Bismuth- and aluminum-codoped germanium oxide glasses for super-broadband optical amplification

Abstract

Broadband infrared luminescence from bismuth-doped germanium oxide glasses prepared by a conventional melting-quenching technique was discovered. The absorption spectrum of the glasses covered a wide range from the visible to the near-infrared wavelength regions and consisted of five broad peaks below 370, 500, 700, 800, and 1000 nm. The fluorescence spectrum exhibited broadband characteristics (FWHM) greater than 300 nm with a maximum at 1300 nm pumped by an 808-nm laser. The fluorescence lifetime at room temperature decreased with increasing Bi2O3 concentration in the glass. Codoping of aluminum and bismuth was indispensable for the broadband infrared luminescence in GeO2:Bi, Al glass.

Infrared luminescence and amplification properties of Bi-doped GeO2−Ga2O3−Al2O3 glasses

“…They were ascribed to the electron transitions of infrared active centers. 11,14 According to Ref. 15, the peaks at 700, 800, and 1000 nm are most probably originated from the transitions from the 3 P 0 level to the 1 D 2 , 3 P 2 , and 3 P 1 levels of the Bi + center.…”

“…11 In recent years, a number of hosts were investigated and broadband infrared luminescence was reported in silicate, 12,13 germanium, 14 phosphate, 15 and barium borate glasses. 16 It is exciting that optical amplification and lasing operation were also realized at present.…”

“…Actually, there are few subsequent investigations after the observation of ultrabroadband infrared luminescence from Bi-doped germanium glass. 14 The excitation spectra between 200 and 1000 nm are presented. Based on the result, the possible origin of excitation wavelength sensitive luminescence is discussed.…”

Nonlinear optical properties of Bi2O3-GeO2 glass at 800 and 532 nm

“…The large third-order optical susceptibility, v ð3Þ , due to the high polarizability of the heavymetal ions, allows applications of HMO glasses in optical limiting, optical amplifiers, and all-optical switching. [1][2][3][4][5][6][7][8][9][10][11][12] The HMO glasses containing bismuth oxide, Bi 2 O 3 , present large nonlinearity because of the high polarizability of the Bi 3þ ion due to its lone-electron pair in the valence shell and its large ionic radius. Moreover, with the introduction of Bi 2 O 3 in a HMO glass network, the number of nonbridging oxygen grows, and thus, the optical refractive and absorptive properties of the material increase.…”

“…The NL properties of glasses with Bi 2 O 3 were discussed by various authors that report large NL refractive index and high twophoton absorption (TPA) coefficients for certain glass compositions. [7][8][9][12][13][14][15] For instance, the influence of Bi 2 O 3 on the structural, thermal, and NL optical properties of phosphate glasses was investigated recently. 9 The results obtained show that the NL refractive indices increase with the increase of the Bi 2 O 3 concentration.…”