Optical anisotropy induced at five different wavelengths in azopolymer thin films: Kinetics and spectral dependence

Nedelchev, Lian; Ivanov, Deyan; Blagoeva, Blaga; Nazarova, Dimana

doi:10.1016/j.jphotochem.2019.02.009

Cited by 21 publications

(7 citation statements)

References 33 publications

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“…Instead, we introduced a single parameter, the response time τ DE , which allowed for easy and clear comparison between the various samples and recording conditions. This defined as the time required to reach 80% of DE max by analogy with the birefringence response time τ ∆n , which was used in previous publications [38,42]. The values of τ DE for the kinetics in Figure 4 are in the range 700-1200 s. They are considerably higher than the birefringence response times for the same samples-τ ∆n = 30-40 s, which can be calculated from the data, published in Ref.…”

Section: Resultsmentioning

confidence: 93%

“…Polarization holographic gratings were recorded using a 442 nm He-Cd gas laser (IK4171I G, Kimmon Koha) as a coherent light source. This wavelength was selected, as our earlier studies had shown, as it produces the highest photoinduced birefringence in PAZO [38]. A classical polarization holographic optical setup was used [39], as shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

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Tunable Polarization and Surface Relief Holographic Gratings in Azopolymer Nanocomposites with Incorporated Goethite (α-FeOOH) Nanorods

et al. 2021

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We employ two approaches to tune the properties of concurrently inscribed volume polarization and surface relief gratings in nanocomposite thin films containing the azopolymer PAZO (poly[1-4-(3-carboxy-4-hydrophenylazo)benzensulfonamido]-1,2-ethanediyl, sodium salt]) and goethite (α-FeOOH) nanorods. The first one is applied on the stage of sample preparation by varying the concentration of the goethite nanorods from 0% to 15%. Then, different angles between the recording beams are set in the holographic scheme, which allow us to obtain gratings with spatial periods in the range from 0.86 to 2.51 µm. Surface relief modulation close to 300 nm is achieved as well as total diffraction efficiency in the ±1 diffracted orders of more than 50%. The influence of the incorporated goethite nanorods on the properties of both volume birefringence and the surface relief grating are discussed.

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Section: Resultsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Tunable Polarization and Surface Relief Holographic Gratings in Azopolymer Nanocomposites with Incorporated Goethite (α-FeOOH) Nanorods

et al. 2021

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“…3(a) is 560 s, and for the PAZO/water sample in Fig. 3(b) it is 520 s. This response time is much higher than the birefringence response time at this wavelength and laser intensity 26 , which is 15 s. This implies that the volume polarization grating is formed in the initial stage of recording and the rest of the recording time is required for the formation of the surface relief grating. The experimental data for all samples prepared and recorded within this experiment are summarized in Table 1 below.…”

Section: Resultsmentioning

confidence: 89%

“…A He-Cd gas laser (Kimmon Koha) emmiting at 442 nm was used as recording laser. This wavelength was selected, as according to our recent study 26 , highest birefringence (Δn ≈ 0.08) is obtained in PAZO at 442 nm. Furthermore, this laser provides sufficient coherence length required for polarization holography.…”

Section: Recording Of the Polarization Holographic Gratingsmentioning

confidence: 99%

Diffraction efficiency of polarization holographic gratings recorded in azopolymer thin films coated using different solvents

Blagoeva

Nedelchev

Mateev

et al. 2020

Photosensitive Materials and Their Applications

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We present a study of the diffraction efficiencies of polarization holographic gratings recorded in thin films of the azopolymer PAZO (poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl, sodium salt]). Two series of layers have been prepared using two different solvents-distilled water and methanol. The gratings are inscribed by two plain waves with orthogonal circular polarizations (left and right circular) from a He-Cd gas laser (442 nm) at recording angle 20°, corresponding to grating period 1.3 µm. Higher diffraction efficiency is obtained for the thin film samples spin-coated from the methanol solution for thicknesses below 600 nm. Diffraction efficiency higher than 27% was achieved, as well as surface relief height more than 500 nm.

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“…Over the past two decades, the PAZO polymer has found numerous applications: layer-by-layer (LbL) films containing PAZO prepared and used for second harmonic generation [ 5 , 6 ], studies of photoisomerization [ 7 ] and photoinduced birefringence [ 8 , 9 , 10 , 11 ]. Recently, an optimal recording wavelength for thin films of PAZO was determined to be λ ~ 442 nm, whereby the highest birefringence Δ n max = 0.081 was obtained for this wavelength [ 12 ]. In addition, the photoinduced birefringence in PAZO has exceptionally high thermal stability to almost 300 °C [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Dispersion Model Characterization of PAZO Azopolymer Thin Films over the Entire Transmittance Spectrum Measured in the UV/VIS/NIR Spectral Region

et al. 2022

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Notwithstanding the significant optical applicability of PAZO polymer films, there are no accurate data about their optical characteristics. To remedy this shortcoming, in this study three PAZO polymer thin films are characterized, with dissimilar thicknesses, on glass substrates using only one UV/VIS/NIR transmittance spectrum T(λ) per sample and an original hybrid dispersion model (HDM). HDM is based on the Tauc‒Lorentz model, the new amorphous dispersion formula, the Tauc‒Lorentz‒Urbach model of Foldyna and the Tauc‒Lorentz‒Urbach model of Rodriguez. HDM with two oscillators is employed in characterizations of the PAZO polymer films in the range [300, 2500] nm, whereby the root-mean-square deviation (RMSD) of the fitted transmittance spectrum with respect to T(λ) does not exceed 1.6 × 10−3. Decreasing RMSD by 2.3% to 94.4% is demonstrated by employing HDM compared with the above mentioned four popular dispersion models, for each one of the studied films. HDM is applicable to amorphous films independent of their thickness as well as to cases of non-transparent substrate.

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Optical anisotropy induced at five different wavelengths in azopolymer thin films: Kinetics and spectral dependence

Cited by 21 publications

References 33 publications

Tunable Polarization and Surface Relief Holographic Gratings in Azopolymer Nanocomposites with Incorporated Goethite (α-FeOOH) Nanorods

Tunable Polarization and Surface Relief Holographic Gratings in Azopolymer Nanocomposites with Incorporated Goethite (α-FeOOH) Nanorods

Diffraction efficiency of polarization holographic gratings recorded in azopolymer thin films coated using different solvents

Hybrid Dispersion Model Characterization of PAZO Azopolymer Thin Films over the Entire Transmittance Spectrum Measured in the UV/VIS/NIR Spectral Region

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