows for improved control over light-matter interactions, potentially reducing defects and increasing yield.

Defect inspection systems could benefit from the high spatial resolution provided by 193-nm lasers, particularly in identifying submicron-scale imperfections on optoelectronic devices or integrated circuits. The ability to generate structured light at this wavelength may also improve sensitivity in detecting surface irregularities or material inconsistencies.

In quantum communication, the use of vortex beams at 193 nm could advance research into entangled photon states and free-space optical links. The short wavelength offers advantages for atmospheric transmission and high-bandwidth data transfer, while the angular momentum properties provide additional degrees of freedom for encoding information.

Optical micromanipulation applications, such as particle trapping or manipulation, can leverage the unique beam characteristics to achieve higher precision and efficiency. The 193-nm wavelength is particularly suited for interacting with dielectric particles or biological samples, offering potential advancements in lab-on-a-chip technologies and microfluidic systems.

The ability to seed hybrid ArF excimer lasers with this compact solid-state system introduces new possibilities for laser-based manufacturing and research. This capability could improve the performance of existing lithography tools while reducing operational complexity and cost.