Change search
Link to record
Permanent link

Direct link
BETA
Gallo, Katia, ProfessorORCID iD iconorcid.org/0000-0001-7185-0457
Publications (10 of 118) Show all publications
Baghban, M. A., Swillo, M. & Gallo, K. (2019). Second-Harmonic generation engineering in lithium niobate nanopillars. In: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015: . Paper presented at 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015, 21 June 2015 through 25 June 2015. Optical Society of America (OSA)
Open this publication in new window or tab >>Second-Harmonic generation engineering in lithium niobate nanopillars
2019 (English)In: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015, Optical Society of America (OSA) , 2019Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Optical Society of America (OSA), 2019
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-252105 (URN)2-s2.0-85063843875 (Scopus ID)
Conference
2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015, 21 June 2015 through 25 June 2015
Note

QC 20190802

Available from: 2019-08-02 Created: 2019-08-02 Last updated: 2019-08-02Bibliographically approved
Gatti, A., Brambilla, E., Gallo, K. & Jedrkiewicz, O. (2018). Golden ratio entanglement in hexagonally poled nonlinear crystals. Physical Review A: covering atomic, molecular, and optical physics and quantum information, 98(5), Article ID 053827.
Open this publication in new window or tab >>Golden ratio entanglement in hexagonally poled nonlinear crystals
2018 (English)In: Physical Review A: covering atomic, molecular, and optical physics and quantum information, ISSN 2469-9926, E-ISSN 2469-9934, Vol. 98, no 5, article id 053827Article in journal (Refereed) Published
Abstract [en]

This work analyzes the quantum state of twin photons and twin beams generated by parametric down-conversion in a hexagonally poled photonic crystal, characterized by the simultaneous presence of two nonlinear processes sustained by two vectors of the reciprocal lattice. In those special points of the fluorescence spectrum where the two processes coexist, we show that a tripartite entangled state is realized, equivalent to a single parametric process followed by a beam splitter. By proper angle tuning, a peculiar resonance condition is reached, with a transition to a four-mode entanglement, dominated by the golden ratio of the segment phi = (1 + root 5)/2. A maximal coherence between the two nonlinear processes is established here, as the overall process is shown to be equivalent to two independent parametric processes followed by a beam splitter. We offer an interpretation of the occurrence of the golden ratio in this system based on an analogy between the evolution of the light modes and the Fibonacci sequence.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2018
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-239762 (URN)10.1103/PhysRevA.98.053827 (DOI)000450547000011 ()2-s2.0-85057045758 (Scopus ID)
Note

QC 20190109

Available from: 2019-01-09 Created: 2019-01-09 Last updated: 2019-01-23Bibliographically approved
Jedrkiewicz, O., Gatti, A., Brambilla, E., Levenius, M., Tamosauskas, G. & Gallo, K. (2018). Golden Ratio Gain Enhancement in Coherently Coupled Parametric Processes. Scientific Reports, 8, Article ID 11616.
Open this publication in new window or tab >>Golden Ratio Gain Enhancement in Coherently Coupled Parametric Processes
Show others...
2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 11616Article in journal (Refereed) Published
Abstract [en]

Nonlinear optical processes are an essential tool in modern optics, with a broad spectrum of applications, including signal processing, frequency conversion, spectroscopy and quantum optics. Ordinary parametric devices nevertheless still suffer from relatively low gains and wide spectral emission. Here we demonstrate a unique configuration for phase- matching multiple nonlinear processes in a monolithic 2D nonlinear photonic crystal, resulting in the coherent parametric emission of four signal and idler modes, featuring an exponential gain enhancement equal to the Golden Ratio. The results indicate a new route towards compact high- brightness and coherent sources for multi- photon generation, manipulation and entanglement, overcoming limitations of conventional parametric devices.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-233277 (URN)10.1038/s41598-018-30014-7 (DOI)000440621000033 ()30072813 (PubMedID)2-s2.0-85051069479 (Scopus ID)
Funder
Swedish Research Council, VR 622-2010-526 621-2014-5407
Note

QC 20180821

Available from: 2018-08-21 Created: 2018-08-21 Last updated: 2018-08-21Bibliographically approved
Al-Shammari, R. M., Baghban, M. A., Al-attar, N., Gowen, A., Gallo, K., Rice, J. H. & Rodriguez, B. J. (2018). Photoinduced Enhanced Raman from Lithium Niobate on Insulator Template. ACS Applied Materials and Interfaces, 10(36), 30871-30878
Open this publication in new window or tab >>Photoinduced Enhanced Raman from Lithium Niobate on Insulator Template
Show others...
2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 36, p. 30871-30878Article in journal (Refereed) Published
Abstract [en]

Photoinduced enhanced Raman spectroscopy from a lithium niobate on insulator (LNOI)−silver nanoparticle template is demonstrated both by irradiating the template with 254 nm ultraviolet (UV) light before adding an analyte and before placing the substrate in the Raman system (substrate irradiation) and by irradiating the sample in the Raman system after adding the molecule (sample irradiation). The photoinduced enhancement enables up to an ∼sevenfold increase of the surface-enhanced Raman scattering signal strength of an analyte following substrate irradiation, whereas an ∼threefold enhancement above the surface-enhanced signal is obtained for sample irradiation. The photoinduced enhancement relaxes over the course of ∼10 h for a substrate irradiation duration of 150 min before returning to initial signal levels. The increase in Raman scattering intensity following UV irradiation is attributed to photoinduced charge transfer from the LNOI template to the analyte. New Raman bands are observed following UV irradiation, the appearance of which is suggestive of a photocatalytic reaction and highlight the potential of LNOI as a photoactive surface-enhanced Raman spectroscopy substrate.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
Raman, SERS, chemical enhancement, ferroelectric, photoinduced
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-235752 (URN)10.1021/acsami.8b10076 (DOI)000444793000096 ()2-s2.0-85052314803 (Scopus ID)
Note

QC 20181004

Available from: 2018-10-03 Created: 2018-10-03 Last updated: 2018-10-08Bibliographically approved
Al-Shammari, R. M., Al-Attar, N., Manzo, M., Gallo, K., Rodriguez, B. J. & Rice, J. H. (2018). Single-Molecule Nonresonant Wide-Field Surface-Enhanced Raman Scattering from Ferroelectrically Defined Au Nanoparticle Microarrays. ACS OMEGA, 3(3), 3165-3172
Open this publication in new window or tab >>Single-Molecule Nonresonant Wide-Field Surface-Enhanced Raman Scattering from Ferroelectrically Defined Au Nanoparticle Microarrays
Show others...
2018 (English)In: ACS OMEGA, ISSN 2470-1343, Vol. 3, no 3, p. 3165-3172Article in journal (Refereed) Published
Abstract [en]

Single-molecule detection by surface-enhanced Raman scattering (SERS) is a powerful spectroscopic technique that is of interest for the sensor development field. An important aspect of optimizing the materials used in SERS-based sensors is the ability to have a high density of "hot spots" that enhance the SERS sensitivity to the single-molecule level. Photodeposition of gold (Au) nanoparticles through electric-field-directed self-assembly on a periodically proton-exchanged lithium niobate (PPELN) substrate provides conditions to form well-ordered microscale features consisting of closely packed Au nanoparticles. The resulting Au nanoparticle microstructure arrays (microarrays) are plasmon-active and support nonresonant single-molecule SERS at ultralow concentrations (<10(-9)-10(-13) M) with excitation power densities <1 x 10(-3) W cm(-2) using wide-field imaging. The microarrays offer excellent SERS reproducibility, with an intensity variation of <7.5% across the substrate. As most biomarkers and molecules do not support resonance enhancement, this work demonstrates that PPELN is a suitable template for high-sensitivity, nonresonant sensing applications.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-225737 (URN)10.1021/acsomega.7b01285 (DOI)000427939400077 ()2-s2.0-85044217007 (Scopus ID)
Funder
Swedish Research Council, 622-2010-526; 621-2011-4040
Note

QC 20180410

Available from: 2018-04-10 Created: 2018-04-10 Last updated: 2018-04-10Bibliographically approved
Neumayer, S. M., Ievlev, A. V., Collins, L., Vasudevan, R., Baghban, M. A., Ovchinnikova, O., . . . Kalinin, S. V. (2018). Surface Chemistry Controls Anomalous Ferroelectric Behavior in Lithium Niobate. ACS Applied Materials and Interfaces, 10(34), 29153-29160
Open this publication in new window or tab >>Surface Chemistry Controls Anomalous Ferroelectric Behavior in Lithium Niobate
Show others...
2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 34, p. 29153-29160Article in journal (Refereed) Published
Abstract [en]

Polarization switching in ferroelectric materials underpins a multitude of applications ranging from nonvolatile memories to data storage to ferroelectric lithography. While traditionally considered to be a functionality of the material only, basic theoretical considerations suggest that switching is expected to be intrinsically linked to changes in the electrochemical state of the surface. Hence, the properties and dynamics of the screening charges can affect or control the switching dynamics. Despite being recognized for over 50 years, analysis of these phenomena remained largely speculative. Here, we explore polarization switching on the prototypical LiNbO3 surface using the combination of contact mode Kelvin probe force microscopy and chemical imaging by time-of-flight mass-spectrometry and demonstrate pronounced chemical differences between the domains. These studies provide a consistent explanation to the anomalous polarization and surface charge behavior observed in LiNbO3 and point to new opportunities in chemical control of polarization dynamics in thin films and crystals via control of surface chemistry, complementing traditional routes via bulk doping, and substrate-induced strain and tilt systems.

Keywords
ferroelectrics, surface chemistry, lithium niobate, switching dynamics, scanning probe microscopy, time-of-flight secondary ion mass spectrometry
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-235748 (URN)10.1021/acsami.8b09513 (DOI)000443654600098 ()2-s2.0-85052309282 (Scopus ID)
Note

QC 20181003

Available from: 2018-10-03 Created: 2018-10-03 Last updated: 2019-01-21Bibliographically approved
Brambilla, E., Jedrkiewicz, O., Gallo, K., Tamosauskas, G. & Gatti, A. (2018). Three and Four-Modes Parametric Processes in Hexagonally Poled Nonlinear Photonic Crystals. In: Yurish, S Y (Ed.), OPTICS, PHOTONICS AND LASERS: . Paper presented at 1st International Conference on Optics, Photonics and Lasers (OPAL' 2018) 9-11 May 2018, Barcelona, Spain (pp. 176-178). INT FREQUENCY SENSOR ASSOC-IFSA
Open this publication in new window or tab >>Three and Four-Modes Parametric Processes in Hexagonally Poled Nonlinear Photonic Crystals
Show others...
2018 (English)In: OPTICS, PHOTONICS AND LASERS / [ed] Yurish, S Y, INT FREQUENCY SENSOR ASSOC-IFSA , 2018, p. 176-178Conference paper, Published paper (Refereed)
Abstract [en]

We investigate the properties of the field emitted through parametric down-conversion (PDC) in a nonlinear photonics crystal (NPC) with a hexagonal poling pattern, both from a theoretical point of view and with an experiment performed at the University of Insubria. Considering the high gain regime of PDC, we demonstrate the existence of concurrent PDC processes mediated by two noncollinear poling vectors which are coherently coupled and reciprocally stimulated. We find that these non-standard 3-mode and 4-mode interaction processes undergo a substantial enhancement of the parametric gain with respect to the usual 2-mode PDC, and give rise to hot spots order of magnitudes brighter than standard 2-mode fluorescence which have been observed in the source far field. We performed a complete characterization of the source spectral-angular emission, finding a very good agreement between the experiment and the theoretical predictions.

Place, publisher, year, edition, pages
INT FREQUENCY SENSOR ASSOC-IFSA, 2018
Keywords
Nonlinear optics, Nonlinear photonics crystals, Parametric down-conversion
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-241234 (URN)000454436200051 ()
Conference
1st International Conference on Optics, Photonics and Lasers (OPAL' 2018) 9-11 May 2018, Barcelona, Spain
Note

QC 20190116

Available from: 2019-01-16 Created: 2019-01-16 Last updated: 2019-01-23Bibliographically approved
Al-attar, N., Al-Shammari, R. M., Manzo, M., Gallo, K., Rodriguez, B. J. & Rice, J. H. (2018). Wide-field surface-enhanced Raman scattering from ferroelectrically defined Au nanoparticle microarrays for optical sensing. In: Optics InfoBase Conference Papers: . Paper presented at CLEO: Applications and Technology, CLEO_AT 2018, 13 May 2018 through 18 May 2018. OSA - The Optical Society
Open this publication in new window or tab >>Wide-field surface-enhanced Raman scattering from ferroelectrically defined Au nanoparticle microarrays for optical sensing
Show others...
2018 (English)In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Conference paper, Published paper (Refereed)
Abstract [en]

The acquisition-time in optical sensors using SERS is vital value. Wide-field SERS is used to perform high-density of hot-spots of GNPs photodeposition on a periodically-protonexchanged- LiNbO3 which, leads to increase the sensitivity at ultralow probe concentrations.

Place, publisher, year, edition, pages
OSA - The Optical Society, 2018
Keywords
Gold, Gold nanoparticles, Lithium compounds, Niobium compounds, Surface scattering, Acquisition time, Hot spot, Optical sensing, Photo-deposition, Surface enhanced Raman Scattering (SERS), Wide field, Raman scattering
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-236441 (URN)10.1364/CLEO_AT.2018.AF2M.5 (DOI)2-s2.0-85049147251 (Scopus ID)9781557528209 (ISBN)
Conference
CLEO: Applications and Technology, CLEO_AT 2018, 13 May 2018 through 18 May 2018
Note

QC 20181022

Available from: 2018-10-22 Created: 2018-10-22 Last updated: 2019-01-23Bibliographically approved
Schollhammer, J., Baghban, M. A. & Gallo, K. (2017). Birefringence-free lithium niobate waveguides. In: Optics InfoBase Conference Papers: . Paper presented at The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017, 25 June 2017 through 29 June 2017. OSA - The Optical Society
Open this publication in new window or tab >>Birefringence-free lithium niobate waveguides
2017 (English)In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2017Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
OSA - The Optical Society, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-222926 (URN)000432564600930 ()2-s2.0-85039924595 (Scopus ID)9781557528209 (ISBN)
Conference
The European Conference on Lasers and Electro-Optics, CLEO_Europe 2017, 25 June 2017 through 29 June 2017
Note

QC 20180328

Available from: 2018-03-28 Created: 2018-03-28 Last updated: 2019-05-21Bibliographically approved
Kilinc, D., Blasiak, A., Baghban, M. A., Carville, N. C., Al-Adli, A., Al-Shammari, R. M., . . . Rodriguez, B. J. (2017). Charge and topography patterned lithium niobate provides physical cues to fluidically isolated cortical axons. Applied Physics Letters, 110(5), Article ID 053702.
Open this publication in new window or tab >>Charge and topography patterned lithium niobate provides physical cues to fluidically isolated cortical axons
Show others...
2017 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 110, no 5, article id 053702Article in journal (Refereed) Published
Abstract [en]

In vitro devices that combine chemotactic and physical cues are needed for understanding how cells integrate different stimuli. We explored the suitability of lithium niobate (LiNbO3), a transparent ferroelectric material that can be patterned with electrical charge domains and micro/ nanotopography, as a neural substrate. On flat LiNbO3 z-surfaces with periodically alternating charge domains, cortical axons are partially aligned with domain boundaries. On submicron-deep etched trenches, neurites are aligned with the edges of the topographical features. Finally, we bonded a bicompartmental microfluidic chip to LiNbO3 surfaces patterned by etching, to create isolated axon microenvironments with predefined topographical cues. LiNbO3 is shown to be an emerging neuron culture substrate with tunable electrical and topographical properties that can be integrated with microfluidic devices, suitable for studying axon growth and guidance mechanisms under combined topographical/chemical stimuli.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2017
Keywords
Axons, Topography, Fluidic devices, Etching, Atomic force microscopy
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-203961 (URN)10.1063/1.4975304 (DOI)000394057600046 ()2-s2.0-85011317245 (Scopus ID)
Funder
Swedish Research Council, 622-2010-526Swedish Research Council, 621-2014-5407
Note

QC 20170406

Available from: 2017-03-20 Created: 2017-03-20 Last updated: 2019-01-23Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7185-0457

Search in DiVA

Show all publications