Figure 7 | Scientific Reports

Figure 7

From: Experimental observation of gain in a resonantly pumped Pr3+-doped chalcogenide glass mid-infrared fibre amplifier notwithstanding the signal excited-state absorption

Figure 7

Simplified energy diagram of Pr3+ ions in the 4.1 μm resonant pumping scheme with the 5.5 μm signal laser. There are two potential downward transitions from the level (3F4, 3F3), with respective emissions at around 1.7 and 2.5 μm, and also the down transition (3F2, 3H6) → 3H4 exhibits emission around 2.5 μm.

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