| 1. |
- Adshead, Mason, et al.
(författare)
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Erbium implantation in thin film Lithium Niobate
- 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).
-
Konferensbidrag (refereegranskat)abstract
- Lithium niobate on insulator (LNOI), thanks to its electro-optic properties and second order nonlinearity, is one of the most promising photonic materials for on-chip implementation of a complex photonic integrated circuit (PIC) [1]. Integration of rare earth ion emitters (RIE), characterized by high coherent transitions in both optical and microwave domains, into LNOI is a very attractive perspective to fully exploit the potential of this material in quantum optics applications and for on chip light generation and amplification. By choosing Erbium ions these functionalities can be implemented at telecom wavelengths (~1550 nm). Erbium integration in LNOI can be achieved using the smart cut technique [2]. However, this approach implies heating the material up to ~1100 ºC, approaching the Curie temperature of lithium niobate (~1200 ºC). Ion implantation also permits the incorporation of RIE into the lithium niobate (LN) crystal structure, operating at lower temperature with high spatial precision of the doped region in a complex PIC.
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| 2. |
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| 3. |
- Al-Shammari, Rusul M., et al.
(författare)
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Antibacterial properties of lithium niobate crystal substrates
- 2023
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Ingår i: International Journal of Optomechatronics. - : Informa UK Limited. - 1559-9612 .- 1559-9620. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- The bactericidal properties of chemically patterned lithium niobate substrates under a super-bandgap UV light source is established. UV irradiation of lithium niobate surfaces inoculated with bacteria leads to antimicrobial activity compared to a glass substrate under similar conditions, as determined by surface enhanced Raman spectroscopy and corroborated with a fluorescence-based live/dead assay. This finding may expand the possible biomedical applications of lithium niobate.
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| 4. |
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| 5. |
- Al-Shammari, Rusul M., et al.
(författare)
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Photoinduced Enhanced Raman from Lithium Niobate on Insulator Template
- 2018
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:36, s. 30871-30878
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 6. |
- Al-Shammari, Rusul M., et al.
(författare)
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Single-Molecule Nonresonant Wide-Field Surface-Enhanced Raman Scattering from Ferroelectrically Defined Au Nanoparticle Microarrays
- 2018
-
Ingår i: ACS Omega. - : AMER CHEMICAL SOC. - 2470-1343. ; 3:3, s. 3165-3172
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Al-Shammari, Rusul M., et al.
(författare)
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Tunable Wettability of Ferroelectric Lithium Niobate Surfaces : The Role of Engineered Microstructure and Tailored Metallic Nanostructures
- 2017
-
Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 121:12, s. 6643-6649
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Tidskriftsartikel (refereegranskat)abstract
- An important aspect of optimizing micro- and optofluidic devices for lab on -a-chip systems is the ability to engineer materials properties including surface structure and charge to control wettability. Biocompatible ferroelectric lithium niobate (LN), which is well-known for acoustic and nonlinear optical applications, has recently found potential micro- and optofluidic applications. However, the tunable wettability of such substrates has yet to be explored in detail. Here, we show that the contact angle of LN substrates can be reproducibly tailored between similar to 7 degrees and similar to 421 degrees by controlling the surface topography and chemistry at the nano- and micrometer scale via ferroelectric domain and polarization engineering and polarization-directed photoassisted deposition of metallic nanostructures.
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| 8. |
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| 9. |
- Assanto, Gaetano, et al.
(författare)
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Spatial Solitons in 2D Lattices of a Nonlinear Nature
- 2008
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Ingår i: Optics and photonics news (Print). - : Optical Society of American (OSA). - 1047-6938 .- 1541-3721. ; 19:6, s. 29-32
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Tidskriftsartikel (refereegranskat)abstract
- Researchers have observed two-color optical solitons in a 2D parametric photonic lattices (PPLs) with hexagonal symmetry in lithium niobate. PPLs behave as uniform and homogenous dielectrics under weak excitation whereas, at high powers, they allow for the simultaneous quasi-phase-matching of several susceptibility processes. It has been observed that 2D PPLs support novel simulation space dynamics through twin-beam second-harmonic generation. In the symmetric configuration, solitons can form in an enhanced spectral range for confinement, while in the asymmetric cases, they can be steered by varying the input power and wave-length. Quadratic spatial solitons in planar nonlinear lattices unveils new opportunities for physics and also enable applications of self-trapped light beams, including the engineering of solitons states for analog signal processing and all-optical switching/routing in aperiodic lattices and quasi-crystals.
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| 10. |
- Baghban, Mohammad Amin, et al.
(författare)
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Bragg gratings in thin-film LiNbO3 waveguides
- 2017
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 25:26, s. 32323-32332
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Tidskriftsartikel (refereegranskat)abstract
- We design, fabricate and characterize sidewall corrugated Bragg gratings in a high confinement integrated optics lithium niobate platform, comprising submicrometric photonic wires, tapers and grating couplers to interface off-chip standard telecom optical fibers. We analyze the grating performance as band-rejection filter for TE-polarized signals in the telecom C-band, considering both rectangular and sinusoidal sidewall profiles, and demonstrate record extinction ratios as high as 27 dB and rejection bandwidths as narrow as 3 nm. The results show the potential for an efficient integration of novel photonic functionalities into low-footprint LiNbO3 nonlinear and electro-optical waveguide devices.
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| 11. |
- Baghban, Mohammad Amin, 1983-, et al.
(författare)
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Impact of longitudinal fields on second harmonic generation in lithium niobate nanopillars
- 2016
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Ingår i: APL Photonics. - : American Institute of Physics (AIP). - 2378-0967. ; 1:6
-
Tidskriftsartikel (refereegranskat)abstract
- An optimized focused ion beam process is used to fabricate micrometer-long LiNbO3 nanopillars with diameters varying between 150 and 325 nm. Polarimetric mappings of second harmonic generation from a wavelength of 850 nm demonstrate the ability to modify the polarization features of the nonlinearresponse through a fine adjustment of the pillar size. The effect is ascribed to the non-negligible contribution of the longitudinal fields associated with sub-wavelength light confinement in the LiNbO3nanopillars. The results also highlight the importance of a fine control over the nanopillar size in order to effectively engineer their nonlinear response.
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| 12. |
- Baghban, Mohammad Amin, 1983-
(författare)
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Integrated Nanophotonic Devices in Lithium Niobate
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lithium niobate (LN) is a ferroelectric crystal offering a broad transparency spectrum, together with excellent electro-optic and nonlinear optical properties. Thanks to them, LN is setting the standard for quantum optics and telecommunications in critical applications such as ultrafast modulation and frequency conversion. The development of a reliable nanophotonic platform in LN can be expected to effectively leverage all such appealing functionalities in compact and integrated formats and provide important and complementary functionalities to current silicon-photonics platforms.This thesis encompasses systematic and consistent efforts with the goal to achieve the key building blocks for a comprehensive integrated nanophotonic platform in LN. It involves work on the technology side, sustained and complemented by modelling and experiments, ultimately leading to the demonstration of a few novel devices.Ultrahigh field confinement in nanophotonic waveguides is accompanied by the appearance of non-negligible longitudinal components in the guided optical fields. By fabricating high-quality LN nanopillars and analyzing with theory and experiments their second harmonic generation (SHG) response, we provide evidence for the existence of longitudinal field components and demonstrate the possibility to reshape the SHG polar emission properties of these submicrometric waveguides by fine-tuning the nanopillar size.This thesis also presents a different technological approach, allowing the fabrication of photonic wires as small as 250 nm with lengths up to 1 cm on LN-on-insulator (LNOI), suitable for upscaling to photonic integrated circuit (PIC) architectures. By optimizing the fabrication process, the propagation losses of single-mode waveguides at telecom wavelengths on this platform were brought down from 76 to 1.13 dB/cm. Fine-pitch waveguide structuring was also successfully achieved, enabling LNOI-to-fiber grating couplers and waveguide Bragg gratings, the latter featuring record extinction ratios in LNOI (45 dB), comparable to the state of the art in silicon.The thesis involves also theoretical work on the design of photonic wires where the interplay between LN and waveguide birefringence is used to achieve polarization-insensitive operation for the fundamental guided modes.Finally, two demonstrators are provided for novel and emerging applications of LN to the life sciences, using LNOI surface-patterned templates for enhanced Raman spectroscopy and LN templates for controlled neuron growth and manipulation in microfluidic environments, respectively.
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| 13. |
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| 14. |
- Baghban, Mohammad Amin, 1983-, et al.
(författare)
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Phase-Shifted Bragg Grating Resonators in Thin-Film Lithium Niobate Waveguides
- 2019
-
Ingår i: 2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO).
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Konferensbidrag (refereegranskat)abstract
- We demonstrate narrowband integrated filters with 0.23 mm-long phase-shifted Bragg gratings in corrugated single-mode thin-film LiNbO3 photonic wires, achieving quality factors of 1.24x10(4) and extinction ratios up to 24 dB at telecom wavelengths.
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Balobaid, Laila, et al.
(författare)
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Direct shape control of photoreduced nanostructures on proton exchanged ferroelectric templates
- 2013
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 102:4, s. 042908-
-
Tidskriftsartikel (refereegranskat)abstract
- Photoreduction on a periodically proton exchanged ferroelectric crystal leads to the formation of periodic metallic nanostructures on the surface. By varying the depth of the proton exchange (PE) from 0.59 to 3.10 mu m in congruent lithium niobate crystals, the width of the lateral diffusion region formed by protons diffusing under the mask layer can be controlled. The resulting deposition occurs in the PE region with the shallowest PE depth and preferentially in the lateral diffusion region for greater PE depths. PE depth-control provides a route for the fabrication of complex metallic nanostructures with controlled dimensions on chemically patterned ferroelectric templates.
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| 19. |
- Balobaid, Laila, et al.
(författare)
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Photoreduction of metal nanostructures on periodically proton exchanged MgO-doped lithium niobate crystals
- 2013
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 103:18, s. 182904-
-
Tidskriftsartikel (refereegranskat)abstract
- Local reactivity on periodically proton exchanged lithium niobate (PPE: LN) surfaces is a promising route for the fabrication of regularly spaced nanostructures. Here, using MgO-doped PPE: LN templates, we investigate the influence of the doping on the nanostructure formation as a function of the proton exchange (PE) depth. The deposition is found to occur preferentially along the boundary between MgO-doped LN and the PE region when the PE depth is at least 1.73 mu m, however, for shallower depths, deposition occurs across the entire PE region. The results are found to be consistent with an increased photoconductivity of the MgO-doped LN.
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| 20. |
- Brambilla, E., et al.
(författare)
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Three and Four-Modes Parametric Processes in Hexagonally Poled Nonlinear Photonic Crystals
- 2018
-
Ingår i: OPTICS, PHOTONICS AND LASERS. - : INT FREQUENCY SENSOR ASSOC-IFSA. ; , s. 176-178
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 21. |
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| 22. |
- Bratfalean, Radu, et al.
(författare)
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Harmonic generation in a two-dimensional nonlinear quasi-crystal
- 2005
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 30:4, s. 424-426
-
Tidskriftsartikel (refereegranskat)abstract
- Second-harmonic generation in a two-dimensional nonlinear quasi-crystal is demonstrated for the first time to our knowledge. Temperature and wavelength tuning of the crystal reveal the uniformity of the pattern while angle tuning reveals the dense nature of the crystal's Fourier spectrum. These results compare well with theoretical predictions showing the excellent uniformity of the crystal and suggest that more-complicated nonlinear holograms should be possible.
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| 23. |
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| 24. |
- Carville, N. Craig, et al.
(författare)
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Biocompatibility of ferroelectric lithium niobate and the influence of polarization charge on osteoblast proliferation and function
- 2015
-
Ingår i: Journal of Biomedical Materials Research. Part A. - : John Wiley and Sons. - 1549-3296 .- 1552-4965. ; 103:8, s. 2540-2548
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the influence of substrate surface charge on in vitro osteoblast cell proliferation on ferroelectric lithium niobate (LN) crystal surfaces is investigated. LN has a spontaneous polarization along the z-axis and is thus characterized by positive and negative bound polarization charge at the +z and -z surfaces. Biocompatibility of LN was demonstrated via culturing and fluorescence imaging of MC3T3 osteoblast cells for up to 11 days. The cells showed enhanced proliferation rates and improved osteoblast function through mineral formation on the positively and negatively charged LN surfaces compared to electrostatically neutral x-cut LN and a glass cover slip control. These results highlight the potential of LN as a template for investigating the role of charge on cellular processes.
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| 25. |
- Carville, N. Craig, et al.
(författare)
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Biocompatible Gold Nanoparticle Arrays Photodeposited on Periodically Proton Exchanged Lithium Niobate
- 2016
-
Ingår i: ACS Biomaterials Science & Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 2:8, s. 1351-1356
-
Tidskriftsartikel (refereegranskat)abstract
- Photodeposition of silver nanoparticles onto chemically patterned lithium niobate having alternating lithium niobate and proton exchanged regions has been previously investigated. Here, the spatially defined photodeposition of gold nanoparticles onto periodically proton exchanged lithium niobate is demonstrated. It is shown that the location where the gold nanoparticles form can be tailored by altering the concentration of HAuCl4. This enables the possibility to sequentially deposit gold and silver in different locations to create bimetallic arrays. The cytocompatibility of photodeposited gold, silver, and bimetallic ferroelectric templates to osteoblast-like cells is also investigated. Gold samples provide significantly greater cell biocompatibility than silver samples. These results highlight a potential route for using photodeposited gold on lithium niobate as a template for applications in cellular biosensing.
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| 26. |
- Carville, N. C., et al.
(författare)
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Growth mechanism of photoreduced silver nanostructures on periodically proton exchanged lithium niobate : Time and concentration dependence
- 2013
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 113:18, s. 187212-1-187212-7
-
Tidskriftsartikel (refereegranskat)abstract
- Photodeposition of metallic nanostructures onto ferroelectric surfaces, which have been chemically patterned using a proton exchange process, has recently been demonstrated. By varying the molar concentration of the AgNO 3 solution and the illumination time, one can determine the initial nucleation sites, control the rate of nucleation and the height of silver nanostructures formed, and study the mechanisms by which these processes occurs. The nanoparticles are found to deposit preferentially in the boundary between ferroelectric and proton exchanged regions, in an area proton exchanged via lateral diffusion under the masking layer used for chemical patterning, consistent with our previous results. Using a short illumination time (3 min), we are able to determine that the initial nucleation of the silver nanostructure, having a width of 0.17 ± 0.02 μm and a height of 1.61 ± 0.98 nm, occurs near the edge of the reactive ion etched area within this lateral diffusion region. Over longer illumination times (15 min), we find that the silver deposition has spread to a width of 1.29 ± 0.06 μm, extending across the entire lateral diffusion region. We report that at a high molar concentration of AgNO3 (10-2 M), the amount of silver deposition for 5 min UV illumination is greater (2.88 ± 0.58 nm) compared to that at low (10-4 M) concentrations (0.78 ± 0.35 nm), however, this is not the case for longer time periods. With increasing illumination time (15 min), experiments at 10-4 M had greater overall deposition, 6.90 ± 1.52 nm, compared to 4.50 ± 0.76 nm at 10 -2 M. For longer exposure times (30 min) at 10-2 M, the nanostructure height is 4.72 ± 0.59 nm, suggesting a saturation in the nanostructure height. The results are discussed in terms of the electric double layer that forms at the crystal surface. There is an order of magnitude difference between the Debye lengths for 10-2 and 10-4 M solutions, i.e., 3.04 vs. 30.40 nm, which suggests the Debye length plays a role in the availability of Ag ions at the surface.
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| 27. |
- Carville, N. Craig, et al.
(författare)
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Influence of annealing on the photodeposition of silver on periodically poled lithium niobate
- 2016
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 119:5
-
Tidskriftsartikel (refereegranskat)abstract
- The preferential deposition of metal nanoparticles onto periodically poled lithium niobate surfaces, whereby photogenerated electrons accumulate in accordance with local electric fields and reduce metal ions from solution, is known to depend on the intensity and wavelength of the illumination and the concentration of the solution used. Here, it is shown that for identical deposition conditions (wavelength, intensity, concentration), post-poling annealing for 10 h at 200 degrees C modifies the surface reactivity through the reorientation of internal defect fields. Whereas silver nanoparticles deposit preferentially on the +z domains on unannealed crystals, the deposition occurs preferentially along 180 degrees domain walls for annealed crystals. In neither case is the deposition selective; limited deposition occurs also on the unannealed -z domain surface and on both annealed domain surfaces. The observed behavior is attributed to a relaxation of the poling-induced defect frustration mediated by Li+ ion mobility during annealing, which affects the accumulation of electrons, thereby changing the surface reactivity. The evolution of the defect field with temperature is corroborated using Raman spectroscopy.
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| 28. |
- Carville, N. Craig, et al.
(författare)
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Photoreduction of SERS-Active Metallic Nanostructures on Chemically Patterned Ferroelectric Crystals
- 2012
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 6:8, s. 7373-7380
-
Tidskriftsartikel (refereegranskat)abstract
- Photodeposition of metallic nanostructures onto ferroelectric surfaces is typically based on patterning local surface reactivity via electric field poling. Here, we demonstrate metal deposition onto substrates which have been chemically patterned via proton exchange (i.e., without polarization reversal). The chemical patterning provides the ability to tailor the electrostatic fields near the surface of lithium niobate crystals, and these engineered fields are used to fabricate metallic nanostructures. The effect of the proton exchange process on the piezoelectric and electrostatic properties of the surface is characterized using voltage-modulated atomic force microscopy techniques, which, combined with modeling of the electric fields at the surface of the crystal, reveal that the deposition occurs preferentially along the boundary between ferroelectric and proton-exchanged regions. The metallic nanostructures have been further functionalized with a target probe molecule, 4-aminothiophenol, from which surface-enhanced Raman scattering (SERS) signal is detected, demonstrating the suitability of chemically patterned ferroelectrics as SERS-active templates.
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| 29. |
- Cherifi-Hertel, S., et al.
(författare)
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Non-Ising and chiral ferroelectric domain walls revealed by nonlinear optical microscopy
- 2017
-
Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- The properties of ferroelectric domain walls can significantly differ from those of their parent material. Elucidating their internal structure is essential for the design of advanced devices exploiting nanoscale ferroicity and such localized functional properties. Here, we probe the internal structure of 180° ferroelectric domain walls in lead zirconate titanate (PZT) thin films and lithium tantalate bulk crystals by means of second-harmonic generation microscopy. In both systems, we detect a pronounced second-harmonic signal at the walls. Local polarimetry analysis of this signal combined with numerical modelling reveals the existence of a planar polarization within the walls, with Néel and Bloch-like configurations in PZT and lithium tantalate, respectively. Moreover, we find domain wall chirality reversal at line defects crossing lithium tantalate crystals. Our results demonstrate a clear deviation from the ideal Ising configuration that is traditionally expected in uniaxial ferroelectrics, corroborating recent theoretical predictions of a more complex, often chiral structure.
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| 30. |
- Conforti, Matteo, et al.
(författare)
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Broadband parametric processes in chi((2)) nonlinear photonic crystals
- 2014
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 39:12, s. 3457-3460
-
Tidskriftsartikel (refereegranskat)abstract
- We develop a general model, based on a (2 + 1)D unidirectional pulse propagation equation, for describing broadband noncollinear parametric interactions in 2D quadratic lattices. We apply it to the analysis of twin-beam optical parametric generation in hexagonally poled LiTaO3, gaining further insights into experimental observations.
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| 31. |
- Conforti, Matteo, et al.
(författare)
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Broadband parametric processes in quadratic nonlinear photonic crystals
- 2014
-
Ingår i: Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides, BGPP 2014. - Washington, D.C. : The Optical Society.
-
Konferensbidrag (refereegranskat)abstract
- We develop a general model, based on a (2+1)D unidirectional pulse propagation equation, for describing broadband noncollinear parametric interactions in two-dimensional quadratic lattices. We apply it to the analysis of twin-beam optical parametric generation in hexagonally poled LiTaO<inf>3</inf>, gaining further insights into experimental observations.
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| 32. |
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| 33. |
- Damm, S., et al.
(författare)
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Formation of ferroelectrically defined Ag nanoarray patterns
- 2014
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9781628410747
-
Konferensbidrag (refereegranskat)abstract
- In order to produce the most effective Ag nanoarrays for plasmon enhanced fluorescence and Raman scattering made using ferroelectric substrates, the optimum conditions for the creation of arrays must be identified. We study here Ag nanopattern arrays formed using ferroelectric lithography based on periodically proton exchanged (PPE) template methods. We examine different conditions in regard to deposition of Ag nanoparticles and analyze the plasmon enhanced signal from the resulting nanoarray. We apply FLIM (fluorescence lifetime imaging) to assess different Ag nanoarray preparation conditions on fluorescence emission from selected fluorphores. In addition, we apply Raman and luminescence spectroscopy with AFM (atomic force microscopy) to study the plasmon enhancement of luminescence and Raman from the Ag nanoarrays.
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| 34. |
- Damm, Signe, et al.
(författare)
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Plasmon enhanced Raman from Ag nanopatterns made using periodically poled lithium niobate and periodically proton exchanged template methods
- 2012
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 116:50, s. 26543-26550
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Tidskriftsartikel (refereegranskat)abstract
- We study Ag nanopattern arrays formed using ferroelectric lithography based on two separate approaches, i.e., periodically poled lithium niobate (PPLN) and periodically proton exchanged (PPE) template methods. We demonstrate that such nanoarrays are plasmon active. Raman spectroscopy was applied to study molecular probe 4-aminothiophenol (4-ABT) absorbed onto a silver nanostructured array. The observed Raman spectra show peaks arising from b2 modes, which occur for plasmon enhanced Raman from 4-ABT in place of a1 modes, which occur in normal Raman scattering. We demonstrate that the PPLN and PPE substrates possess different plasmonic properties with PPE creating a stronger SERS signal relative to PPLN substrates.
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| 35. |
- Damm, Signe, et al.
(författare)
-
Protein assemblies on ferroelectrically patterned microarrays of Ag nanoparticles
- 2017
-
Ingår i: Ferroelectrics (Print). - : TAYLOR & FRANCIS LTD. - 0015-0193 .- 1563-5112. ; 515:1, s. 141-148
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Tidskriftsartikel (refereegranskat)abstract
- Nano-bio interfaces play a significant role in assay device design and performance, here we study the use of a combined plasmonic and ferroelectric active substrate design for protein assemblies on a plasmon active array. We demonstrate that biotinylation and protein assemblies can bemade onmetal nanoparticles patterned on ferroelectric substrates. These results inturndemonstratethat ferroelectric substrates combined with active plasmonics is potentially applicable as substrates for biological assays.
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| 36. |
- Damm, S., et al.
(författare)
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SERS from Ag and Au nanoarrays made using photochemical patterning
- 2013
-
Ingår i: 2013 Conference on Lasers and Electro-Optics Europe and International Quantum Electronics Conference, CLEO/Europe-IQEC 2013. - : IEEE Computer Society. ; , s. 6801468-
-
Konferensbidrag (refereegranskat)abstract
- Metallic nanostructures made from 'coinage' metals such as silver or gold, yield plasmons when light creates a collective oscillation of the conduction electrons on the surface of the metal, creating a greatly enhanced electromagnetic field [1-3]. The specific properties of the plasmonic structures have been found to be greatly dependent on factors such as size, shape, and dielectric environment [1-3]. These properties have been exploited in a variety of plasmonic applications ranging from sensing to enhanced fluorescence [4].
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| 37. |
- Damm, Signe, et al.
(författare)
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Surface enhanced luminescence and Raman scattering from ferroelectrically defined Ag nanopatterned arrays
- 2013
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 103:8, s. 083105-
-
Tidskriftsartikel (refereegranskat)abstract
- Ag nanopatterned arrays prepared using periodically proton exchanged templates have been demonstrated to support surface enhanced luminescence. Fluorescence lifetime imaging reveals that luminescence intensity is greatest on Ag and that the lifetime of the molecular probe is reduced, in line with a surface enhanced luminescence mechanism. Studies establish that the substrate simultaneously supports surface enhanced luminescence and Raman scattering. Spatial dependence along the nanopatterned arrays shows <7% variation in Raman scattering signal intensity, offering high reproducibility for practical applications. Fluorophores emitting near the plasmon absorption maxima are enhanced 4-fold.
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| 38. |
- El Hassan, Ashraf, et al.
(författare)
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Coherent difference frequency generation in nonlinear photonic crystals
- 2023
-
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).
-
Konferensbidrag (refereegranskat)abstract
- Two-dimensional lattices of the optical nonlinearity implemented by periodic poling in X(2) materials afford additional degrees of freedom for enhanced gains in optical parametric generation [1-2] and the generation of multipartite photon entanglement in compact device formats [3]. So far all investigations have considered single-frequency excitation of the crystals in classical or quantum parametric downconversion regimes. However, the effects underpinned by the coherent coupling of multiple nonlinear resonances unique to 2D lattices, may be expected to further enlarge the spectrum of possibilities also in suitably seeded coherent parametric amplification and difference frequency generation (DFG) processes.
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| 39. |
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| 40. |
- Fergestad, Halvor, et al.
(författare)
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Engineered dispersion measurements in LiNbO3 nanophotonic wires
- 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).
-
Konferensbidrag (refereegranskat)abstract
- Dispersion engineering of waveguides in photonic integrated circuits (PIC) is a crucial design tool for tailoring nonlinear functionalities in the rapidly emerging thin film LiNbO3 (TFLN) platform, exemplified by frequency comb generation, soliton formation and broadband frequency conversion [1]. Experimentally, the dispersion of PIC structures is typically measured in terms of free-spectral range (FSR) variation in ring cavity configurations or propagation time delays in long waveguides under short pulse excitation [2], methods with their own limitations when it comes to measurements in straight and relatively short (< cm) waveguides, such as TFLN ones.
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| 41. |
- Fergestad, Halvor, et al.
(författare)
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Second Harmonic Generation and χχ(2) Cascading in Periodically Poled MgO:LiNbO3 Photonic Wires
- 2024
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Ingår i: The 25th European Conference on Integrated Optics - Proceedings of ECIO 2024. - : Springer Nature. ; , s. 145-148
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Konferensbidrag (refereegranskat)abstract
- We study second harmonic generation in LiNbO3 nanowaveguides, operated with sub-pJ pulses at 1424 nm in the picosecond regime generating 0.5 μW at 712 nm. Spectra recorded at both wavelengths provide evidence for enhanced χ(2) cascading effects.
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| 42. |
- Folli, V., et al.
(författare)
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Purely nonlinear disorder-induced localizations and their parametric amplification
- 2013
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 38:24, s. 5276-5279
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Tidskriftsartikel (refereegranskat)abstract
- We investigate spatial localization in a quadratic nonlinear medium in the presence of randomness. By means of numerical simulations and theoretical analyses we show that, in the down conversion regime, the transverse random modulation of the nonlinear susceptibility generates localizations of the fundamental wave that grow exponentially in propagation. The localization length is optically controlled by the pump intensity that determines the amplification rate. The results also apply to cubic nonlinearities.
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| 43. |
- Fu, Daiheng, et al.
(författare)
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Polarization coupling in thin film lithium niobate waveguide
- 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).
-
Konferensbidrag (refereegranskat)abstract
- Polarization control in photonic integrated circuit (PIC) waveguides is receiving broad attention for application in quantum systems and telecommunication [1]. Thin film lithium niobate (TFLN) is an ideal platform for polarization control applications due to its birefringence and electro-optic properties [2]. We observe polarization coupling between fundamental TE and TM modes in TFLN waveguides.
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| 44. |
- Gallo, Katia, et al.
(författare)
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Bidimensional Hexagonal Poling of LiNbO3 for Nonlinear Photonic Crystals and Quasi-Crystals
- 2006
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Ingår i: Ferroelectrics (Print). - : Informa UK Limited. - 0015-0193 .- 1563-5112. ; 340, s. 69-74
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Tidskriftsartikel (refereegranskat)abstract
- We report on the fabrication of bidimensional arrays of hexagonal domains with strictly periodic and quasi-periodic patterns for the implementation of nonlinear photonic crystals and quasi-crystals in z-cut congruent LiNbO3.
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| 45. |
- Gallo, Katia, et al.
(författare)
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Buried slab waveguides in LiNbO3 nonlinear photonic crystals
- 2005
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Ingår i: Proceedings of WFOPC 2005. - 0780389492 ; , s. 36-40
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Konferensbidrag (refereegranskat)abstract
- We present an efficient integrated device for SHG at telecom wavelengths in Hexagonally Poled LiNbO3, based on the reverse proton exchange waveguide technology. We discuss its nonlinear response in terms of power, wavelength and angle tunability and use the experimental SHG data to infer also information on the linear properties of the waveguide.
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| 46. |
- Gallo, Katia, et al.
(författare)
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Focus issue introduction : Advanced Solid-State Lasers (ASSL) 2015
- 2016
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 24:5, s. 5674-5682
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Tidskriftsartikel (refereegranskat)abstract
- The editors introduce the focus issue on "Advanced Solid-State Lasers (ASSL) 2015", which is based on the topics presented at a congress of the same name held in Berlin, Germany, from October 4 to October 9, 2015. This focus issue, jointly prepared by Optics Express and Optical Materials Express, includes 23 contributed papers (17 for Optics Express and 6 for Optical Materials Express) selected from the voluntary submissions from attendees who presented at the congress and have extended their work into complete research articles. We hope this focus issue offers a good snapshot of a variety of topical discussions held at the congress and will contribute to the further expansion of the associated research areas.
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| 47. |
- Gallo, Katia, et al.
(författare)
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Guided-wave second-harmonic generation in a LiNbO3 nonlinear photonic crystal
- 2006
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 31:9, s. 1232-1234
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate twin-beam second-harmonic generation from telecommunications wavelengths in an optimized buried reverse proton exchanged planar waveguide made in 2D hexagonally poled LiNbO3. Experiments carried out with a nanosecond narrow-bandwidth, high-power fiber source thoroughly explored the response of the nonlinear photonic crystal device in terms of its power, wavelength, and angle tunability.
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| 48. |
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| 49. |
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| 50. |
- Gallo, Katia
(författare)
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Nonlinear wave dynamics in 2D periodically poled waveguides
- 2009
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Ingår i: 2009 IEEE/LEOS WINTER TOPICALS MEETING SERIES (WTM 2009). - NEW YORK : IEEE. - 9781424426102 ; , s. 162-163
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Konferensbidrag (refereegranskat)abstract
- An overview of recent results on spatial solitons in purely nonlinear 2D lattices is presented. Theory and experiments highlight new possibilities for multicolour soliton excitation and control via planar nonlinear structures in periodically poled materials.
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