Japanese Journal of Applied Physics · 1996 · 23 citations · 9 references
Natural SciencesElectrical EngineeringMaterials ScienceOptical MaterialsOpticsOptoelectronicsAbsorption SpectroscopyLaser DiodesNonlinear Optical MaterialsNonlinear OpticsOptical Properties Of SolidsRare-earth-doped MaterialsAbsorption SpectraAtomic Energy Level StructureEnergy Level TransitionsExcited-state AbsorptionNonlinear AbsorptionNonlinear Optical ResponseOptical AbsorptionOptical Signal Amplification
Using a modulated laser diode, dependence of a negative nonlinear absorption effect on both the wavelength and the sample length was observed in an erbium doped yttrium aluminum garnet crystal which has a four-level energy structure. The effect was seen at wavelengths of 787.4 to 788.6 nm in excited state absorption spectra which showed a peak corresponding to the transition from 4 I 13/2 to 2 H 11/2 in Er 3+ for sample lengths greater than 2.0 mm. An optical signal inverter which had a negative input-output characteristic was realized using the negative nonlinear absorption effect.
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