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  • 1.
    Bayraktar, Ömer
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Swillo, Marcin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Kvantelektronik och -optik, QEO.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Björk, Gunnar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Kvantelektronik och -optik, QEO.
    Quantum-polarization state tomography2016Inngår i: PHYSICAL REVIEW A, ISSN 2469-9926, Vol. 94, nr 2, artikkel-id 020105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose and demonstrate a method for quantum-state tomography of qudits encoded in the quantum polarization of N-photon states. This is achieved by distributing N photons nondeterministically into three paths and their subsequent projection, which for N = 1 is equivalent to measuring the Stokes (or Pauli) operators. The statistics of the recorded N-fold coincidences determines the unknown N-photon polarization state uniquely. The proposed, fixed setup manifestly rules out any systematic measurement errors due to moving components and allows for simple switching between tomography of different states, which makes it ideal for adaptive tomography schemes.

  • 2. Campbell, S.
    et al.
    Thomson, R. R.
    Hand, D. P.
    Kar, A. K.
    Reid, D. T.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Frequency doubling in femtosecond-written periodically-poled potassium titanyl phosphate waveguides2007Inngår i: Lasers and Electro-Optics, 2007 European Conference on and the International Quantum Electronics Conference, 2007, s. 4386106-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The second-harmonic conversion efficiency within the PPKTP waveguide is investigated using two separate tunable CW Ti:sapphire lasers at 800 nm and 980 nm. Results show strong conversion efficiency which imply that the local damage-induced index modification does not adversely affect the periodic domain structure in the material.

  • 3. Campbell, S.
    et al.
    Thomson, R. R.
    Hand, D. P.
    Kar, A. K.
    Reid, D. T.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Frequency doubling in femtosecond-written periodically-poled potassium titanyl phosphate waveguides2007Inngår i: Conference on Lasers and Electro-Optics, 2007, CLEO 2007, 2007, s. 4452462-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Frequency doubling is demonstrated in femtosecond-laser-created single-mode waveguides written in a periodically-poled potassium titanyl phosphate crystal. Conversion efficiencies of 0.22%/W (0.02%/W) were obtained for first (third) order phasematching at 980nm (800nm).

  • 4. Campbell, S.
    et al.
    Thomson, R. R.
    Hand, D. P.
    Kar, A. K.
    Reid, D. T.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Frequency-doubling in femtosecond laser inscribed periodically-poled potassium titanyl phosphate waveguides2007Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 15, nr 25, s. 17146-17150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Frequency doubling has been achieved in femtosecond-laser-inscribed single-mode waveguides written in two periodically-poled potassium titanyl phosphate crystals. A conversion efficiency of 0.22 %W-1 was obtained for first-order quasi-phase matching at 980 nm and an efficiency of 0.02 %W-1 for third-order quasi-phase matching at 800 nm.

  • 5.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Domain engineering in KTiOPO42005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Ferroelectric crystals are commonly used in nonlinear optics for frequency conversion of laser radiation. The quasi-phase matching (QPM) approach uses a periodically modulated nonlinearity that can be achieved by periodically inverting domains in ferroelectric crystals and allows versatile and efficient frequency conversion in the whole transparency region of the material.

    KTiOPO4 (KTP) is one of the most attractive ferroelectric non-linear optical material for periodic domain-inversion engineering due to its excellent non-linearity, high resistance for photorefractive damage, and its relatively low coercive field. A periodic structure of reversed domains can be created in the crystal by lithographic patterning with subsequent electric field poling. The performance of the periodically poled KTP crystals (PPKTP) as frequency converters rely directly upon the poling quality. Therefore, characterization methods that lead to a deeper understanding of the polarization switching process are of utmost importance.

    In this work, several techniques have been used and developed to study domain structure in KTP, both in-situ and ex-situ. The results obtained have been utilized to characterize different aspects of the polarization switching processes in KTP, both for patterned and unpatterned samples.

    It has also been demonstrated that it is possible to fabricate sub-micrometer (sub-μm) PPKTP for novel optical devices. Lithographic processes based on e-beam lithography and deep UV-laser lithography have been developed and proven useful to pattern sub- μm pitches, where the later has been the most convenient method. A poling method based on a periodical modulation of the K-stoichiometry has been developed, and it has resulted in a sub-μm domain grating with a period of 720 nm for a 1 mm thick KTP crystal. To the best of our knowledge, this is the largest domain aspect-ratio achieved for a bulk ferroelectric crystal. The sub-micrometer PPKTP samples have been used for demonstration of 6:th and 7:th QPM order backward second-harmonic generation with continuous wave laser excitation, as well as a demonstration of narrow wavelength electrically-adjustable Bragg reflectivity.

  • 6.
    Canalias, Carlota Canalias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Tjörnhamman, Staffan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Viotti, Anne-Lise
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Liljestrand, Charlotte
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Highly efficient periodically poled KTP-isomorphs with large apertures and extreme domain aspect-ratios2018Inngår i: Nonlinear Frequency Generation and Conversion: Materials and Devices XVII, SPIE - International Society for Optical Engineering, 2018, Vol. 10516, artikkel-id 105160WKonferansepaper (Fagfellevurdert)
    Abstract [en]

    Since the early 1990's, a substantial effort has been devoted to the development of quasi-phased-matched (QPM) nonlinear devices, not only in ferroelectric oxides like LiNbO3, LiTaO3 and KTiOPO4 (KTP), but also in semiconductors as GaAs, and GaP. The technology to implement QPM structures in ferroelectric oxides has by now matured enough to satisfy the most basic frequency-conversion schemes without substantial modification of the poling procedures. Here, we present a qualitative leap in periodic poling techniques that allows us to demonstrate devices and frequency conversion schemes that were deemed unfeasible just a few years ago. Thanks to our short-pulse poling and coercive-field engineering techniques, we are able to demonstrate large aperture (5 mm) periodically poled Rb-doped KTP devices with a highly-uniform conversion efficiency over the whole aperture. These devices allow parametric conversion with energies larger than 60 mJ. Moreover, by employing our coercive-field engineering technique we fabricate highlyefficient sub-μm periodically poled devices, with periodicities as short as 500 nm, uniform over 1 mm-Thick crystals, which allow us to realize mirrorless optical parametric oscillators with counter-propagating signal and idler waves. These novel devices present unique spectral and tuning properties, superior to those of conventional OPOs. Furthermore, our techniques are compatible with KTA, a KTP isomorph with extended transparency in the mid-IR range. We demonstrate that our highly-efficient PPKTA is superior both for mid-IR and for green light generation-as a result of improved transmission properties in the visible range. Our KTP-isomorph poling techniques leading to highly-efficient QPM devices will be presented. Their optical performance and attractive damage thresholds will be discussed.

  • 7.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Fragemann, A.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Ferroelectric domain imaging on the nonpolar facesof periodically poled KTiOPO42003Konferansepaper (Fagfellevurdert)
  • 8.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Hirohashi, Junji
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Polarization switching characteristics of flux grown KTiOPO4 and RbTiOPO4 at room temperature2005Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 97, nr 12, s. 124105-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A study of polarization-switching characteristics under an applied electrical field at room temperature is presented for flux-grown KTiOPO4 and RbTiOPO4. By optimizing the experimental conditions, we determined the coercive field and the domain-switching time quantitatively by direct observation of the switching current. For both isomorphs, the inverse of the polarization-switching time, 1/t(s), follows an exponential dependence on the applied field E in low-field regime, and a linear dependence on E in the high-field regime. Domain morphology of KTiOPO4 based on selective etching reveals laminar structures elongated in the b crystallographic direction. An estimation of the domain-wall velocity shows that the domain speed in the polar direction is, at least, two orders of magnitude larger than in the a-b plane. The velocity along the b direction is similar to 30 times larger than along the a axis.

  • 9.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Mirov, Sergey
    Taira, Takunori
    Boulanger, Benoit
    Feature issue introduction: shaping and patterning crystals for optics2017Inngår i: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 7, nr 9, s. 3466-3470Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Shaping and patterning of bulk or thin layer crystals and ceramics are one of the new frontiers in the field of laser and nonlinear optics. These technical aspects are rarely published, but they are crucial for the fundamental studies as well as for technology and applications. This special issue features 15 articles that focus on the orienting, cutting, polishing, coating, bonding, writing guides, or poling crystals and ceramics for bulk- or micro-optics. We have here a corpus of contributions describing the techniques as well as the gain they bring in terms of functionality or performance of the fabricated components devoted to optics and photonics. (C) 2017 Optical Society of America

  • 10.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Nordlöf, Mats
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    A KTiOPO4 nonlinear photonic crystal for blue second harmonic generation2009Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, nr 8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A nonlinear photonic crystal with a rectangular domain lattice of 6.09x6 mu m(2) has been fabricated and characterized in flux-grown KTiOPO4. It was used to demonstrate continuous-wave and multiple beam tunable blue second harmonic generation.

  • 11.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Nordlöf, Mats
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Two-Dimensional Nonlinear Photonic Crystal in KTiOPO4 for CW Second Harmonic Blue Light Generation2007Inngår i: 2007 CONFERENCE ON LASERS & ELECTRO-OPTICS/QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2007), NEW YORK: IEEE , 2007, s. 404-405Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report on fabrication and characterization of a nonlinear photonic crystal with a rectangular lattice in a KTiOPO4 crystal. The structure was used to demonstrate CW tunable second harmonic generation in the blue regime.

  • 12.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Counter-Propagating QPM Parametric Interactions: A Mirrorless OPO in sub-µm Periodically Poled KTiOPO42007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report on the first experimental demonstration of mirrorless optical parametric oscillation. The counter-propagating idler and signal oscillate without an external cavity in a sub-µm periodically poled KTiOPO4 crystal, reaching an efficiency of 16.5%.

  • 13.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Mirrorless optical parametric oscillator2007Inngår i: Nature Photonics, ISSN 1749-4885, Vol. 1, nr 8, s. 459-462Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Parametric interaction of counterpropagating photons has the unique property of automatically establishing distributed feedback and thus realizing novel sources of coherent and tunable radiation, such as mirrorless optical parametric oscillators. This device does not require alignment or any optical components other than the second-order nonlinear medium itself(1). Here we present the first experimental demonstration of such an oscillator, which was made feasible by quasi phase-matching in a nonlinear photonic structure with submicrometre periodicity. This type of oscillator has been extensively discussed as a theoretical possibility(1-5). It generates signal and idler waves in the near- and mid-infrared, respectively, and exhibits unique and useful spectral properties. The oscillator signal is essentially a wavelength-shifted replica of the pump spectrum, and the bandwidth of the idler is two orders of magnitude narrower than that of the pump. It also has very low output wavelength sensitivity to temperature variations.

  • 14.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Clemens, R.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Sub-micronperiodically poled flux grown KTiOPO4 for optical applications2003Konferansepaper (Fagfellevurdert)
  • 15.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Clemens, R.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Sub-micronperiodically poled flux-grown KTiOPO4 for optical applications2003Konferansepaper (Fagfellevurdert)
  • 16.
    Canalias, Carlota
    et al.
    KTH, Tidigare Institutioner, Fysik.
    Pasiskevicius, Valdas
    KTH, Tidigare Institutioner, Fysik.
    Clemens, Rosalie
    KTH, Tidigare Institutioner, Fysik.
    Laurell, Fredrik
    KTH, Tidigare Institutioner, Fysik.
    Submicron periodically poled flux-grown KTiOPO42003Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 82, nr 24, s. 4233-4235Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A submicron domain grating has been created in a bulk ferroelectric. Electron-beam lithography and electric-field poling were used to fabricate the 800 nm period grating in a 0.5-mm-thick flux-grown KTiOPO4 sample. The domain structure was characterized with an atomic force microscope and was used to demonstrate electrically amplitude adjustable Bragg reflections.

  • 17.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Fokine, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Backward quasi phase matched second harmonic generation in sub-micron periodically poled KTiOPO42006Inngår i: CLEO/QELS 2006, Optical Society of America, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    1mm thick KTiOPO4 was poled with 720nm domain period by employing UVlithography, chemical patterning and electric field poling. The structure was used to demonstrate 6 and 7 order quasi-phase matched backward second harmonic generation.

  • 18.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Fokine, Michael
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Backward quasi phase matched second harmonic generation in sub-micron periodically poled KTiOPO42005Inngår i: 2005 Conference on Lasers & Electro-Optics (CLEO), Vols 1-3, WASHINGTON: OPTICAL SOC AMERICA , 2005, s. 2264-2266Konferansepaper (Fagfellevurdert)
    Abstract [en]

    1mm thick KTiOPO4 was poled with 720nm domain period by employing UV-lithography, chemical patterning and electric field poling. The structure was used to demonstrate 6 and 7 order quasi-phase matched backward second harmonic generation.

  • 19.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Fokine, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Backward quasi-phase-matched second-harmonic generation in submicrometer periodically poled flux-grown KTiOPO42005Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, nr 18, s. 181105-1-181105-3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A 1 turn thick flux-grown KTiOPO4 sample was poled with a 720 nm domain period by employing deep-UV laser lithography, chemical patterning, and electric field poling. An atomic force microscope was used to characterize the periodic domain structure. The sample was used to demonstrate sixth and seventh order quasi-phase-matched backward second-harmonic generation.

  • 20.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Fokine, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Progress in Sub-Micrometer Periodicity of Quasi-Phase Matching Structures2009Inngår i: 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009, IEEE , 2009, s. 906-907Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report on the progress in fabrication of sub-micrometer ferroelectric domain gratings in KTiOPO4. Periods as short as 565 nm have been created in the bulk of the crystal by electric-filed poling.

  • 21.
    Canalias, Carlota
    et al.
    KTH, Tidigare Institutioner, Fysik.
    Pasiskevicius, Valdas
    KTH, Tidigare Institutioner, Fysik.
    Fragemann, Anna
    KTH, Tidigare Institutioner, Fysik.
    Laurell, Fredrik
    KTH, Tidigare Institutioner, Fysik.
    High-resolution domain imaging on the nonpolar y-face of periodically poled KTiOPO4 by means of atomic force microscopy2003Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 83, nr 4, s. 734-736Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The inverse piezoelectric effect is used to produce high-resolution images of ferroelectric domains in periodically poled KTiOPO4 crystals on their nonpolar y-face using atomic force microscopy. We demonstrate that the technique is convenient for studying the nucleation and growth of domains in a periodically poled KTiOPO4 sample.

  • 22.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Advances in KTP-Family Materials2007Konferansepaper (Fagfellevurdert)
  • 23.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Periodic poling of KTiOPO4: From micrometer to sub-micrometer domain gratings2006Inngår i: Ferroelectrics (Print), ISSN 0015-0193, E-ISSN 1563-5112, Vol. 340, nr 1, s. 27-47Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Some novel techniques to do periodic poling of KTP are described. Emphasis on ways to avoid domain broadening and merging of domains is presented with reference to the original properties of flux grown KTP. For sub-Am structures E-beam lithography and deep UV-laser lithography were used to pattern the samples, and chemical process to promote selective poling to obtain high quality domain gratings in up to 1 mm thick samples.

  • 24.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Periodical domains gratings go nano2009Konferansepaper (Fagfellevurdert)
  • 25.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Sub-µmperiodically poled KTiOPO42009Konferansepaper (Fagfellevurdert)
  • 26.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Grilli, Simonetta
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    De Natale, P.
    Ferraro, P.
    In situ visualization of domain kinetics in flux grown KTiOPO4 by digital holography2007Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 102, nr 6, s. 064105-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The fast dynamic evolution of ferroelectric domains during electric field poling in flux grown KTiOPO4 crystals was investigated online by a digital holography based technique. The dependence of the ferroelectric domain kinetics on the electric field temporal wave form and poling history was studied. High-speed imaging by means of a complementary metal-oxide-semiconductor image sensor camera allowed in situ measurement of the domain wall propagation speed under different poling conditions. The results also give evidence of the strong influence of the dielectric surface layer in this material.

  • 27.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Nordlöf, M.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Domain engineering in KTiOPO4: from periodic poling to self-assembled2007Konferansepaper (Fagfellevurdert)
  • 28.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Strömqvist, Gustav
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Mirrorless optical parametric oscillators2010Inngår i: Nonlinear Photonics (NP) 2010, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present the experimental implementation of a mirrorless optical parametric oscillator based on sub-μm periodically poled KTiOPO4. The poling process for sub-μm gratings and the unique properties of the device will be discussed.

  • 29.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Wang, Shunhua
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Nucleation and growth of periodic domains during electric field poling in flux-grown KTiOPO4 observed by atomic force microscopy2006Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 88, nr 3, s. 032905-1-032905-3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The domain structure of periodically poled KTiOPO4 crystals were studied on both the polar and nonpolar faces utilizing a voltage-modulated atomic force microscope. The measurements give information of domain nucleation, growth, and merging. Two different kind of overpoling behaviors have been observed depending on the magnitude of the applied field.

  • 30.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    Liljestrand, Charlotte
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Advances in QPM Devices Based on KTP Isomorphs2013Konferansepaper (Fagfellevurdert)
  • 31.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Liljestrand, Charlotte
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Sub-wavelength domain engineering in KTP isomorphs: QPM devices with counter-propagating photons2013Inngår i: 2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), New York: IEEE , 2013, s. 6600156-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We review the recent advances in fabrication of ferroelectric-domain gratings of sub-μm periodicity in KTP and Rb-doped KTP for counter-propagating second-order nonlinear optical interactions. Their performance as QPM devices will be discussed.

  • 32.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Sub-micrometer quasi-phased-matched devices2011Inngår i: Nonlinear Optics: Materials, Fundamentals and Applications 2011, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present the fabrication of bulk sub-micrometer ferroelectric domain gratings in KTiOPO4 for QPM counter-propagating interactions. We demonstrate that bulk Rb-doped KTiOPO4 is a promising candidate for fine-pitch periodic poling.

  • 33.
    Canalias, Carlota
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Viotti, A-L
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Coetzee, RS
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Liljestrand, C
    KTH.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Periodically Poled KTP with Sub-wavelength Periodicity: Nonlinear Optical Interactions with Counter Propagating Waves2018Inngår i: Optics InfoBase Conference Papers, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present the recent development on periodically poled nonlinear crystals with subwavelength periodicities as short as 500 nm. These devices show conversion efficiencies larger than 45%. Their unique properties will be presented and discussed.

  • 34. Chaitanya Kumar, S.
    et al.
    Samanta, G. K.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Ebrahim-Zadeh, M.
    6.2 W, Continuous-Wave, Single-Frequency, Yb-Fiber-Based Green Source at 532 nm Using Periodically-Poled KTiOPO42009Konferansepaper (Fagfellevurdert)
  • 35. Clemens, R.
    et al.
    Karlsson, H.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Wittborn, J.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Rao, K.V.
    Characterisation of periodically poled ferroelectricsusing scanning probe microscopy2001Konferansepaper (Fagfellevurdert)
  • 36.
    Coetzee, Riaan S.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Investigations of Laser Induced Damage in KTiOPO4 and Rb:KTiOPO4 at 1 mu m and 2 mu m2015Inngår i: PACIFIC RIM LASER DAMAGE 2015: OPTICAL MATERIALS FOR HIGH-POWER LASERS, 2015, Vol. 9532, artikkel-id 95320BKonferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the most practical means of generating tunable mid-infrared output is by using cascaded parametric down-conversion from 1 mu m, where efficient and reliable high-energy nanosecond lasers are well established. The overall efficiency of the cascade relies heavily on the efficiency of the first down-conversion stage where it is beneficial to employ quasi-phase matched crystals such as periodically-poled Rb: KTiOPO4 (PPRKTP). Ultimately, the pulse energy at 2 mu m and the optimum design of the first cascade will depend on the maximum intensity which could be safely applied to these crystals and therefore these schemes mandate investigation of nanosecond laser-induced damage threshold in KTiOPO4 (KTP) and Rb:KTiOPO4 (RKTP) at 1.064 mu m and 2 mu m. In the context of high-energy systems, where the beams are at most loosely focused, the limiting energy fluence will be determined by the laser induced damage threshold (LIDT) of the bare surface. Therefore the LIDT of the bare surface is the lowest LIDT which has to be taken into account in design of robust 2 mu m parametric systems. We report surface LIDT measurements in KTP and RKTP with nanosecond pulses at 1.064 mu m and 2.1 mu m. We find that the reported LIDT for the bulk is far higher than that of the surface and therefore is unsuitable as a guide for the 2 mu m parametric system designs. LIDT values for KTP and RKTP with nanosecond pulses at 2 mu m have not been reported so far to the best of our knowledge.

  • 37.
    Coetzee, Riaan S.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laser induced damage thresholds of KTiOPO4 and Rb:KTiOPO4 at 1 μm and 2 μm2015Inngår i: Conference on Lasers and Electro-Optics Europe - Technical Digest, IEEE conference proceedings, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Optimum design of high-energy parametric down-conversion schemes mandate investigation of nanosecond laser-induced damage threshold in KTiOPO4 and Rb:KTiOPO4 at 1.064 μm and 2 μm. A surface damage threshold of 10 J/cm2 at 2 μm was determined for both materials.

  • 38.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Nanosecond laser induced damage thresholds in KTiOPO4 and Rb:KTiOPO4 at 1 µm and 2 µm2015Inngår i: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 5, nr 9, s. 2090-2095Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimum design of high-energy cascaded parametric down-conversion schemes from 1 μm requires accurate knowledge of the laser induced damage threshold (LIDT) of the nonlinear crystal employed. We report surface LIDT measurements in KTiOPO4 (KTP) and Rb:KTP (RKTP) with nanosecond pulses at 1.064 μm and 2.1 μm. LIDT results for nanosecond pulses at 2 μm for KTP and RKTP have not been previously reported to the best of our knowledge.

  • 39.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlotta
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laser Induced Damage Thresholds of KTP and RKTP2014Konferansepaper (Fagfellevurdert)
  • 40.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Low-threshold, mid-infrared backward-wave parametric oscillator with periodically poled Rb: KTP2018Inngår i: APL Photonics, ISSN 2378-0967, Vol. 3, nr 7, artikkel-id 071302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the development of a nanosecond mirrorless optical parametric oscillator (OPO) pumped at 1 mu m. The gain medium of the OPO was periodically poled Rubidium-doped KTP with a grating period of Lambda = 509 nm for the first order quasi-phase matching. For grating periods of this length, we demonstrate backward propagation of the signal field and forward propagation of the idler field. To the best of our knowledge, this is the first time such a counter-propagating geometry has been demonstrated in mirrorless OPOs. Pumping with a maximum energy of 6.48 mJ, the OPO yielded an overall conversion efficiency exceeding 53% with signal and idler energies of 1.96 mJ and 1.46 mJ, respectively. The generated signal and idler field spectra were measured to show narrowband linewidths on the order of 0.5 nm. We motivate that such a MOPO is ideal for seeding applications and discuss further improvements and work.

  • 41.
    Coetzee, Riaan Stuart
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Low-threshold, mid-infrared backward-wave parametric oscillator with periodically poled Rb:KTPManuskript (preprint) (Annet vitenskapelig)
  • 42.
    Coetzee, Riaan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Thilmann, Nicky
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laser induced damage thresholds at 1 µm and 2 µm for undoped and Rb-doped KTiOPO4 [invited]2015Konferansepaper (Fagfellevurdert)
  • 43.
    Coetzee, Riaan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Efficient backward-wave optical parametric oscillator with 500 nm-periodicity PPRKTP2018Inngår i: Optics InfoBase Conference Papers, Optical Society of America, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Backward-wave OPO with forward mid-infrared idler and backward signal generation is demonstrated in 500-nm-periodicity PPRKTP. The output energy of 2.39mJ and efficiency of 46.4% is obtained. This design has potential for broad tunability in mid-infrared.

  • 44.
    Cordero-Edwards, Kumara
    et al.
    CSIC, Catalan Inst Nanosci & Nanotechnol, Campus UAB, Barcelona 08193, Spain.;BIST, Campus UAB, Barcelona 08193, Spain.;Univ Geneva, DPMC MaNEP, Quai Ernest Ansermet 24, CH-1211 Geneva, Switzerland..
    Kianirad, Hoda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Sort, Jordi
    UAB, Dept Fis, Edifici Cc, E-08193 Bellaterra, Spain.;ICREA, Pg Lluis Co 23, E-08010 Barcelona, Catalonia, Spain..
    Catalan, Gustau
    CSIC, Catalan Inst Nanosci & Nanotechnol, Campus UAB, Barcelona 08193, Spain.;BIST, Campus UAB, Barcelona 08193, Spain.;ICREA, Pg Lluis Co 23, E-08010 Barcelona, Catalonia, Spain..
    Flexoelectric Fracture-Ratchet Effect in Ferroelectrics2019Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, nr 13, artikkel-id 135502Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The propagation front of a crack generates large strain gradients and it is therefore a strong source of gradient-induced polarization (flexoelectricity). Herein, we demonstrate that, in piezoelectric materials, a consequence of flexoelectricity is that crack propagation is helped or hindered depending on whether it is parallel or antiparallel to the piezoelectric polar axis. The discovery of crack propagation asymmetry proves that fracture physics cannot be assumed to be symmetric in polar materials, and indicates that flexoelectricity should be incorporated in any realistic model.

  • 45.
    Deyra, Loïc
    et al.
    Institut d’Optique, Univ Paris-Sud.
    Liljestrand, Charlotte
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Didierjean, Julien
    Institut d’Optique, Univ Paris-Sud.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Balembois, François
    Institut d’Optique, Univ Paris-Sud.
    Georges, Patrick
    Institut d’Optique, Univ Paris-Sud.
    High power single-crystal fiber CW 946 nm laser and blue generation based on Rubidium-doped PPKTP2013Inngår i: 2013 Conference on Lasers and Electro-Optics Europe and International Quantum Electronics Conference, IEEE conference proceedings, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Blue lasers have numerous applications in spectroscopy, underwater communication and material processing. Direct emission in the blue region can be achieved with laser diodes, with powers up to the watt level [1]. Higher powers require efficient laser operating around 950 nm to be frequency doubled to the blue spectrum, which usually suffer from a lower gain than conventional 1μm lasers. Generally, intracavity frequency doubling set-ups and pulsed operation are used to increase the second harmonic generation efficiency, with output powers up to 4 W in cw[2] and 1.3W in pulsed regime [3]. In the past few years, both lasers materials and non linear crystals have progressed enough to allow the very simple extracavity frequency doubling of continuous wave lasers in periodically poled materials to acceptable powers[4].

  • 46. Eismann, U.
    et al.
    Gerbier, F.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Trenec, G.
    Vigue, J.
    Chevy, F.
    Salomon, C.
    An all-solid-state laser source at 671 nm for cold-atom experiments with lithium2012Inngår i: Applied physics. B, Lasers and optics (Print), ISSN 0946-2171, E-ISSN 1432-0649, Vol. 106, nr 1, s. 25-36Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present an all-solid-state narrow-linewidth laser source emitting 670 mW output power at 671 nm delivered in a diffraction-limited beam. The source is based on a frequency-doubled diode-end-pumped ring laser operating on the 4F 3/2 → 4I 13/2 transition in Nd:YVO 4. By using periodically poled potassium titanyl phosphate (ppKTP) in an external buildup cavity, doubling efficiencies of up to 86% are obtained. Tunability of the source over 100 GHz is accomplished. We demonstrate the suitability of this robust frequency-stabilized light source for laser cooling of lithium atoms. Finally, a simplified design based on intracavity doubling is described and first results are presented.

  • 47. Grilli, Simonetta
    et al.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Ferraro, P.
    De Natale, P.
    Control of lateral domain spreading in congruent lithium niobate by selective proton exchange2006Inngår i: Applied physics letters, ISSN 0003-6951, Vol. 89, nr 3, s. 032902-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Proton exchange was observed to increase the poling voltage for congruent lithium niobate. Patterned proton exchange was then used to control domain nucleation and inhibit broadening of reversed domains. Periodically proton exchanged samples were used to form domain gratings by electric field poling just using planar electrodes and without need for poling current control. The reversed domain gratings had a duty cycle faithfully reproducing that of the proton exchanged pattern with straight domain walls parallel to the x face, thus demonstrating that high-fidelity reversed domain patterning is possible to obtain by a relatively simple process.

  • 48.
    Grilli, Simonetta
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Ferraro, P
    Alfieri, D
    De Natale, P
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Laurell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Characterization of fast dynamic evolution of ferroelectric domains in KTiOPO4 by digital holographyInngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087Artikkel i tidsskrift (Annet vitenskapelig)
  • 49. Hart, James L.
    et al.
    Liu, Shi
    Lang, Andrew C.
    Hubert, Alexander
    Zukauskas, Andrius
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Beanland, Richard
    Rappe, Andrew M.
    Arredondo, Miryam
    Taheri, Mitra L.
    Electron-beam-induced ferroelectric domain behavior in the transmission electron microscope: Toward deterministic domain patterning2016Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 94, nr 17, artikkel-id 174104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on transmission electron microscope beam-induced ferroelectric domain nucleation and motion. While previous observations of this phenomenon have been reported, a consistent theory explaining induced domain response is lacking, and little control over domain behavior has been demonstrated. We identify positive sample charging, a result of Auger and secondary electron emission, as the underlying mechanism driving domain behavior. By converging the electron beam to a focused probe, we demonstrate controlled nucleation of nanoscale domains. Molecular dynamics simulations performed are consistent with experimental results, confirming positive sample charging and reproducing the result of controlled domain nucleation. Furthermore, we discuss the effects of sample geometry and electron irradiation conditions on induced domain response. These findings elucidate past reports of electron beam-induced domain behavior in the transmission electron microscope and provide a path towards more predictive, deterministic domain patterning through electron irradiation.

  • 50.
    Holmgren, Stefan
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Canalias, Carlota
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Pasiskevicius, Valdas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Single-shot pulse characterization with high spatial resolution using localized nonlinearities and čerenkov2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Čerenkov phase-matching of second-order nonlinearities localized in the regions of ferroelectric domain walls in KTiOPO4 is used to realize a single-shot FROG arrangement for ultrashort pulse characterization, which can be used from visible to mid-infrared.

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