Diode-laser pumping into the emitting level for efficient lasing of depressed cladding waveguides realized in Nd:YVO_4 by the direct femtosecond-laser writing technique

Abstract

Depressed cladding waveguides have been realized in Nd:YVO(4) employing direct writing technique with a femtosecond-laser beam. It was shown that the output performances of such laser devices are improved by the reduction of the quantum defect between the pump wavelength and the laser wavelength. Thus, under the classical pump at 808 nm (i.e. into the (4)F(5/2) level), a 100-μm diameter circular waveguide inscribed in a 0.7-at.% Nd:YVO(4) outputted 1.06-μm laser pulses with 3.0-mJ energy, at 0.30 optical efficiency and slope efficiency of 0.32. The pump at 880 nm (i.e.directly into the (4)F(3/2) emitting level) increased the pulse energy at 3.8 mJ and improved both optical efficiency and slope efficiency at 0.36 and 0.39, respectively. The same waveguide yielded continuous-wave 1.5-W output power at 1.06 μm under the pump at 880 nm. Laser emission at 1.34 μm was also improved using the pump into the (4)F(3/2) emitting level of Nd:YVO(4).

Ultrafast Laser Microprocessing of Transparent Dielectrics. New Schemes for the Fabrication of Photonic Devices

“…From these measurements some conclusions can be extracted. Firstly, the magnitude of the waveguide losses is similar to those previously reported for other cladding structures in other crystals [159,163,164]. Concerning Nd:YAG, very different values have been reported in previous works, that range from 0.12 [165] to 2.0 dB/cm [166], depending on the waveguide diameter and on the coupling wavelength.…”

Monolithic solid-state lasers for spaceflight

“…Recently, a double-clad direct-write waveguide Nd:YVO4 laser produced 3.8 mJ in pulsed pump operation and 1.5 W continuous-wave 22 . Direct-write Q-switched lasers have been realized through evanescent coupling to graphene 23 , carbon nanotubes 24 , acetate films 25 and with a codoped saturable absorber 26 .…”

Femtosecond writing of depressed cladding waveguides in strongly cumulative regime

“…This offers to write highly symmetric waveguides with similar propagation characteristics for both linear polarizations, unlike most of waveguides, written in alternative regimes of writing [18,22].…”