Abstract

CTH:YAG is a laser medium know for many years [1]. The atmospheric transmission properties and eye safe nature of this laser emitting at 2.1 µm make it attractive for many applications. Thanks to efficient energy transfer between Cr³⁺, Tm³⁺ and Ho³⁺, CTH:YAG has often been pumped in the visible by flashlamps [2]. CTH:YAG has also a remarkable broadband spectrum spanning from 1.7 µm to 2.15 µm (with a maximum for the longest wavelengths around 2.1 µm as shown in fig. 1b green curve). Sensing and inspection applications are growing with the emergence of low-cost image sensors in the SWIR (Short Wavelength InfraRed) range. Illumination sources in this wavelength band are limited: halogen, black body or low power LEDs as direct emission sources, and supercontinuum or thulium ASE as fiber sources. The purpose of this work is to show that CTH:YAG opens opportunities for innovative, high-brightness, spectrally-broadband and incoherent sources in the SWIR.

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