Excited-state absorption of Tm3+-doped single crystals at photon-avalanche wavelengths

Abstract

Excited-state absorption (ESA) spectra calibrated in units of cross sections are reported in the case of Tm3+-doped YAG, YAP, and Y2O3 single crystals around wavelengths at which photon-avalanche absorptions were observed recently. The peak ESA cross sections are compared with those obtained theoretically by using the Judd–Ofelt approach.

Blue luminescence in Tm3+-doped KGd(WO4)2 single crystals

“…4. One part of the electronic population of the 3 F 2 + 3 F 3 levels then decayed non-radiatively to the 3 H 4 level, as observed in other hosts [3][4][5], and another part absorbed another photon pump up to the 1 D 2 level. The decay from the 3 H 4 to 3 H 6 , 3 F 4 and 3 H 5 levels generated emissions at 801 nm, 1.48 mm and 2.3 mm, respectively.…”

“…We found in the literature that in other thuliumdoped materials, the population of the 1 D 2 and 1 G 4 levels was only achieved by ESA [3][4][5]15]. However, ESA processes in KGW pumping at 688 nm were not possible because the energy difference between the 3 H 4 and 1 D 2 levels (14876 cm À1 ) and the 3 F 4 and 1 G 4 levels (15125 cm À1 ) is greater than the energy of a photon pump (14535 cm À1 ).…”

“…Thulium ions are a natural choice for obtaining blue fluorescence around 450 nm ( 1 D 2 -3 F 4 transition) and 480 nm ( 1 G 4 -3 H 6 transition) after excitation around 690, 790, and 1200 nm on the 3 F 2 + 3 F 3 , 3 H 4 and 3 H 5 energy levels, respectively. Until now, blue emissions by up-conversion processes in thuliumdoped materials were only achieved by excited state absorption (ESA) with one [2][3][4] or two [5] pump sources. In this paper we report the generation of blue emissions in thulium-doped KGd(WO 4 ) 2 (hereafter KGW) single crystals at 454 and 479 nm by the sequential two-photon excitation process (STEP) under a single pumping at 688 nm.…”

Excited-state absorption measurements of Tm3+-doped crystals

“…Often referred to as a pump-probe technique [1], ESA measurements have been extensively studied in the past [1][2][3][4][5][6]. Either pump or probe beams can be operated in pulsed or continuous wave (cw) mode.…”

Técnica de bombeio e prova para medidas de absorção de estado excitado e de emissão estimulada, em materiais sólidos dopados com íons terras raras

“…Uma cascata dos dois amplificadores é utilizada para se obter o espectro diferencial de transmissão o qual resulta em medidas de AEE, absorção de estado fundamental (AEF) e também emissão estimulada (EE). No caso pulsado, 6,[19][20][21] o qual não será abordado aqui, é possível estudar simultâneamente as transições AEE a partir de estados com diferentes valores de tempo de vida. No entanto, este método oferece menor sensibilidade e pior razão sinal ruído do que o método contínuo, o qual pode ser eficientemente aplicado para medidas de AEE a partir de níveis com valores de tempo de vida longo, como os que são aqui discutidos.…”