Sophie Vernay

Large and stable thickness coupling coefficients of [001]c-oriented KNbO3 and Li-modified (K,Na)NbO3 single crystals

Large thickness coupling factors kT⩽0.7 are measured in both [001]C-oriented (45° cut in the orthorhombic ac plane), monodomain and [001]C-poled, domain-engineered single crystals of KNbO3. kT is extremely stable over a large temperature range, remaining high (⩾0.65) even upon heating and cooling through the orthorhombic-tetragonal phase transition. This is likely related to another finding that spontaneously high kT values (⩽0.68) are observed in as-grown (unpoled), [001]C-cut, polydomain KNbO3 crystals. kT is also stable upon thinning to thicknesses below 60μm, as required for high-frequency applications. Finally, large kT values (⩽0.7) are reported in [001]C-poled, polydomain, Li-doped (K0.5Na0.5)NbO3.

Thin-disk Yb:KLu(WO 4 ) 2 laser with single-pass pumping

Single-pass pumping of a thin disk consisting of an only 50 microm thick epitaxial layer of 32 at.% Yb-doped KLu(WO(4))(2) grown on a 0.35 mm thick undoped KLu(WO(4))(2) substrate is demonstrated. The thin-disk laser delivered 9 W of continuous wave output power near 1030 nm with a slope efficiency of 77%.

YAl3(BO3)4: a novel NLO crystal for frequency conversion to UV wavelengths

A new family of nonlinear optical (NLO) crystals is presented for the generation of ultraviolet (UV) light by frequency conversion. Included in this family are REAl3(BO3)4 with RE = Y, Lu and other rare earths. Phase matching properties of YAl3(BO3)4 (i.e., YAB) are described in detail.

Diffusion Bonding of Monoclinic Yb:KY(WO4)2/KY(WO4)2 and its Continuous-Wave and Mode-Locked Laser Performance

Diffusion bonding of strongly anisotropic double tungstate crystals with high quality interfaces was successfully implemented. The bonded Yb:KY(WO4)2/KY(WO4)2 composite crystals showed an impressive performance both in the continuous-wave and mode-locked laser regime. More than 800 mW of continuous-wave output power at 1.04 µm and slope efficiencies up to 70% were obtained at room temperature without cooling. In the passively mode-locked regime, pulse durations as short as 66 and 62 fs have been achieved directly from the oscillator and with external compression, respectively.

Characterization and laser performance of a new material: 2 at. % Nd:YAG grown by the Czochralski method

We report on the optical quality and laser performance of Czochralski-grown 2-at. %-doped Nd:YAG. Using a diode pumped laser in an end pumped configuration, we compare the laser performance of this material with the performance of 1-at. %-doped Nd:YAG and 0.7-at. %-doped Nd:YVO4 crystals. Experimental results show the superior performance of 2-at. % Nd:YAG over Nd:YVO4. With a pump power of 25.7 W, a maximum output power of 12.3 W with a slope efficiency of 57% and an optical-to-optical efficiency of 48% were achieved.

Segmented grown Yb:KY(WO 4 ) 2 /KY(WO 4 ) 2 for use in continuous-wave and mode-locked lasers

Segmented growth of monoclinic Yb:KY(WO(4))(2) on KY(WO(4))2(2) substrates was successfully implemented and its excellent laser performance demonstrated. High slope efficiencies up to 80% and an output power of 375 mW were achieved under Ti:sapphire laser pumping in the continuous-wave regime. In the passively mode-locked regime, pulses as short as 99 fs with an average output power of 69 mW were obtained.

Second harmonic generation in the new nonlinear optical material BiB/sub 3/O/sub 6/

Summary form only given. The monoclinic BiB/sub 3/O/sub 6/ is a new nonlinear optical material. Recently, large BiB/sub 3/O/sub 6/ crystals have been grown with good optical quality. Meanwhile, the Sellmeier coefficients were published an calculations indicated the suitability for nonlinear applications. We report on an investigation of the properties of this material for frequency doubling (SHG) of e.g. Nd:YAG laser radiation (1064 nm). The 5 mm long crystal used in these investigations was cut in the y-z-plane. The two crystal facets were AR coated for 1064 nm and 532 nm. Important parameters for efficient SHG are the linear losses at 1064 nm and the effective nonlinearity. Both parameters were measured across the crystals aperture (of 3/spl times/3 mm) with a spatial resolution of 120 /spl mu/m. In addition, we determined the temperature and the angular acceptance bandwidth.

Low threshold optical parametric oscillation and third harmonic generation in the new nonlinear optical material BiB/sub 3/O/sub 6/

Summary form only given. We report on a type I (o /spl rarr/ ee) BIBO OPO pumped by 532 nm ns laser pulses. We also investigated the generation of third harmonic 355 nm UV radiation. Frequency tripling in BIBO is of interest since the short wavelength transmission limit at 286 nm is significantly shorter than that of KTP (350 nm). The OPO was excited by the second harmonic of a Q-switched Nd:YVO/sub 4/ laser system that generates 6 ns long 1064 nm pulses at a repetition rate of 10 kHz with an average power of 6 W. The BIBO OPO consisted of a 11 mm long crystal (aperture size: 2.4 /spl times/ 2.9 mm/sup 2/) and a resonator of two plane mirrors with reflectivities for the signal wave of 99% and 70-94%, respectively. The performance of the BIBO OPO was compared with similar OPOs of KTP and LBO. This comparison indicates that the BIBO OPO generated the highest output power. In addition the energy density at threshold was 5 and 17 times lower than those of the KTP and the LBO OPO, respectively.

Diffusion Bonding of Monoclinic Yb:KY(WO 4 ) 2 /KY(WO 4 ) 2 and Its Continuous-Wave Laser Operation

Diffusion bonding of the strongly anisotropic Yb:KY(WO4)2and KY(WO4)2crystals was successfully demonstrated. Efficient continuous-wave laser operation with slope efficiencies as high as 70% and 811 mW output power was obtained.

Mode-locked laser operation of a diffusion-bonded Yb:KY(WO 4 ) 2 /KY(WO 4 ) 2 Crystal

We report the shortest pulses (62 fs) ever produced with an Yb-doped monoclinic double tungstate laser by passive mode-locking of diffusion-bonded Yb:KY(WO₄)₂/KY(WO₄)₂ achieving an average power of 182 mW at 1029 nm.