Transient and persistent spectral holes were burned in the $^{7}F_{0}\ensuremath{-}^{5}D_{0}$ transition of ${\mathrm{Eu}}^{3+}$ ions in macromonolithic transparent porous nanocrystalline $\ensuremath{\gamma}$- ${\mathrm{Al}}_{2}$ ${\mathrm{O}}_{3}$ produced by sol-gel technology. An unusual temperature dependence of the transient hole width was observed that differs markedly from that in either crystalline or disordered systems. This temperature dependence is explained in terms of Raman processes involving sizeresonant vibrations of the nanoparticles comprising the structure. Possible mechanisms of hole burning are suggested.Transient and persistent spectral holes were burned in the $^{7}F_{0}\ensuremath{-}^{5}D_{0}$ transition of ${\mathrm{Eu}}^{3+}$ ions in macromonolithic transparent porous nanocrystalline $\ensuremath{\gamma}$-${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$ produced by sol-gel technology. An unusual temperature dependence of the transient hole width was observed that differs markedly from that in either crystalline or disordered systems. This temperature dependence is explained in terms of Raman processes involving sizeresonant vibrations of the nanoparticles comprising the structure. Possible mechanisms of hole burning are suggested.

Physical review. B, Condensed matterAug 1, 199643 citations

Spectral hole burning and excited electrons in Sm2+ -doped Al2O3−SiO2 glasses

Masayuki Nogami, Yoshihiro Abe

Persistent spectral hole burning in the $f\ensuremath{\rightarrow}f$ transition and changes in the $f\ensuremath{\rightarrow}d$ transition spectra upon laser irradiation were investigated in ${\mathrm{Sm}}^{2+}$ -doped ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}{\ensuremath{-}\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$ glasses prepared by a sol-gel process. The hole was burned in the ${}^{7}{F}_{0}{\ensuremath{\rightarrow}}^{5}{D}_{0}$ line of ${\mathrm{Sm}}^{2+}$ ions using a DCM dye laser at 77 K and the dependence of the burning efficiency on laser power and burning time was measured. The hole depth increased with increasing laser irradiation time, reaching up to $\ensuremath{\sim}12%$ of the total intensity within a few hundred seconds. Neither an antihole around the burned hole nor a change in the fluorescence line narrowing spectrum were observed after hole burning. The hole depth linearly increased with increasing the incident laser power up to $\ensuremath{\sim}1{\mathrm{W}/\mathrm{m}\mathrm{m}}^{2},$ indicating a single-photon hole-burning process. On the other hand, laser irradiation with a wavelength corresponding to the energy of the ${4f}^{6}\ensuremath{\rightarrow}{4f}^{5}5d$ transition resulted in a decrease of both the absorption and fluorescence intensities but no formation of a hole. It was concluded that the electrons excited in the ${4f}^{5}5d$ level were further excited into the conduction band of the host matrix by a two-photon absorption process and then captured in the trapping center.Persistent spectral hole burning in the $f\ensuremath{\rightarrow}f$ transition and changes in the $f\ensuremath{\rightarrow}d$ transition spectra upon laser irradiation were investigated in ${\mathrm{Sm}}^{2+}$-doped ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}{\ensuremath{-}\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$ glasses prepared by a sol-gel process. The hole was burned in the ${}^{7}{F}_{0}{\ensuremath{\rightarrow}}^{5}{D}_{0}$ line of ${\mathrm{Sm}}^{2+}$ ions using a DCM dye laser at 77 K and the dependence of the burning efficiency on laser power and burning time was measured. The hole depth increased with increasing laser irradiation time, reaching up to $\ensuremath{\sim}12%$ of the total intensity within a few hundred seconds. Neither an antihole around the burned hole nor a change in the fluorescence line narrowing spectrum were observed after hole burning. The hole depth linearly increased with increasing the incident laser power up to $\ensuremath{\sim}1{\mathrm{W}/\mathrm{m}\mathrm{m}}^{2},$ indicating a single-photon hole-burning process. On the other hand, laser irradiation with a wavelength corresponding to the energy of the ${4f}^{6}\ensuremath{\rightarrow}{4f}^{5}5d$ transition resulted in a decrease of both the absorption and fluorescence intensities but no formation of a hole. It was concluded that the electrons excited in the ${4f}^{5}5d$ level were further excited into the conduction band of the host matrix by a two-photon absorption process and then captured in the trapping center.

Physical review. B, Condensed matterJul 1, 199741 citations

Transient and persistent spectral holes were burned in the $^{7}F_{0}\ensuremath{-}^{5}D_{0}$ transition of

{\mathrm{Eu}}^{3+}

ions in macromonolithic transparent porous nanocrystalline $\ensuremath{\gamma}$-

{\mathrm{Al}}_{2}

{\mathrm{O}}_{3}

produced by sol-gel technology. An unusual temperature dependence of the transient hole width was observed that differs markedly from that in either crystalline or disordered systems. This temperature dependence is explained in terms of Raman processes involving sizeresonant vibrations of the nanoparticles comprising the structure. Possible mechanisms of hole burning are suggested.

Persistent spectral hole burning in the $f\ensuremath{\rightarrow}f$ transition and changes in the $f\ensuremath{\rightarrow}d$ transition spectra upon laser irradiation were investigated in

{\mathrm{Sm}}^{2+}

-doped ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}{\ensuremath{-}\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$ glasses prepared by a sol-gel process. The hole was burned in the ${}^{7}{F}_{0}{\ensuremath{\rightarrow}}^{5}{D}_{0}$ line of

{\mathrm{Sm}}^{2+}

ions using a DCM dye laser at 77 K and the dependence of the burning efficiency on laser power and burning time was measured. The hole depth increased with increasing laser irradiation time, reaching up to $\ensuremath{\sim}12%$ of the total intensity within a few hundred seconds. Neither an antihole around the burned hole nor a change in the fluorescence line narrowing spectrum were observed after hole burning. The hole depth linearly increased with increasing the incident laser power up to $\ensuremath{\sim}1{\mathrm{W}/\mathrm{m}\mathrm{m}}^{2},$ indicating a single-photon hole-burning process. On the other hand, laser irradiation with a wavelength corresponding to the energy of the ${4f}^{6}\ensuremath{\rightarrow}{4f}^{5}5d$ transition resulted in a decrease of both the absorption and fluorescence intensities but no formation of a hole. It was concluded that the electrons excited in the

{4f}^{5}5d

level were further excited into the conduction band of the host matrix by a two-photon absorption process and then captured in the trapping center.