Multi-wavelength infrared and visible light emissions from Ho/Yb co-doped cubic yttria stabilized zirconia and lutecia stabilized zirconia single crystals excited by 980 nm

Under 980 nm excitation, Ho 3+ in Ho/Yb co-doped materials can emit light spanning the infrared to green spectral regions through down-conversion and multiphoton up-conversion processes. The multi-wavelength infrared emissions from Yb/Ho co-doped yttria-stabilized zirconia (YSZ) enable fast wavelength hopping, making it highly valuable for secure laser communication systems. However, achieving efficient and intense multi-wavelength emission remains challenging. In this work, high-quality YSZ, YSZ:Yb 3 Ho 0.1 , Lutetia-stabilized zirconia (LuSZ) and LuSZ:Yb 3 Ho 0.1 single crystals were grown by the optical floating zone method. A first-time comparative study reveals distinct photoluminescence characteristics between YSZ:Yb 3 Ho 0.1 and LuSZ:Yb 3 Ho 0.1 crystals under 980 nm excitation. Both systems show emission peaks at 2450, 2100, 1845, 1230, 1050, 650, and 538 nm from the down-conversion and up-conversion photoluminescence (DCPL and UCPL). Notably, LuSZ:Yb 3 Ho 0.1 exhibits stronger UCPL peaks at 650 and 538 nm, attributed to its lower phonon energy. In contrast, YSZ: Yb 3 Ho 0.1 shows higher DCPL intensities infrared peaks at 2450, 2100, 1845, 1230, and 1050 nm, benefiting from its higher transmittance and phonon energy. The unique strong multi-wavelength infrared emission of YSZ:Yb 3 Ho 0.1 crystal enables rapid wavelength switching, highlighting its potential for secure laser communication.