FOTONICA - Grup de Recerca de Fotònica
http://hdl.handle.net/2117/3270
Sat, 25 Feb 2017 09:32:04 GMT2017-02-25T09:32:04ZA 3D printed toolbox for opto-mechanical components
http://hdl.handle.net/2117/100862
A 3D printed toolbox for opto-mechanical components
Salazar Serrano, Luis Jose; Pérez Torres, Juan; Valencia, Alejandra
In this article we present the development of a set of opto-mechanical components (a kinematic mount, a translation stage and an integrating sphere) that can be easily built using a 3D printer based on Fused Filament Fabrication (FFF) and parts that can be found in any hardware store. Here we provide a brief description of the 3D models used and some details on the fabrication process. Moreover, with the help of three simple experimental setups, we evaluate the performance of the opto-mechanical components developed by doing a quantitative comparison with its commercial counterparts. Our results indicate that the components fabricated are highly customizable, low-cost, require a short time to be fabricated and surprisingly, offer a performance that compares favorably with respect to low-end commercial alternatives.
Fri, 10 Feb 2017 14:28:16 GMThttp://hdl.handle.net/2117/1008622017-02-10T14:28:16ZSalazar Serrano, Luis JosePérez Torres, JuanValencia, AlejandraIn this article we present the development of a set of opto-mechanical components (a kinematic mount, a translation stage and an integrating sphere) that can be easily built using a 3D printer based on Fused Filament Fabrication (FFF) and parts that can be found in any hardware store. Here we provide a brief description of the 3D models used and some details on the fabrication process. Moreover, with the help of three simple experimental setups, we evaluate the performance of the opto-mechanical components developed by doing a quantitative comparison with its commercial counterparts. Our results indicate that the components fabricated are highly customizable, low-cost, require a short time to be fabricated and surprisingly, offer a performance that compares favorably with respect to low-end commercial alternatives.A measure of flow vorticity with twisted beams of light
http://hdl.handle.net/2117/100606
A measure of flow vorticity with twisted beams of light
Belmonte Molina, Aniceto; Rosales Guzmán, Carmelo; Pérez Torres, Juan
The measurement of vorticity, a parameter providing local measurements of
rotation at every point in a flow, would greatly assist research fields as diverse as biology microfluidics, complex motions in the oceanic and atmospheric boundary layers, and wake turbulence on fluid aerodynamics. However, the precise measurement of flow vorticity is difficult. Here, we devise an experiment in which the local vorticity of a flow can be estimated by probing the fluid with Laguerre-Gauss beams, optical beams that show an azimuthal phase variation that is the origin of its characteristic non-zero orbital angular momentum. The key point is to make use of the transversal Doppler effect of the returned signal that depends only on the azimuthal component of the flow velocity along the ringshaped
observation beam. We found from a detailed analysis of the experimental method
that probing the fluid with LG beams is an effective and simple sensing technique capable to produce accurate estimates of flow vorticity.
Tue, 07 Feb 2017 09:01:35 GMThttp://hdl.handle.net/2117/1006062017-02-07T09:01:35ZBelmonte Molina, AnicetoRosales Guzmán, CarmeloPérez Torres, JuanThe measurement of vorticity, a parameter providing local measurements of
rotation at every point in a flow, would greatly assist research fields as diverse as biology microfluidics, complex motions in the oceanic and atmospheric boundary layers, and wake turbulence on fluid aerodynamics. However, the precise measurement of flow vorticity is difficult. Here, we devise an experiment in which the local vorticity of a flow can be estimated by probing the fluid with Laguerre-Gauss beams, optical beams that show an azimuthal phase variation that is the origin of its characteristic non-zero orbital angular momentum. The key point is to make use of the transversal Doppler effect of the returned signal that depends only on the azimuthal component of the flow velocity along the ringshaped
observation beam. We found from a detailed analysis of the experimental method
that probing the fluid with LG beams is an effective and simple sensing technique capable to produce accurate estimates of flow vorticity.Vector mixed-gap surface solitons
http://hdl.handle.net/2117/100241
Vector mixed-gap surface solitons
Kartashov, Yaroslav V.; Ye, F; Torner Sabata, Lluís
We elucidate the properties of mixed-gap vector surface solitons supported by the interface between a uniform medium and an optical lattice imprinted in a Kerr-type nonlinear media. The components of such mixed-gap solitons emerge from different gaps of lattice spectrum and their mutual trapping results in the formation of stable vector states. The unstable soliton component is stabilized by the cross-coupling with the stable component. We show that vector mixed-gap surface solitons exhibit a new combination of properties of vectorial surface waves and gap solitons.
Fri, 27 Jan 2017 17:28:04 GMThttp://hdl.handle.net/2117/1002412017-01-27T17:28:04ZKartashov, Yaroslav V.Ye, FTorner Sabata, LluísWe elucidate the properties of mixed-gap vector surface solitons supported by the interface between a uniform medium and an optical lattice imprinted in a Kerr-type nonlinear media. The components of such mixed-gap solitons emerge from different gaps of lattice spectrum and their mutual trapping results in the formation of stable vector states. The unstable soliton component is stabilized by the cross-coupling with the stable component. We show that vector mixed-gap surface solitons exhibit a new combination of properties of vectorial surface waves and gap solitons.Sensitivity study of the microwave spiralimetric imaging
http://hdl.handle.net/2117/100239
Sensitivity study of the microwave spiralimetric imaging
Jofre Roca, Lluís; Blanch Boris, Sebastián; Cardama Aznar, Ángel; Rius Casals, Juan Manuel; Torner Sabata, Lluís
The use of the spiral modes-electromagnetically related to the orbital momentum of the photons- at microwave frequencies for imaging purposes is studied and some preliminary numerical and experimental results for basic canonical geometries are presented and discussed
Fri, 27 Jan 2017 17:19:19 GMThttp://hdl.handle.net/2117/1002392017-01-27T17:19:19ZJofre Roca, LluísBlanch Boris, SebastiánCardama Aznar, ÁngelRius Casals, Juan ManuelTorner Sabata, LluísThe use of the spiral modes-electromagnetically related to the orbital momentum of the photons- at microwave frequencies for imaging purposes is studied and some preliminary numerical and experimental results for basic canonical geometries are presented and discussedObservation of Dyakonov surface waves
http://hdl.handle.net/2117/100238
Observation of Dyakonov surface waves
Takayama, Osamu; Crasovan, I; Artigas García, David; Torner Sabata, Lluís
Summary form only given. A special type of surface wave was predicted by M. I. Dyakonov in 1988. Such waves exist under special conditions at the interface of transparent anisotropic materials, and hens they are lossless. This surface waves require at least one of the two media to be an anisotropic medium, either biaxial or positive uniaxial, and various configurations have been investigated. In the case of the interface of a biaxial anisotropic medium with refractive indices nx, ny and nz, and an isotropic medium with refractive indices nc, surface waves form only when the refractive indices fulfill the condition n1 > nc > n2 > n3, where n1 = max (nx ; ny ; nz), n3 = min (nx ; ny ; nz) and, n2 is in between n1 and n3,. For a positive uniaxial medium, the condition becomes nc > nc > no, where no and nc are the ordinary and extraordinary refractive indices, respectively. When such a condition is fulfilled, hybrid surface waves containing both ordinary and extraordinary field components propagate within a narrow angular band, Deltathetas, with respect to the crystal optical axis. The allowed propagation angles are referred to as the angular existence domain. The condition is difficult to meet with standard available crystals, making difficult the observation of Dyakonov waves . Here we report on their first observation. Our experiment was conducted in a structure based on a potassium titanyl phosphate (KTP) crystal at lambda = 632.8 nm and index matching liquids with refractive indices that satisfy the given condition. We used a modified Otto-Kretchmann configuration which is composed of a prism, an isotropic liquid layer, and KTP substrate to excite the surface wave at the liquid-KTP interface. Surface wave excitation was detected by imaging the reflected beam. We conducted experiments with five different index matching liquids, and measured the cutoff angle, thetasmax, where the reflected peak associated with the Dyakonov surface wave disappears. The paper illustrates a potential application of Dyakonov surface waves as high sensitive refractive index sensors. The influence of the different structural parameters, such as the thickness of the isotropic layer as on the excitation is discussed.
Fri, 27 Jan 2017 17:18:13 GMThttp://hdl.handle.net/2117/1002382017-01-27T17:18:13ZTakayama, OsamuCrasovan, IArtigas García, DavidTorner Sabata, LluísSummary form only given. A special type of surface wave was predicted by M. I. Dyakonov in 1988. Such waves exist under special conditions at the interface of transparent anisotropic materials, and hens they are lossless. This surface waves require at least one of the two media to be an anisotropic medium, either biaxial or positive uniaxial, and various configurations have been investigated. In the case of the interface of a biaxial anisotropic medium with refractive indices nx, ny and nz, and an isotropic medium with refractive indices nc, surface waves form only when the refractive indices fulfill the condition n1 > nc > n2 > n3, where n1 = max (nx ; ny ; nz), n3 = min (nx ; ny ; nz) and, n2 is in between n1 and n3,. For a positive uniaxial medium, the condition becomes nc > nc > no, where no and nc are the ordinary and extraordinary refractive indices, respectively. When such a condition is fulfilled, hybrid surface waves containing both ordinary and extraordinary field components propagate within a narrow angular band, Deltathetas, with respect to the crystal optical axis. The allowed propagation angles are referred to as the angular existence domain. The condition is difficult to meet with standard available crystals, making difficult the observation of Dyakonov waves . Here we report on their first observation. Our experiment was conducted in a structure based on a potassium titanyl phosphate (KTP) crystal at lambda = 632.8 nm and index matching liquids with refractive indices that satisfy the given condition. We used a modified Otto-Kretchmann configuration which is composed of a prism, an isotropic liquid layer, and KTP substrate to excite the surface wave at the liquid-KTP interface. Surface wave excitation was detected by imaging the reflected beam. We conducted experiments with five different index matching liquids, and measured the cutoff angle, thetasmax, where the reflected peak associated with the Dyakonov surface wave disappears. The paper illustrates a potential application of Dyakonov surface waves as high sensitive refractive index sensors. The influence of the different structural parameters, such as the thickness of the isotropic layer as on the excitation is discussed.Management of the angular momentum of light: preparation of photons in multidimensional vector states of angular momentum
http://hdl.handle.net/2117/100066
Management of the angular momentum of light: preparation of photons in multidimensional vector states of angular momentum
Molina Terriza, Gabriel; Pérez Torres, Juan; Torner Sabata, Lluís
We put forward schemes to prepare photons in multidimensional vector states of orbital angular momentum. We show realizable light distributions that yield prescribed states with finite or infinite normal modes. In particular, we show that suitable light vortex pancakes allow the add-drop of specific vector projections. We suggest that such photons might allow the generation of engineered quNits in multidimensional quantum information systems.
Wed, 25 Jan 2017 17:12:09 GMThttp://hdl.handle.net/2117/1000662017-01-25T17:12:09ZMolina Terriza, GabrielPérez Torres, JuanTorner Sabata, LluísWe put forward schemes to prepare photons in multidimensional vector states of orbital angular momentum. We show realizable light distributions that yield prescribed states with finite or infinite normal modes. In particular, we show that suitable light vortex pancakes allow the add-drop of specific vector projections. We suggest that such photons might allow the generation of engineered quNits in multidimensional quantum information systems.Ultrabroadband biphotons generated via chirped quasi-phase-matched optical parametric down-conversion
http://hdl.handle.net/2117/100059
Ultrabroadband biphotons generated via chirped quasi-phase-matched optical parametric down-conversion
Nasr, M B; Carrasco, S; Saleh, B E A; Sergienko, A V; Teich, M C; Pérez Torres, Juan; Torner Sabata, Lluís; Hum, D S; Fejer, M M
We generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion (SPDC) in quasi-phase-matched nonlinear gratings that have a linearly chirped wave vector. By using these ultrabroadband biphotons (300-nm bandwidth), we measure the narrowest Hong-Ou-Mandel dip to date, having a full width at half maximum of 7.1 fs. This enables the generation of a high flux of nonoverlapping biphotons with ultrabroad bandwidth, thereby promoting the use of SPDC light in many nonclassical applications.
Wed, 25 Jan 2017 16:38:41 GMThttp://hdl.handle.net/2117/1000592017-01-25T16:38:41ZNasr, M BCarrasco, SSaleh, B E ASergienko, A VTeich, M CPérez Torres, JuanTorner Sabata, LluísHum, D SFejer, M MWe generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion (SPDC) in quasi-phase-matched nonlinear gratings that have a linearly chirped wave vector. By using these ultrabroadband biphotons (300-nm bandwidth), we measure the narrowest Hong-Ou-Mandel dip to date, having a full width at half maximum of 7.1 fs. This enables the generation of a high flux of nonoverlapping biphotons with ultrabroad bandwidth, thereby promoting the use of SPDC light in many nonclassical applications.Soliton excitation in waveguide arrays with an effective intermediate dimensionality
http://hdl.handle.net/2117/100058
Soliton excitation in waveguide arrays with an effective intermediate dimensionality
Szameit, Alexander; Kartashov, Yaroslav V.; Dreisow, Felix; Heinrich, Matthias; Pertsch, T; Nolte, Stefan; Tunnermann, A F Lederer; Vysloukh, Victor A.; Lederer, F.; Torner Sabata, Lluís
We reveal and observe experimentally significant modifications undertaken by discrete solitons in waveguide lattices upon the continuous transformation of the lattice structure from one-dimensional to two-dimensional. Light evolution and soliton excitation in arrays with a gradually increasing number of rows are investigated, yielding solitons with an effective reduced dimensionality residing at the edge and in the bulk of the lattice.
Wed, 25 Jan 2017 16:36:15 GMThttp://hdl.handle.net/2117/1000582017-01-25T16:36:15ZSzameit, AlexanderKartashov, Yaroslav V.Dreisow, FelixHeinrich, MatthiasPertsch, TNolte, StefanTunnermann, A F LedererVysloukh, Victor A.Lederer, F.Torner Sabata, LluísWe reveal and observe experimentally significant modifications undertaken by discrete solitons in waveguide lattices upon the continuous transformation of the lattice structure from one-dimensional to two-dimensional. Light evolution and soliton excitation in arrays with a gradually increasing number of rows are investigated, yielding solitons with an effective reduced dimensionality residing at the edge and in the bulk of the lattice.Inhibition of light tunneling in waveguide arrays
http://hdl.handle.net/2117/100055
Inhibition of light tunneling in waveguide arrays
Szameit, Alexander; Kartashov, Yaroslav V.; Dreisow, Felix; Heinrich, Matthias; Pertsch, T; Nolte, Stefan; Tunnermann, A; Vysloukh, Victor A.; Lederer, F; Torner Sabata, Lluís
We report the observation of almost perfect light tunneling inhibition at the edge and inside laser-written waveguide arrays due to band collapse. When the refractive index of the guiding channels is harmonically modulated along the propagation direction and out-of-phase in adjacent guides, light is trapped in the excited waveguide over a long distance due to resonances. The phenomenon can be used for tuning the localization threshold power.
Wed, 25 Jan 2017 16:31:49 GMThttp://hdl.handle.net/2117/1000552017-01-25T16:31:49ZSzameit, AlexanderKartashov, Yaroslav V.Dreisow, FelixHeinrich, MatthiasPertsch, TNolte, StefanTunnermann, AVysloukh, Victor A.Lederer, FTorner Sabata, LluísWe report the observation of almost perfect light tunneling inhibition at the edge and inside laser-written waveguide arrays due to band collapse. When the refractive index of the guiding channels is harmonically modulated along the propagation direction and out-of-phase in adjacent guides, light is trapped in the excited waveguide over a long distance due to resonances. The phenomenon can be used for tuning the localization threshold power.Observation of two-dimensional spatial solitary waves in a ¿ (2) medium
http://hdl.handle.net/2117/99961
Observation of two-dimensional spatial solitary waves in a ¿ (2) medium
Torruellas, William; Stegeman, George; Torner Sabata, Lluís
Cascaded second order nonlinear processes offer a new range of opportunities. Indeed we have shown that under near phase matching conditions, the associated nonlinear phase distortion to the fundamental wave depletion follows a linear dependence with the optical field strength and not the optical intensity. Equivalently in such a regime cascaded self focusing effects are inherently equivalent to a saturated intensity dependent phase distortion, hence multi-dimensional soliton like second order nonlinear optical media
Tue, 24 Jan 2017 15:50:03 GMThttp://hdl.handle.net/2117/999612017-01-24T15:50:03ZTorruellas, WilliamStegeman, GeorgeTorner Sabata, LluísCascaded second order nonlinear processes offer a new range of opportunities. Indeed we have shown that under near phase matching conditions, the associated nonlinear phase distortion to the fundamental wave depletion follows a linear dependence with the optical field strength and not the optical intensity. Equivalently in such a regime cascaded self focusing effects are inherently equivalent to a saturated intensity dependent phase distortion, hence multi-dimensional soliton like second order nonlinear optical media