Quasi-Phase Matched Surface Emitting Second Harmonic Generation In Poled Polymer Waveguides

Quasi-phase matched (QPM) surface emitting second harmonic generation was demonstrated with nonlinear/linear multilayer waveguides in poled polymer based devices. The nonlinear/linear multilayer film was fabricated with a 4-dimethylamino-4\u27-nitrostilbene (DANS) side chain polymer and a cross-linkable clear polymer. Large efficiency improvement was observed with a combination of QPM and strong field parallel poling

Two-Photon Absorption Of Di-Alkyl-Amino-Nitro-Stilbene Side-Chain Polymer

The two photon absorption spectrum has been measured in the 780–1600 nm range for a di‐alkyl‐amino‐nitro‐stilbene side‐chain polymer. A single two photon peak centered at 920 nm is observed with a peak two photon coefficient of 5.5 cm/GW. Bleaching via two photon absorption at this wavelength is investigated by measuring a refractive index change after an intensive exposure

Size-Selective Personal Air Sampling: A New Approach Using Porous Foams

Simultaneous sampling of three dust fractions (inhalable, thoracic, respirable) has been achieved using porous polyurethane foams, which serve both as selecting and sampling media. The particle penetration was measured in laboratory tests. Foam geometries were predicted using a semi-empirical model. Prototype samplers were constructed based on the IOM and GSP inhalable personal samplers. Weighing and chemical analysis procedures were checked for the foam

Comparison Of Quasi-Phase-Matching Geometries For Second-Harmonic Generation In Poled Polymer Channel Waveguides At 1.5 Mu M

We have investigated three different quasi-phase-matching approaches to second-harmonic generation (SHG) in DANS (4-dimethylamino-4\u27-nitrostilbene) poled polymer channel waveguides at 1.5 mu m. Periodic photobleaching and periodically poled electrodes deposited directly on the film produced unacceptably high propagation losses. However, periodic electrodes on the substrate gave low losses and useful SHG

3Rd-Order Nonlinearity Of 4-Dialkylamino-4\u27Nitro-Stilbene Wave-Guides At 1319 Nm

The intensity dependent optical properties of 4-dialkylamino-4\u27nitro-stilbene polymer channel waveguides were measured at 1319 nm with a pulse modulated Mach-Zehnder interferometer to be n2 = 0.8 x 10(-13) cm2/W and beta2 \u3c 0.08 cm/GW. This material is promising for all-optical switching at 1319 nm because it satisfies both the W and T figures of merit

2Nd-Harmonic Generation By Counter Propagating Beams In 4-Dimethylamino-4\u27-Nitrostilbene Side-Chain Polymer Channel Wave-Guides

We demonstrate surface emitted second harmonic generation due to mixing of counter propagating waves in in-plane poled, low loss, channel waveguides of 4-dimethylamino-4\u27-nitrostilbene (DANS) side-chain polymers. Single film DANS side-chain polymer waveguides yield high conversion efficiency devices

2-Photon Absorption And 3Rd-Harmonic Generation Of Di-Alkyl-Amino-Nitro-Stilbene (Dans) - A Joint Experimental And Theoretical-Study

The one- and two-photon optical absorption spectra as well as the frequency dependent third-harmonic generation response of a side-chain polymer containing 4-dialkylamino-4\u27-nitro-stilbene (DANS) as its side group have been measured over a wide range of frequency. A three-state model, based on an intermediate neglect of differential overlap/multireference double-configuration interaction description of the excited states, provides a coherent picture of the dynamic response of DANS, but fails in reproducing the red shift observed when going from the linear to the nonlinear absorption spectra; including vibronic coupling within the Franck-Condon approximation improves the fit

UV continuum emission and diagnostics of hydrogen-containing non-equilibrium plasmas

For the first time the emission of the radiative dissociation continuum of the hydrogen molecule ($a^{3}\Sigma_{g}^{+} \to b^{3}\Sigma_{u}^{+}$ electronic transition) is proposed to be used as a source of information for the spectroscopic diagnostics of non-equilibrium plasmas. The detailed analysis of excitation-deactivation kinetics, rate constants of various collisional and radiative transitions and fitting procedures made it possible to develop two new methods of diagnostics of: (1) the ground $X^{1}\Sigma_{g}^{+}$ state vibrational temperature $T_{\text{vib}}$ from the relative intensity distribution, and (2) the rate of electron impact dissociation (d[\mbox{H_{2}}]/dt)_{\text{diss}} from the absolute intensity of the continuum. A known method of determination of $T_{\text{vib}}$ from relative intensities of Fulcher-$\alpha$ bands was seriously corrected and simplified due to the revision of $d \to a$ transition probabilities and cross sections of $d \gets X$ electron impact excitation. General considerations are illustrated with examples of experiments in pure hydrogen capillary-arc and H$_{2}$+Ar microwave discharges.Comment: REVTeX, 25 pages + 12 figures + 9 tables. Phys. Rev. E, eprint replaced because of resubmission to journal after referee's 2nd repor