Femtosecond Fabrication of Waveguides in Ion-Doped Laser Crystals

Охримчук, А. Г.

doi:10.5772/12885

Cited by 17 publications

(21 citation statements)

References 37 publications

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“…2) Q-switched Waveguide Lasers: Q-switching of fs-laser written waveguide lasers was for example demonstrated by Okhrimchuk in Type III waveguides inscribed into a Nd:YAG crystal bonded to a Cr 4+ :YAG sample (Nd:YAG/Cr 4+ :YAG) working as saturable absorber [69].…”

Section: ) Continuous Wave Waveguide Lasersmentioning

confidence: 99%

Crystalline Waveguide Lasers in the Visible and Near-Infrared Spectral Range

Calmano

Müller

2015

IEEE J. Select. Topics Quantum Electron.

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This paper summarizes our recent results on crystalline waveguides and waveguide lasers fabricated by the femtosecond-laser writing technique. Highly efficient waveguide lasers emitting in the near infrared spectral range based on ytterbium and neodymium doped Y 3 Al 5 O 12 with slope efficiencies above 70% and continuous wave output powers of more than 5 W were demonstrated. Furthermore, pulsed laser operation of passively Q-switched Yb:YAG and Nd:YAG wavequide lasers was achieved by incorporating the saturable absorber Cr 4+ :YAG in a monolithic setup. Based on fs-laser written curved structures in Yb:YAG, efficient curved waveguide lasers could be demonstrated. Also, waveguide lasers in the visible spectral range were investigated. We achieved laser emission in the green, orange, red and deep-red spectral region and could demonstrate output powers of more than 1 W with waveguides based on praseodymium doped materials. Additionally, switchable and dual wavelength operation between the orange and red laser emission was achieved. By utilizing the nonlinear crystal KTiOPO 4 as substrate material for fs-laser inscription, nonlinear waveguides were realized. With these devices, efficient second harmonic generation into the blue and green spectral range was achieved.

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Section: ) Continuous Wave Waveguide Lasersmentioning

confidence: 99%

Crystalline Waveguide Lasers in the Visible and Near-Infrared Spectral Range

Calmano

Müller

2015

IEEE J. Select. Topics Quantum Electron.

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“…Refractive index change inside a track can be either negative or positive depending upon material. In non-linear LiNbO 3 crystal sign of the index change can be different for ordinary and extraordinary waves, but up to now waveguide profile was reported to be symmetrical relative to central axis of the femtosecond writing beam at least for cases when the writing beam had a perfect symmetrical shape [1,2]. In this paper we report an antisymmetric refractive index change that is associated with intrinsic crystal symmetry and not down to a beam profile.…”

Section: Introductionmentioning

confidence: 74%

“…The electro-optical and elasto-optical effects are eventually responsible for the observed phenomenon. Dependence of femtosecond modification upon direction of femtosecond writing was observed in LiNbO 3 crystal in [1] too. Although conditions of this experiment sufficiently differ from our one, nature of the phenomena could be the same, as LiNbO 3 crystal belongs the same space group as BBO crystal, and an anomaly was observed along the same optical axis (Y).…”

Section: Introductionmentioning

confidence: 85%

Antisymmetric Distribution of Permanent Refractive Index Change in β-BaB₂O₄Crystal Under Exposure of Femtosecond Pulses.

Охримчук

Grechin

Kokh

et al. 2013

MATEC Web of Conferences

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Abstract:We have observed unusual asymmetrical refractive index change as a result of femtosecond laser inscription in a crystal without center of inversion. Profile of the refractive index change exhibits sign turn within the domain of femtosecond pulse exposure.Femtosecond writing is a promising and flexible technology for fabrication of waveguide in transparent dielectrics. Low loss waveguides were demonstrated recently in both the rare-earth doped and non-linear ( χ(2) ) crystals. Efficient lasing, frequency doubling and electro-optical modulation were achieved. The waveguide patterning is due to a phenomenon of permanent refractive index change under exposure of tightly focused beam of a femtosecond laser. The waveguides are typically formed by one or more several elementary tracks. Refractive index change inside a track can be either negative or positive depending upon material. In non-linear LiNbO 3 crystal sign of the index change can be different for ordinary and extraordinary waves, but up to now waveguide profile was reported to be symmetrical relative to central axis of the femtosecond writing beam at least for cases when the writing beam had a perfect symmetrical shape [1,2]. In this paper we report an antisymmetric refractive index change that is associated with intrinsic crystal symmetry and not down to a beam profile. As far as we know such phenomenon was not observed before.We investigated the femtosecond writing in non-linear χ(2) BBO crystal in the regime of a single pulse exposure at the wavelength of 800 nm. Pulse duration was of 110 fs. We investigated X-cut plate of the crystal, thus femtosecond beam with Gaussian radial intensity distribution (M 2 =1.05) propagated perpendicular to the symmetry plane, which is singular in 3m space group of crystal symmetry. A lens with NA=0.55 was used to focus a beam at the depth of 130 µm under the crystal surface. Polarization of the femtosecond beam was parallel to either Z (extraordinary wave) or Y optical axes. Significantly different inscription thresholds were found in these cases at 200 nJ and 40 nJ correspondingly.Geometry and profiles of refractive index change were investigated by measuring the phase delay under microscopic observation along [100] crystallographic axis (perpendicular to the plate). We have found a complicated geometry of a modified region, which does not follow an axial symmetry of intensity distribution in writing beam, but its structure correlated with directions of crystallographic axes. Modified regions were sufficiently differed for extraordinary and ordinary types of writing beam (Fig1). Geometry in a form of elongated ellipsoid was found in the case of the writing beam of extraordinary type (E||Z). In this case an unusual antisymmetric profile of refractive index change with was found along the Y optical axis, that is, the refractive index change alters sign. Conversely, the profile of refractive index change was completely symmetrical along the Z axis. The refractive index change is birefringent, and the asymmetry was ...

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“…18 MS-DLW of waveguides has been demonstrated in different crystals such as LiNbO 3 , ZnSe, YCOB and recently in YAG. 11,12,[17][18][19] The use of larger repetition rates is probably the main enabling factor to refractive index increment since it leads to the appearance of controlled heat accumulation and self-annealing effects which are absent at lower repetition rates. 20,21 Due to the possibility of precisely achieving the desired core size and having refractive index changes similar to standard NIR fibers, these type of waveguides can exhibit very low coupling losses to fibers of around 0.1 dB, this being an important feature for fiber-coupled photonic chips.…”

Section: Introductionmentioning

confidence: 99%

“…4 DLW has been found especially appropriate for the local modification and controlled fabrication of laser waveguides in rare earth doped YAG crystals and ceramics. [5][6][7][8][9][10][11][12] In the simplest channel waveguide fabrication scheme (in which waveguides are constituted by either a single or double laser-written line tracks), waveguiding is produced at the stress affected volume (generally called Type II stress-induced waveguides) where the refractive index changes are produced through the piezo-optic effect. 10 In other cases, waveguiding is produced by a low-index cladding.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

Mendívil

Ródenas

Benayas

et al. 2015

Journal of Applied Physics

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The laser performance and crystalline micro-structural properties of near-infrared step-index channel waveguides fabricated inside Neodymium doped YAG laser ceramics by means of three-dimensional sub-picosecond pulse laser direct writing are reported. Fluorescence micro-mapping of the waveguide cross-sections reveals that an essential crystal lattice re-distribution has been induced after short pulse irradiation. Such lattice re-distribution is evidenced at the waveguide core corresponding to the laser written refractive index increased volume. The waveguides core surroundings also present diverse changes including slight lattice disorder and bi-axial strain fields. The step-index waveguide laser performance is compared with previous laser fabricated waveguides with a stress-optic guiding mechanism in absence of laser induced lattice re-distribution. V C 2015 AIP Publishing LLC. [http://dx

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Femtosecond Fabrication of Waveguides in Ion-Doped Laser Crystals

Cited by 17 publications

References 37 publications

Crystalline Waveguide Lasers in the Visible and Near-Infrared Spectral Range

Crystalline Waveguide Lasers in the Visible and Near-Infrared Spectral Range

Antisymmetric Distribution of Permanent Refractive Index Change in β-BaB₂O₄Crystal Under Exposure of Femtosecond Pulses.

Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

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Femtosecond Fabrication of Waveguides in Ion-Doped Laser Crystals

Cited by 17 publications

References 37 publications

Crystalline Waveguide Lasers in the Visible and Near-Infrared Spectral Range

Crystalline Waveguide Lasers in the Visible and Near-Infrared Spectral Range

Antisymmetric Distribution of Permanent Refractive Index Change in β-BaB2O4Crystal Under Exposure of Femtosecond Pulses.

Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

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Antisymmetric Distribution of Permanent Refractive Index Change in β-BaB₂O₄Crystal Under Exposure of Femtosecond Pulses.