With AlGaN and AlGaInN, even shorter wavelengths are achievable. In the vicinity of-UV emitters at wavelengths about 360–395 nm are already low cost and sometimes encountered, as an example, as black light lamp replacements for inspection of anti-counterfeiting UV watermarks in files and financial institution notes, and for UV curing. https://focusz.de/beleuchten-sie-ihren-raum-die-geschichte-und-kunstfertigkeit-der-leuchtreklamen/