Figure 7
From: Continuous-wave second-harmonic generation in the far-UVC pumped by a blue laser diode
(a), Tuning the single-frequency pump laser produces a continuous sweep of far-UVC output wavelengths. (b), Using two pump lasers at respectively 445 nm and 473 nm, sum-frequency generation is demonstrated at 229.5 nm. The spectra, showing the normalized detected power, are recorded with two different optical spectrometers, the UV spectrometer having significantly higher resolution. As such the broader spectral appearance of the pump lasers is not their true spectral width as all spectra are under-sampled and merely reflect the resolution of the spectrometer.
