Characterisation of nonlinear conversion and crystal quality in Nd- and Yb-doped YAB (original) (raw)

Growth and evaluation of ytterbium-doped yttrium aluminum borate as a potential self-doubling laser crystal

Journal of the Optical Society of America B, 1999

The doped nonlinear optical crystal, ytterbium: yttrium aluminum borate, Yb 3ϩ :YAl 3 (BO 3 ) 4 , has been grown with good optical quality in a high-temperature solution from K 2 Mo 3 O 10 and B 2 O 3 fluxes. Room-and lowtemperature absorption and fluorescence spectra have been measured, and spectral parameters have been calculated. The ground-state energy-level splitting is 581 cm Ϫ1 . The emission lifetime, the absorption cross section, and the peak emission cross section are 0.68 ms, 3.4 ϫ 10 Ϫ20 cm 2 , and 0.8 ϫ 10 Ϫ20 cm 2 , respectively. In comparison with established laser crystals, the results for the cross sections, lifetime, and energy splitting suggest that this crystal has potential as an efficient self-frequency-doubled laser operating in the green.

Twinning and “natural quasi-phase matching” in Yb:YAB

Applied Physics B, 2006

Defects obtained during crystal growth of many laser and nonlinear crystals limit their commercial potential, as is the case of the yttrium aluminium borate family. Typically, in Yb:YAB, birefringent phase-matching is used to obtain self frequency doubled output from a fundamental laser operating near 1 µm. Many crystals however show signs of twin inversion defects during crystal growth resulting in the reversal of the sign of the nonlinear coefficient and hence can result in quasi-phasematched-like structures. In this report we examine the second harmonic conversion characteristics of a 3.8 mm thick birefringently phase matched Yb:YAB crystal which is then examined in more detail by slicing into four thinner sections each approximately 400 µm thick. Etching of crystal surfaces reveals clear boundaries between reversed domains, which under illumination with a laser at 1.064 µm shows a cancellation of the nonlinear conversion along the interface of the two regions.

Continuous-wave laser properties of the self-frequency-doubling YAl_3(BO_3)_4: Nd crystal

Journal of The Optical Society of America B-optical Physics, 1998

In this paper the laser properties of Nd 3ϩ ion in yttrium aluminum borate crystal are systematically investigated under continuous-wave end pumping by using a Ti:sapphire tunable laser. Spectral characteristics in the diode-pumping region are analyzed, and no significant excited-state absorption of pumping radiation is predicted. Internal losses are determined to be as low as 0.02 cm Ϫ1 and a net-gain cross section of 1.7 ϫ 10 Ϫ19 cm 2 for the infrared laser line at 1062 nm. Different cavity configurations devoted to demonstrate the possibility of low threshold, high slope efficiency at 1062 nm, and efficient laser generation at 531 nm by self-frequency doubling are investigated for the ordinary and extraordinary beams.

Up-conversion luminescence in the Nd 3q :YAB self frequency doubling laser crystal

In this work the infrared to visible up-converted luminescence in neodymium-doped yttrium aluminium borate has been systematically investigated in the excitation spectral range corresponding to diode pumping 700–850 nm under continuous wave and pulsed pumping. Three visible bands centred at 535, 590 and 675 nm are observed, these emissions mainly departing from the excited state 4 G. By using a simple rate equation model to fit the experimental results, it has been 7r2 concluded that this excited state is populated via up-conversion energy transfer between Nd 3q ions. q

Thermal and laser properties of Yb:YAl3(BO3)4 crystal

Journal of Crystal Growth, 2003

Large optical-quality Yb:YAl 3 (BO 3 ) 4 (Yb:YAB) crystals have been grown by the flux method. The thermal properties of Yb:YAB crystal were measured for the first time. The thermal properties of Yb:YAB crystal with different Yb 3+ ion concentrations are also reported. The results show that the ytterbium concentration influences the properties of Yb:YAB crystal. The specific heat decreases with the increase of Yb 3+ ion concentrations in the experiment range. Apparently, the thermal expansion coefficient increases along the c-direction with the increase of Yb 3+ ion concentrations, while it changes slightly along the a-direction. The output laser in 1120-1140 nm ranges has been demonstrated pumped by InGaAs laser. The slope efficiency is 3.8%. The self-frequency-doubling output power of 1 mW is achieved. r

Self-frequency-doubling ytterbium lasers

Optical Review, 2005

Ytterbium-doped self-frequency-doubling lasers offer high efficiency, tunable, visible and near-infrared, cw and pulsed operation from compact devices. We review the performance of ytterbium-doped yttrium aluminium borate (Yb:YAB) self-frequency-doubling lasers. Because of the detailed dynamics of the interaction of the nonlinear pulse shaping process for mode-locking or for Q-switching self-frequency-doubled lasers, we observe pulse lengthening in each process when frequency doubling is optimised, with high average output power. However, for continuous wave operation, the self-frequency doubling process may be optimised to give highly efficient, robust, widely-tunable output in the visible as well as fundamental output in the infrared. #