This device can generate deep-UV light with a very narrow wavelength range that is safe for humans but lethal for germs.

This device can generate deep-UV light with a very narrow wavelength range that is safe for humans but lethal for germs. The researchers have overcome these challenges by using a process called ‘second harmonic generation,’ which relies on the fact that the frequency of a photon, or particle of light, is proportional to its energy.

By using a specially designed waveguide that can control the orientation of the aluminum-nitride crystal, the researchers were able to merge two photons with half the energy into one photon with twice the energy, and thus, twice the frequency. This way, they could produce deep-UV light with a very narrow wavelength range that is safe for humans but lethal for germs.

Wavelength conversion device using polarity inverted AlN structure. CREDIT: HIROTO HONDA Hiroto Honda, the study's lead author, explains that their novel approach to generating deep-UV light incorporates methods from semiconductor manufacturing. This enables accurate manipulation of the aluminum-nitride crystal's orientation, a feat that was challenging to accomplish previously.

Aluminum-nitride bilayer channel