Efeito anomalo nas medidas de lente termica em vidros com pontos quanticos de CdTe / Anomalous effect in thermal lens measurements in CdTe quantum dot doped glasses

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Semiconductor doped glasses are of great interest because of their non-linear optical properties and short response time due to quantum confinement. In this work, we used the thermal lens technique to determine the thermal diffusivity (a ) and the behavior of the temperature coefficient of the refractive index (dn/dT ) in CdTe doped borosilicate glasses treated at 540 º C for different time intervals. The thermal lens measurements showed an anomalous behavior at high intensities of the excitacion beam, which consists in a signal reduction for long acquisition time. This characteristics was confirmed using another photothermal technique, namely, the mirage effect. One possible explanation for this behavior is the saturation of the electronic levels of the quantum-dot. The suppresion of a given absorption band reduces the refractive index at lower frequencies, thus originating a divergent lens, which is in agreement with the observed signal reduction

ASSUNTO(S)

vidro - propriedades termicas quantum points glass pontos quanticos photothermal techniques tecnicas fototermicas thermal waves ondas termicas

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