Haojia Zhang

Spectroscopic Characteristics and Laser Performance of

(Nd_xY_0.9-xLa_0.1)₂O₃ (x=0.005-0.04) transparent ceramics were fabricated by conventional solid-state processing. The radiative spectral properties of the ceramic samples were evaluated by fitting the Judd-Ofelt model with the absorption and emission data. (Nd_xY_0.9-xLa_0.1)₂O₃ ceramics have broad absorption and emission bands with a radiative decay time of 328 μs. The absorption cross section at 806 nm and stimulated emission cross section at 1078 nm are calculated to be 1.53 ×10^-20 and 5.22 × 10^-20 cm², respectively. The product of quantum efficiency and the ionic concentration (ηN) exhibited a peak value at 1.5 at% Nd³⁺ ion concentration, while the lifetime decreases dramatically from 300 μs (0.5 at% Nd) to 49 μs (4.0 at% Nd). With 1.0 at% Nd:Y_1.8La_0.2O₃ ceramics acting as a laser medium, continuous-wave output power of 1.03 W was obtained at 1079.5 nm under an absorbed pump power of 7.2 W, corresponding to a slope efficiency of 18.4%.

{\rm Nd}{:}{\rm Y}_{1.8}{\rm La}_{0.2}{\rm O}_{3}

Highly transparent Yb, Ho doped (YLa)(2)O-3 ceramic was fabricated by conventional ceramic processing with nanopowders. The absorption and emission spectra of the ceramic was investigated. The energy transfer mechanism between Yb3+ and Ho3+ was also discussed. The strong emission band around 2 mu m indicated that the Yb-Ho: (Y(0.9)0La(0.10))(2)O-3 transparent ceramic is a promising gain medium for the generation of 2 mu m laser emissions. The laser operation of Yb-Ho co-doped (YLa)(2)O-3 ceramic at 2.1 mu m is first reported.

Transparent Ceramics

Temperature dependent absorption and emission cross-sections of 5 at% Yb(3+) doped yttrium lanthanum oxide (Yb:YLO) ceramic between 80K and 300 K are presented. In addition, we report on the first demonstration of ns pulse amplification in Yb:YLO ceramic. A pulse energy of 102 mJ was extracted from a multi-pass amplifier setup. The amplification bandwidth at room temperature confirms the potential of Yb:YLO ceramic for broad bandwidth amplification at cryogenic temperatures.

Spectral and laser properties of Yb and Ho co-doped (YLa)2O3 transparent ceramic

A diode-pumped sub-picosecond laser is realized with Yb3+-doped yttrium lanthanum oxide transparent ceramic Yb:(Y0.9La0.1)2O3 as the gain medium for the first time. By using Gires-Tournois interferometer mirrors and chirped mirror for dispersion compensation and semiconductor saturable absorber mirror for passive mode-locking, laser pulse as short as 730 fs was obtained at the central wavelength of 1033 nm and repetition rate of 65.5 MHz. Under the maximum pump power of 6 W at 976 nm, the output power is 92 mW.

Temperature dependent emission and absorption cross section of Yb 3+ doped yttrium lanthanum oxide (YLO) ceramic and its application in diode pumped amplifier

Both Er/Yb:Y<inf>2</inf>O<inf>3</inf> and Er/Yb:(Y<inf>0.9</inf>La<inf>0.1</inf>)<inf>2</inf>O<inf>3</inf> transparent ceramics have the same absorbption and emission spectra. But Er/Yb:(Y<inf>0.9</inf>La<inf>0.1</inf>)<inf>2</inf>O<inf>3</inf> has wider absorbption and emission bandwidths, and longer fluorescent lifetime.

Diode-pumped passively mode-locked yb 3+ -doped yttrium lanthanum oxide ceramic sub-picosecond laser

The effects of Nd3+ concentration on the visible fluorescence spectroscopic properties of Nd:(Y0.9La0.1)2O3 transparent ceramics are investigated. Under 270 nm excitation, three emission peaks are observed at 396, 426, and 633 nm. When the Nd3+ concentration is increased, intensities of the peaks at 396 and 426 nm increase while the 633 nm peak become weak due to the fluorescence re-absorption effect. Broad luminescence band centered at 426 nm is observed from the fluorescence spectrum stimulated at 358 nm. The emission intensity increases with the increase of Nd3+ ion content firstly, then decreases owing to the concentration quenching of Nd3+ ions.

Spectral properties of Er/Yb:(Y 0.9 La 0.1 ) 2 O 3 and Er/Yb:Y 2 O 3 transparent ceramics

The single phase of Y<inf>2</inf>O<inf>3</inf> was observed in (Eu<inf>0.05</inf>Y<inf>0.85</inf>La<inf>0.10</inf>)<inf>2</inf>O<inf>3</inf> phosphors. The crystal size and luminescence intensity increase with the increase of calcination temperature. The maximum peaks of excitation and emission are at 261nm and 613nm.

Effects of Nd3+ concentration on properties of yttrium lanthanum oxide transparent ceramics

The full width at half maximum of the Raman peaks in Yb:(Y<inf>1-x</inf>La<inf>x</inf>)<inf>2</inf>O<inf>3</inf> transparent ceramics were increased, while the intensity and phonon energy decreased with the La<inf>2</inf>O<inf>3</inf> content x.

Luminescence properties of Eu 3+ -doped yttrium lanthanum oxide phosphors

The absorption bandwidth of Nd:(Y<inf>1-X</inf>La<inf>x</inf>)<inf>2</inf>O<inf>3</inf> (x=0, 0.05, 0.10) transparent ceramics are 4 nm for x=0 and 8 nm for x>0, respectively. The fluorescent lifetimes are increased with the increase of x due to the glasslike structure of Y<inf>2-2x</inf>La<inf>2x</inf>O<inf>3</inf>.