Continuous-wave second-harmonic generation in the far-UVC pumped by a blue laser diode

Area of Science:

• Optics and Photonics
• Materials Science
• Laser Technology

Background:

• Far-ultraviolet C (far-UVC) light (200-230 nm) offers pathogen inactivation with human safety.
• Existing far-UVC sources are often bulky or inefficient, limiting widespread application.
• Compact, solid-state sources are needed for practical disinfection and deep-UV applications.

Purpose of the Study:

• To develop a compact, solid-state far-UVC laser source.
• To achieve efficient second-harmonic generation (SHG) for far-UVC production.
• To explore heterogeneous integration for optimized performance.

Main Methods:

• Utilized a low-cost blue laser diode as a pump source.
• Employed second-harmonic generation (SHG) within a nanophotonic silicon nitride (SiN) waveguide.
• Achieved Cherenkov phase-matching at the interface with a beta barium borate (BBO) nonlinear crystal.
• Investigated waveguide dimensions and pump power for optimization.

Main Results:

• Successfully generated far-UVC light using a compact solid-state laser.
• Demonstrated efficient Cherenkov phase-matching via heterogeneous integration.
• Analyzed dependencies of emission angle, conversion efficiency, and output power.
• Confirmed feasibility for mass production in a compact form factor.

Conclusions:

• The developed solid-state far-UVC laser source is a viable technology.
• Significant potential for human-safe disinfection applications.
• Promising for free-space communication and deep-UV Raman spectroscopy.