Mechanical phase matching of birefringent non-linear crystals.

Second-order nonlinear processes such as second harmonic generation or parametric amplification have found numerous applications in the scientific and industrial world, from micromachining to petawatt laser facilities. These nonlinear interactions are mostly carried out in birefringent crystals because of their low cost and the possibility to operate at high powers Phase-matching configurations in birefringent crystals are determined by their refractive indexes. Here, we show that an important mechanical stress can be used to significantly change the phase-matching properties of a birefringent crystal.

Deep-UV 236.5 nm laser by fourth-harmonic generation of a single-crystal fiber Nd:YAG oscillator.

We demonstrate a deep-UV laser at 236.5 nm based on extracavity fourth-harmonic generation of a Q-switched Nd:YAG single-crystal fiber laser at 946 nm. We first compare two nonlinear crystals available for second-harmonic generation: LBO and BiBO.

3 W, 300 μJ, 25 ns pulsed 473 nm blue laser based on actively Q-switched Nd:YAG single-crystal fiber oscillator at 946 nm.

We report the realization of a frequency doubled, actively Q-switched and polarized oscillator based on Nd:YAG single-crystal fiber. A laser output of 8 W, 10 kHz, and 30 ns at 946 nm is reported. The laser is extracavity frequency doubled in a BiBO crystal to obtain 3 W and 300 μJ of blue laser with a beam quality of M(2)y=1.

Hybrid master oscillator power amplifier high-power narrow-linewidth nanosecond laser source at 257 nm.

We report on a high-power narrow-linewidth pulsed laser source emitting at a wavelength of 257 nm. The system is based on a master oscillator power amplifier architecture, with Yb-doped fiber preamplifiers, a Yb:YAG single crystal fiber power amplifier used to overcome the Brillouin limitation in glass fiber and nonlinear frequency conversion stages. This particularly versatile architecture allows the generation of Fourier transform-limited 15 ns pulses at 1030 nm with 22 W of average power and a diffraction-limited beam (M(2)<1.