ASL Crystal Research Articles

Direct generation of orthogonally polarized dual-wavelength continuous-wave and passively Q-switched vortex beam in diode-pumped Pr:YLF lasers.

We report on direct generation of an orthogonally polarized dual-wavelength vortex laser, for the first time to our knowledge, by means of a diode-pumped V-shaped Pr:YLF laser platform. A method of misaligning the folded mirror is proposed to realize the simultaneous orthogonally polarized dual-wavelength laser, while a method of orthogonally rotating the laser gain medium is proposed to generate an intracavity vortex beam (LG01 mode). With the two methods, in continuous-wave (CW) mode, we have achieved simultaneous lasing of an orthogonally polarized dual-wavelength vortex laser at 604 and 607nm with maximum output power of 237.7mW. Moreover, based on this operation, a simultaneous orthogonally polarized dual-wavelength passively Q-switched vortex laser is also realized by inserting a Co:ASL crystal into the laser resonator as a saturable absorber. This work provides the simplest way for direct generation of an orthogonally polarized dual-wavelength vortex laser for potential applications.

Diode-pumped continuous-wave a- and c-cut Pr:Sr0.5La0.5Mg0.5Al11.5O19 (Pr:ASL) visible lasers at 645 and 726 nm

Pr3+-doped Sr0.5La0.5Mg0.5Al11.5O19 (ASL) crystal along 〈100〉 direction was successfully grown using the Czochralski technique under azote atmosphere. Absorption and emission spectra of Pr:ASL crystal have been measured at room temperature. Continuous-wave laser operation of the a-cut and c-cut Pr:ASL samples under InGaN laser diode pumping has been demonstrated. For deep red laser operation at about 726 nm, the maximum output powers achieved from a-cut sample was 92.8 mW with slope efficiency of about 11.9%, while 46.6 mW with slope efficiency of 8.0% for the c-cut sample. For red laser at about 645 nm, maximum output powers of 49.2 mW and 42.8 mW were obtained for the a-cut sample and c-cut sample, corresponding to a slope efficiency of 6.7% and 8.5%, respectively.

Broadband Spectra and Efficient Laser Performance of a Disordered Nd:Sr0.7La0.3Mg0.3Al11.7O19 Crystal.

Here, we demonstrate the broadband spectra and efficient laser performance of a disordered Nd:Sr0.7La0.3Mg0.3Al11.7O19 (Nd:ASL) crystal. The polarized absorption and emission spectra were characterized and calculated with the Judd–Ofelt (J–O) theory, and the results show that this crystal has relatively large σ polarized absorption and emission cross sections, with peak emission cross sections of 4.5 × 10−20 cm2 at 1051 nm and an emission width of 30 nm at 1074 nm, which are favorable for pulsed lasers. The laser-diode-pumped continuous-wave (CW) and passively Q-switched lasers at 1051 nm were realized for the first time to our best knowledge. For CW laser, the maximum output power was 1.95 W with the slope efficiency of 42.6%, and for the passive Q-switching, the maximum output power was 0.73 W with the pulse width of 7.96 ns and peak power of 5.64 W. The results demonstrate that Nd:ASL crystal is a potential candidate for lasers, especially high-peak pulsed lasers such as Q-switching and mode-locking.

Crystal growth, spectroscopy and laser performances of Pr3+:Sr0.7La0.3Mg0.3Al11.7O19 (Pr:ASL).

We report on the crystal growth, spectroscopic properties and visible laser performances of Pr3+-doped Sr0.7La0.3Mg0.3Al11.7O19 (ASL). ASL crystals doped with 2 at.% and 4 at.% Pr3+ were grown by Czochralski method. The laser experiments were carried out in a plane-concave resonator under excitation at 486 nm, provided from a 2ω-OPSL. Efficient laser emission was obtained with an 8 mm long sample of Pr(2at.%):ASL. The maximum output power amounted to 267 mW, 52 mW, and 318 mW at an absorbed power of 1.2W for red, orange, and deep red emission, respectively.

Diode-pumped laser operation at 1053 and 900 nm in Sr1−xLax−yNdyMgxAl12−xO19 (Nd:ASL) single crystal

Neodymium-doped strontium lanthanum magnesium aluminoxide (Sr1−xLax−yNdyMgxAl12−xO19, Nd:ASL) single crystals were grown by the Czochralski technique. Branching ratios for both transitions 4F3/2→4I9/2 (900 nm) and 4F3/2→4I11/2 (1053 nm) were calculated to be 45% by the Judd–Ofelt theory based on polarized absorption spectra of Nd3+. The spectroscopic quality factors (X = Ω4/Ω6) of X = 0.87 for σ polarization and X = 1.55 for π polarization were calculated for 7 at.% Nd:ASL crystal. Quantum efficiency was calculated to be 74%. Laser operation was pumped by a 792 nm LD source. By adopting 7 at.% Nd:ASL crystal as gain media, output power of 5.7 W and slope efficiency of 50% were obtained at 1053 nm with output coupler T = 9.79% and achromatic lens focus of 75 and 150 mm. Output power of 6.9 W and slope efficiency of 36% at 1053 nm, together with output power of 1.72 W and slope efficiency of 17% at 900 nm were obtained in 5 at.% Nd:ASL crystal.

Continuous-wave laser at 453 nm based on frequency-doubled diode-pumped Nd:ASL crystal

Efficient and compact is generated by intracavity frequency doubling of a diode-pumped Sr1−x La x − y Nd y Mg x Al12 − x O19(Nd:ASL) laser at 906 nm. With 10.3 W of diode pump power and the frequency-doubling crystal LiB3O6 (LBO), a maximum output power of 281 mW in the blue spectra] range at 453 nm has been achieved, corresponding to an optical-to-optical conversion efficiency of 2.7%; the output power stability over 4 h is better than 3.8%.

Blue laser emission by intracavity second harmonic generation in Nd:ASL pumped by a tapered amplifier laser diode stabilized by a volume Bragg grating

We present the diode pumping of a Nd:ASL (Sr1-xLax-yNdyMgxAl12-xO19) crystal for second harmonic generation at 453 nm. We have developed a high-brightness pump source based on a tapered amplifier in an extended cavity with a volume Bragg grating for wavelength stabilization. A pump brightness of 110 MW cm-2 sr-1 is obtained with a linewidth lower than 80 pm at 798 nm. This laser source is used to pump a Nd:ASL crystal to obtain 300 mW at 906 nm and 53 mW at 453 nm by intracavity doubling with a LBO crystal.