| 1. |
- Canalias, Carlota Canalias, et al.
(författare)
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Highly efficient periodically poled KTP-isomorphs with large apertures and extreme domain aspect-ratios
- 2018
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Ingår i: Nonlinear Frequency Generation and Conversion: Materials and Devices XVII. - : SPIE - International Society for Optical Engineering. - 9781510615175
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 2. |
- Barrett, Laura, et al.
(författare)
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High-contrast coercive field engineering for periodic poling of RbKTiOPO4 with Ba2+/K+ ion-exchange
- 2024
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 32:8, s. 14252-14260
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Tidskriftsartikel (refereegranskat)abstract
- We investigate a new method of coercive field engineering for periodic poling of RbKTiOPO4 (RKTP). By ion exchanging RKTP in a molten salt containing 7 mol% Ba(NO3)2 and 93 mol% KNO3 we achieve more than an order of magnitude difference in polarization switching time between the exchanged and non-exchanged regions. This method is used to fabricate periodic gratings of 2.92 µm in 1 mm thick bulk RKTP for second harmonic generation at 779 nm with a normalized conversion efficiency of 2%/Wcm. We show that the poled domain structures are stable at 300 °C, and that there is no bulk refractive index modification associated with the periodic ion exchange.
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| 3. |
- Barrett, Laura, et al.
(författare)
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Novel Coercive Field Engineering Method for Short Period KTiOPO4
- 2023
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Ingår i: 2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- The development of reliable periodic poling methods that allow for sub-µm quasi-phase matched (QPM) gratings and, at the same time, allow for waveguide implementation, is of paramount importance for a large number of applications. For instance, backward-wave optical parametric oscillators [1] are only viable if the QPM period is on the same order of magnitude as the wavelengths of the interacting waves. Furthermore, the integration of such QPM devices in a waveguide format would unveil countless possibilities in quantum optics employing the crystal as an ultrabright bi-photon source with unique spectral characteristics.
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| 4. |
- Bayraktar, Ömer, et al.
(författare)
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Quantum-polarization state tomography
- 2016
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Ingår i: PHYSICAL REVIEW A. - : American Physical Society. - 2469-9926. ; 94:2
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
- Bowers, Mark S., et al.
(författare)
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Feature issue introduction : advanced solid-state lasers
- 2022
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Ingår i: Optical Materials Express. - : Optica Publishing Group. - 2159-3930 .- 2159-3930. ; 12:6, s. 2283-2287
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Tidskriftsartikel (refereegranskat)abstract
- This Joint Issue of Optics Express and Optical Materials Express features 36 state of-the art articles written by authors who participated in the international conference Advanced Solid State Lasers held online from October 3-7, 2021. This review provides a summary of these articles covering a wide spectrum of topics around solid-state lasers from materials research to sources and from design innovation to applications.
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| 6. |
- Bowers, Mark S., et al.
(författare)
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Feature issue introduction : advanced solid-state lasers
- 2022
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 30:12, s. 20762-20766
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Tidskriftsartikel (refereegranskat)abstract
- This joint issue of Optics Express and Optical Materials Express features 36 state-of-the art articles written by authors who participated in the international conference advanced solid state lasers held online from October 3-7, 2021. This review provides a summary of these articles covering a wide spectrum of topics around solid-state lasers from materials research to sources and from design innovation to applications.
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| 7. |
- Campbell, S., et al.
(författare)
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Frequency-doubling in femtosecond laser inscribed periodically-poled potassium titanyl phosphate waveguides
- 2007
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Ingår i: Optics Express. - 1094-4087. ; 15:25, s. 17146-17150
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Campbell, S., et al.
(författare)
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Frequency doubling in femtosecond-written periodically-poled potassium titanyl phosphate waveguides
- 2007
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Ingår i: Lasers and Electro-Optics, 2007 European Conference on and the International Quantum Electronics Conference. - 1424409306 - 9781424409303 ; , s. 4386106-
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 9. |
- Campbell, S., et al.
(författare)
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Frequency doubling in femtosecond-written periodically-poled potassium titanyl phosphate waveguides
- 2007
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Ingår i: Conference on Lasers and Electro-Optics, 2007, CLEO 2007. - 9781557528346 ; , s. 4452462-
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Konferensbidrag (refereegranskat)abstract
- 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).
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| 10. |
- Canalias, Carlota, et al.
(författare)
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A KTiOPO4 nonlinear photonic crystal for blue second harmonic generation
- 2009
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 94:8
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Canalias, Carlota, et al.
(författare)
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Backward quasi phase matched second harmonic generation in sub-micron periodically poled KTiOPO4
- 2005
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Ingår i: 2005 Conference on Lasers & Electro-Optics (CLEO), Vols 1-3. - WASHINGTON : OPTICAL SOC AMERICA. ; , s. 2264-2266
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 15. |
- Canalias, Carlota, et al.
(författare)
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Backward quasi-phase-matched second-harmonic generation in submicrometer periodically poled flux-grown KTiOPO4
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 86:18, s. 181105-1-181105-3
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 16. |
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| 17. |
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| 18. |
- Canalias, Carlota, 1975-
(författare)
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Domain engineering in KTiOPO4
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 19. |
- Canalias, Carlota, et al.
(författare)
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Feature issue introduction : shaping and patterning crystals for optics
- 2017
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Ingår i: Optical Materials Express. - : OPTICAL SOC AMER. - 2159-3930 .- 2159-3930. ; 7:9, s. 3466-3470
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- 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
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| 20. |
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| 21. |
- Canalias, Carlota, et al.
(författare)
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High-resolution domain imaging on the nonpolar y-face of periodically poled KTiOPO4 by means of atomic force microscopy
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 83:4, s. 734-736
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 22. |
- Canalias, Carlota, et al.
(författare)
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In situ visualization of domain kinetics in flux grown KTiOPO4 by digital holography
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 102:6, s. 064105-
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 23. |
- Canalias, Carlota, et al.
(författare)
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Mirrorless optical parametric oscillator
- 2007
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 1:8, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 24. |
- Canalias, Carlota, et al.
(författare)
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Mirrorless optical parametric oscillators
- 2010
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Ingår i: Nonlinear Photonics (NP) 2010. - Washington, D.C. : OSA. - 9781557528964
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 25. |
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