An ultraviolet tunable light source (UV-TLS) is a valuable tool in studying the effectiveness of virus inactivation using UV radiation. UV-TLS can verify effective inactivation UV dosages at different wavelengths to help establish industrial UV safety standards and calibrate UV radiation sources.

We developed a high throughput UV-TLS to support research into methods of inactivating coronavirus, including the virus that causes the COVID-19 disease. The light source is powered by a laser-driven light source (LDLS™) with high UV wavelength brightness, superior stability, and a 10,000-hour lifetime. The UV-TLS covers the wavelength range from 200 nm to 770 nm and has a fiber-coupled output. Advanced design features include: (1) all reflective optics for aberrationfree light coupling; (2) a high-efficiency UV grating blazed at 250 nm; (3) fiber-coupled output with a 600 μm core diameter deep-UV fiber for application flexibility.

Measured data shows that the UV-TLS achieved an in-band flux of 0.98 mW with an averaged FWHM of 4.3 nm in the 200 nm to 400 nm range, using the 600 μm fiber. The averaged in-band flux reaches 2.9 mW for free-space output with an averaged FWHM of 7.2 nm.

Advantages of the newly developed UV-TLS are relatively higher in-band flux, UV light output at any wavelength from 200 nm to 400 nm, and the flexibility of a fiber light delivery. The bandwidth of UV output flux can be adjusted by selecting different monochromator slit sizes.