Winfried H. G. Horsthuis

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.

Two‐photon absorption and third‐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′‐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.

Comparison of quasi‐phase‐matching geometries for second‐harmonic generation in poled polymer channel waveguides at 1.5 μm

We have investigated three different quasi‐phase‐matching approaches to second‐harmonic generation (SHG) in DANS (4‐dimethylamino‐4′‐nitrostilbene) poled polymer channel waveguides at 1.5 μm. 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.

Simple measuring method for electro-optic coefficients in poled polymer waveguides

A simple measuring technique for the linear electro‐optic coefficients in electro‐optic waveguides is described. The method is based on the direct evaluation of synchronous angle measurements obtained by prism coupling. No waveguide or electrode patterning is required. A model has been developed in order to simulate the relation between change in synchronous angle and applied electric field across the electro‐optic waveguide. The measured values of the electro‐optic coefficients in poled polymer waveguides are reported.

Recent Developtents In Optically Nonlinear Polymers And Related Electro-Optic Devices

Side chain polymers, containing hyperpolarizable moieties as pendant groups, have been applied as optically nonlinear materials. Electro-optic properties have been induced via electric field poling of nultilayer structures incorporating the nonlinear polymers. For a poling field strength of 156 Wpm, the obtained i r33 coefficient was equal to 28 pn/V at the wavelength of 1.3 pm, which is close to r33 = 32 of the inorganic single crystal lithium niobate. Low loss mcnomode charnel waveguides (< 1 dB/cm @ 1.3 μm wavelength) have been realized in the optically nonlinear polymer nultilayers. Tunable Fabry-Perot etalons, monamode phase and intensity modulators and monomode Mach-Zehnder interferameters, have been made and tested; their performances will be discussed. Owing to their considerable electro-optic coefficients and attractive processing properties, polymers are becoming serious alternatives for the currently often applied lithium niobate.

Large, nonresonant, intensity dependent refractive index of 4‐dialkylamino‐4’‐nitro‐diphenyl‐polyene side chain polymers in waveguides

We report the experimental evaluation of the intensity‐dependent index of refraction of a new class of third order nonlinear materials, side chain polymers containing 4‐dialkylamino‐4’‐nitro‐stilbene and 4‐dialkylamino‐4’‐nitro‐diphenylbutadiene as side groups. The measurements, based on nonlinear grating coupling into planar waveguides with 30 ps pulses at 1.064 μm, showed large electronic nonresonant n2 Kerr coefficients.

The cubic susceptibility dispersion of Alkoxy-nitro-stilbene (MONS) and Di-alkyl-amino-nitro-stilbene (DANS) side chain substituted polymers : comparison with the two-level model

The complex cubic susceptibility dispersion of side chain polymers containing 4‐dialkylamino‐4’‐nitro‐stilbene, 4‐alkoxy‐4’‐nitro‐stilbene as their side groups has been measured in the range of 0.953 μm to 1.904 μm with third harmonic generation. A two level model is compared to the experimental data in the three‐photon‐resonance spectral region. Microscopic local field cascading was found to give an important contribution to the third order susceptibility. Nonlinear susceptibilities comparable to those of fully conjugated backbone polymers are obtained.

Third order nonlinearity of 4‐dialkylamino‐4’nitro‐stilbene waveguides at 1319 nm

The intensity dependent optical properties of 4‐dialkylamino‐4’nitro‐stilbene polymer channel waveguides were measured at 1319 nm with a pulse modulated Mach–Zehnder interferometer to be n2=0.8×10−13 cm2/W and β2<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.

Optically nonlinear polymeric switches and modulators

Side chain polyrrers containing hyperpolarizable noieties as the periant groups have been applied as optically ncrilinear traterials to produce polyxreric integrat1 electro-optical devices . Phase nixiulators, intisity nixiulators (1ch-Zebzx1er interferaiters) aixi optical 2*2 sce switches ( 2*2 directixa1 nixie couplers) have been uncle . Driving voltages as 1ci as 2 Volts (V ) have been obtain1 for a 24 nm active 1gth çkmse ncdulator; 4.4 Volts (V ) for a 14 inn active 1angthch-Zebrx1er interferarter, ath 9 Volts for a 14 nm active length directionI node ccupler. Intisity nixiulation ratios of about -23 dB atti -17 dB have been derived for the intensity nixiulator atd nixie ccxipling switch, respectively. The device properties , theni.l arxi electrical stabilities , etc. will be discussed. The results obtained shcw that optically txnlinear polyiTers are attractive caixlidates for the realizaticzi of polyireric integrated electro-optical devices. In additicn, several passive veguiding devices have beai nnde.

Strong field, in‐plane poling for nonlinear optical devices in highly nonlinear side chain polymers

The conditions essential for high field, in‐plane poling were investigated for nonlinear optical (NLO), planar devices with 4‐dimethylamino‐4’‐nitrostilbene (DANS) side‐chain polymers. Applied poling field as large as 370 V/μm were achieved before breakdown occurred and a nonlinearity of d22=153 pm/V at 1064 nm (near resonant) was obtained with stable poling at 300 V/μm.