Search results for "polarization."
showing 10 items of 1842 documents
Self-Trapped Localized Modes in Photonic Crystal Fibers
2002
We demonstrate the existence of self-trapped localized modes in photonic crystal fibers. We analyze these solutions in terms of the parameters of the photonic crystal cladding and the nonlinear coupling.
Modulational instability processes in optical isotropic fibers under dual-frequency pumping
2001
Experiments are presented showing that under dual-frequency, circular polarization pumping, a host modulational instability processes can be generated in a single isotropic fiber, by carefully tuning the frequency spacing between the pumps.
Two-Color Single Hybrid Plasmonic Nanoemitters with Real Time Switchable Dominant Emission Wavelength
2015
International audience; We demonstrate two-color nanoemitters that enable the selection of the dominant emitting wavelength by varying the polarization of excitation light. The nanoemitters were fabricated via surface plasmon-triggered two-photon polymerization. By using two polymerizable solutions with different quantum dots, emitters of different colors can be positioned selectively in different orientations in the close vicinity of the metal nanoparticles. The dominant emission wavelength of the metal/polymer anisotropic hybrid nanoemitter thus can be selected by altering the incident polarization.
An all-organic steroid–D–π-A modular design drives ferroelectricity in supramolecular solids and nano-architectures at RT
2011
Confluence of a modular design approach and self-assembly with a 'steroid-D-π-A' module generates spontaneous polarization in solids and for the first time in nano-architectures constituted from organogels, at room temperature (RT).
Polymer based tuneable photonic crystals
2007
We report on the fabrication and characterization of photonic crystal slab waveguide resonators which contain a nanostructured second-order nonlinear optical polymer. The combination of a photonic crystal resonator realized in a second-order nonlinear optical polymer allowed the detection of electro-optical modulation of light with a sub-1-V sensitivity. Furthermore we report on the synthesis of novel nonlinear optical polymers with large second-order hyperpolarizability and improved glass transition temperature. The polymer slab waveguide is micro patterned by means of electron-beam lithography and reactive ion etching. The photonic crystal slab-based resonator consisted of a square lattic…
Improved noncontact optical sensor for detection of glucose concentration and indication of dehydration level.
2014
The ability to extract different bio-medical parameters from one single wristwatch device can be very applicable. The wearable device that is presented in this paper is based on two optical approaches. The first is the extraction and separation of remote vibration sources and the second is the rotation of linearly polarized light by certain materials exposed to magnetic fields. The technique is based on tracking of temporal changes of reflected secondary speckles produced in the wrist when being illuminated by a laser beam. Change in skin’s temporal vibration profile together with change in the magnetic medium that is generated by time varied glucose concentration caused these temporal chan…
Two-dimensional photonic-crystal microwave waveguide
2003
This paper reports on the use of 2D photonic crystals to design microwave waveguides. The waveguide consists of a periodic arrangement of holes, with a square or rectangular cross section, that extends along the waveguide with a central defect defined by the absence of a hole. The theoretical analysis of such a structure is based on a biorthogonal-basis method and provides a full-vector description of the modes guided by the defect. Our results show that such a waveguide can be designed to support only one mode at any operating frequency. This mode is a polarization doublet whose dispersion is controlled by the geometrical parameters, thus permitting the design of a novel polarization-maint…
Efficient unidirectional polarization-controlled excitation of surface plasmon polaritons
2014
Efficient excitation of surface plasmon polaritons (SPPs) remains one of the most challenging issues in areas of plasmonics related to information communication technologies. In particular, combining high SPP excitation efficiency and acceptance of any polarization of incident light appeared to be impossible to attain due to the polarized nature of SPPs. Here we demonstrate plasmonic couplers that represent arrays of gap SPP resonators producing upon reflection two orthogonal phase gradients in respective linear polarizations of incident radiation. These couplers are thereby capable of efficiently converting incident radiation with arbitrary polarization into SPPs that propagate in orthogon…
High-harmonic km-long self-pulsed Raman fiber laser
2011
Raman all-fiber lasers have attracted considerable interest during the past two decades due to their convenient use and extended wavelength coverage when compared to rare-earth-doped fiber lasers. Still, little is known about their potential as pulsed laser sources. Mode locked Raman fiber lasers have been demonstrated quite recently [1,2], as well as harmonic mode-locking with a record of 500,000 intra-cavity pulses in a dissipative four-wave mixing configuration using a fiber Bragg grating [3].
Improved active fiber-based retroreflector with intensity stabilization and a polarization monitor for the near UV.
2021
We present an improved active fiber-based retroreflector (AFR) providing high-quality wavefront-retracing anti-parallel laser beams in the near UV. We use our improved AFR for first-order Doppler-shift suppression in precision spectroscopy of atomic hydrogen, but our setup can be adapted to other applications where wavefront-retracing beams with defined laser polarization are important. We demonstrate how weak aberrations produced by the fiber collimator may remain unobserved in the intensity of the collimated beam but limit the performance of the AFR. Our general results on characterizing these aberrations with a caustic measurement can be applied to any system where a collimated high-qual…