LED-pumped Er:Cr:YSGG

Er:Cr:YSGG is a well know crystal with laser emission at 2.79 μm [1] useful for medical applications and particularly for dentistry [2]. Energy transfer between Cr and Er allows to pump this crystal with flashlamps. In a search for new sources emitting in the SWIR, we propose to revisit this crystal with a new way of pumping: with LEDs. Er:Cr:YSGG generally operates on its ${ }^{4} \mathrm{I}_{11 / 2}{ }^{-4} \mathrm{I}_{13 / 2}$ transition for laser emission at 2.79 μm. Its ${ }^{4} \mathrm{I}_{13 / 2}{ }^{-4} \mathrm{I}_{15 / 2}$ transition around 1.6 $\mu \mathrm{m}$ can also be investigated for spontaneous emission. Indeed, this wavelength range is interesting for high-brightness, spectrally broadband and incoherent sources in the SWIR adapted for InGaAs cameras. In order to collect the spontaneous emission efficiently, a geometry of luminescent concentrator (LC) can be used [3]. The purpose of this work is to investigate the performance of Er:Cr:YSGG on both transitions.