The surface relief grating formation in As2S3 and As40S15Se45 films under laser wavelengths λ = 491, 532, 561, 594 and 633 nm light influence was examined. The studies of spectral dependence of photoinduced birefringence and its development during the holographic recording in studied chalcogenide films showed that photoinduced birefringence plays an important role in SRG formation process.

In this work the methods for improvement of recording parameters of surface relief holograms are studied using approximate to 3 mu m thick azo-epoxy AAB: BADGE films. Our interest was pointed towards the possibility of experimentally checking the conditions which are more favourable for increasing the diffraction efficiency of surface relief holograms by self-enhancement and by assisting light illumination so contributing to a decrease of recording light exposure dose and recording time for initial grating. The first step of the experiment was to choose the appropriate polarization relationship for the light beams involved in the process. Subsequently, we studied the grating behaviour in light exposure with one of the recording beam when second one is closed, i.e. self-enhancement, was tested. The influence of assisting light during recording and self-enhancement was examined.

Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2017/7 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged”

Azo-epoxy resist is promising material for direct holographic recording due to good photosensitivity and possibility to modify structure of molecule during synthesis - obtained polymer polymerization index easily can be changed by varying curing temperature and curing time. Produced photoresist had properties similar to low-weight molecular glasses. In this work 4-Aminoazobenze, Disperse Orange 2 and epoxy resin bisphenol A diglycidyl ether were used. Surface relief grating formation by direct holographic method was performed in obtained resists. Surface relief grating post-recording self-enhancement process was investigated. It allows to increase a depth of surface relief grating after holographic recording, using physical method - uniform light illumination. It decreases time and required exposure for recording, making holographic recording more effective because grating formation is less affected by vibrations and noises.

Relief surface formation as a result of light irradiation is one important property of chalcogenide glasses which gives rise of number of applications. Understanding the nature of the process is an essential step towards optimization of the relief images obtained. This work depicts the mechanisms for surface relief grating formation in Ge-Se thin films exposed to diffracted light. A dependence on the period of the illumination source is revealed, which correlates with the composition of the thin film material. Raman spectroscopy, Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscopy (AFM) were used to analyze the films. The results point towards a dual effect of light irradiation leading to mass transport and structural changes, which results in a surface relief formation. Copyright © VBRI Press.

The effect of acid-base modification of 44(4-(bis(5,5,5-Triphenylpentyl) amino) phenyl) diazenyl) benzoic acid in context of the sensitivity to the polarization holographic recording was studied. Diethylamine and acetic acid as the modifiers were added to the amino acid solution immediately prior to application by spin-coating method. The relief formation by photoindused mass-transport in the films under the action of lasers with wavelengths of 405 and 532 nm was examined.

In this work the direct one step formation of surface relief gratings (SRG) in azo-epoxy polymer films during holographic recording was studied. In this material azo-compound is covalently attached to epoxy forming polymer. The main advantages of azo-epoxy polymers are simple and cheap synthesis, low polymerization degree, thus the photo-induced mass transport process has been facilitated. The dependence of SRG formation efficiency in AAB: BADGE films on sample preparation conditions, film content, recording parameters and possibility of reversible recording and SRG self-enhancement process was studied.

The direct formation of surface relief gratings (SRG) in amorphous chalcogenide and low molecular weight azo-benzene containing organic glass films during holographic recording was studied. It has been shown that the course of SRG growth curves can be divided in three development stages: an induction period of photo-induced birefringence, linear growing of SRGs and saturation of SRG inscription process. The influence of the photo-induced birefringence on the relief formation process in amorphous As-S and As-S-Se films was evaluated and compared with the measurements on azo-benzene containing organic glass films. It was shown that the saturation of SRG formation depends on the surface tension of recording material.

Glassy SiO2 is the basic material for optical fibre waveguides and manufacturing-induced Cl impurities reduce their transparency in UV spectral range. This work reports in-depth study/spectroscopic parameters of the near-infrared (1.23 eV) low-temperature photo-luminescence (PL) of interstitial Cl-2 molecules in SiO2. The zero-phonon line position was estimated at 2.075 eV on the basis of anharmonicity of Cl-2 PL vibronic data. The vibronic sub-bands are broadened by coupling to phonons and by an additional contribution from the glassy disorder. The Huang. Rhys factor is approximate to 13. The PL decay time is between 1 and 10 ms in the temperature range 100 K-13 K and can be reproduced by 3 exponents. Cl-2 PL retains relatively high quantum yield and its characteristic structured shape, when the temperature is increased from 13 K to the liquid nitrogen temperature. This allows using it conveniently as a high-sensitivity diagnostic tool for detecting Cl-2 impurities in optical fibre waveguides. Time-resolved measurements of optical fibre waveguides indicate that the lower detection limit is below 10(10) Cl-2/cm(3).

Glassy SiO2 is the basic material for optical fibre waveguides and manufacturing-induced Cl impurities reduce their transparency in UV spectral range. This work reports in-depth study/spectroscopic parameters of the near-infrared (1.23 eV) low-temperature photo-luminescence (PL) of interstitial Cl2 molecules in SiO2. The zero-phonon line position was estimated at 2.075 eV on the basis of anharmonicity of Cl2 PL vibronic data. The vibronic sub-bands are broadened by coupling to phonons and by an additional contribution from the glassy disorder. The Huang‒Rhys factor is ≈13. The PL decay time is between 1 and 10 ms in the temperature range 100 K‒13 K and can be reproduced by 3 exponents. Cl2 PL retains relatively high quantum yield and its characteristic structured shape, when the temperature is increased from 13 K to the liquid nitrogen temperature. This allows using it conveniently as a high-sensitivity diagnostic tool for detecting Cl2 impurities in optical fibre waveguides. Time-resolved measurements of optical fibre waveguides indicate that the lower detection limit is below 1010 Cl2/cm3.

The studies of direct holographic recording of the surface relief gratings (SRG) on amorphous As40Se60-xSex (0 <= x <= 60) thin films are presented. The gratings were created by orthogonally +/- 45 degrees linearly polarized light beams of various wavelengths (lambda = 473 - 650 nm). The surface structure of the relief gratings was investigated by atomic force microscopy. The influence of laser beam wavelength and spatial frequency of the gratings (grating period Lambda) on the surface relief grating formation efficiency was examined.

Tento clanek se zabýva studiem přimeho holografickeho zaznamu povrchových difrakcnich mřižek v amorfnich tenkých vrstvach systemu As40Se60-xSex (0 <= x <= 60). Mřižky byly připraveny ortogonalně (+/- 45 stupňů) linearně polarizovanými paprsky různých vlnových delek (lambda = 473 - 650 nm). Povrchova struktura připravených mřižek byla studovana metodou atomarni silove mikroskopie. Dale byl studovan vliv vlnove delky laseroveho paprsku a prostorove frekvence mřižky (periody mřižky Lambda) na ucinnost formovani povrchove difrakcni mřižky.

The study of direct recording of the surface relief gratings on amorphous chalcogenide thin films is presented. Direct patterning was performed on As2S3 by 532 nm wavelength laser light using a 10 square m optical slit. The evolution of a surface relief in dependence from the recording time and polarization has been investigated in detail. It has been shown that the formation of surface relief grating closely depends on the superposition of electric field of the gradient beam and supplemental beam, thus the mass transfer can be directed both ways - towards or away from the electric field intensity gradient.

In this paper we present the synthesis and optical properties of amorphous low molecular compound 4-4(4(bis(5,5,5-Triphenylpentyl)amino)phenyl)diazenyl)benzoic acid. The surface relief gratings formation by polarization holography method on these thin films (thicknesses are 200-1700 nm) was shown. The dependence of the surface relief modulation on various parameters: recording exposure dose, the polarization state of the recording beams, the grating period and the film thickness of the material was demonstrated. Values of surface tension at the air-film before and after irradiation of the substance by polarized radiation were measured. The efficiency of surface relief formation in different medium was compared. The possibility of practical application of 4-((4-(bis(5,5,5-Triphenylpentyl)amino)phenyl)diazenyl)benzoic acid in the holography as a non-etching photoresist was showed. (C) 2015 Elsevier B.V. All rights reserved.

In this report an all-optical photo-induced formation of surface relief gratings is shown. For the surface patterning of As2S3 and As4S1.5Se4.5 films a direct holographic recording setup with a 532nm wavelength Nd: YAG CW laser light was used. Our investigations have shown that the light-induced mass transfer process strongly depends on the material itself and on the polarization of the light. It has been shown that an electric field intensity gradient has to be obtained to achieve a direct patterning. The evolution of a surface relief in relation to recording parameters and thickness of the sample has been investigated in detail.

Azobenzene containing compounds are among light polarization sensitive materials - the moieties may align relative to the electric field vector of light, leading to anisotropy and birefringence in the sample Another phenomenon which can be observed in azo compounds under influence of light is macroscopic movement of the material. In this work photoinduced processes in low molecular weight organic glass - bis-azobenzene containing compound K-D-2 were experimentally studied. Birefringence was induced with linearly polarized laser light (473, 532 and 635 nm) and measured at 633 nm wavelength. Polarization holography with recording beam configuration +45 degrees/-45 degrees was used to induce mass motion. Dependence of the surface relief depth on the recording laser wavelength in the visible spectrum (375 - 671 nm) was obtained. Formation of the SRG was observed with all used wavelengths and high birefringence values were obtained. Certain correlation between the absorption of the wavelength and photoinduced mass transport and birefringence is yet to be confirmed.

One of the used methods to induce mass motion on the surface of azopolymer films is holographic recording using laser wavelength corresponding to the absorption band of the azo compound. The sinusoidal light interference pattern on the surface of the sample leads to a sinusoidal surface patterning - a stable surface relief grating (SRG). As confirmed by atomic force microscopy (AFM), these gratings are found to be very large, with depth up to hundreds of nanometres and they diffract light very efficiently. In this work azobenzene containing low molecular weight organic glass K-RJ-8 was experimentally studied. The compound absorbs at the visible spectrum, holographic recording in this range using different polarization states of the recording beams was done. Diffraction efficiency was measured during the recording of the SRG. The relationship between formation of SRG and photoinduced birefringence is discussed.

The studies of direct holographic recording of the surface relief gratings on amorphous As 40 S 60-x Se x thin films are presented. These gratings were created upon exposure to polarized laser beams of various wavelengths (λ = 473 - 650 nm). The orthogonally ±45° linearly polarized light beams were used for recording. The surface structure of the relief gratings was investigated by atomic force microscopy. The influence of laser beam wavelength and spatial frequency of the gratings recorded (grating period ?) on the surface relief gratings formation for every composition was examined.

In this work surface relief direct formation during holographic recording in poly (Disperse Red 1 – methacrylate) films was studied. In this material azo-dye Disperse Red 1 is covalently attached to the main polymeric chain making lateral mass transport in the film caused by a presence of light electric field direction modulation very fast and effective. Surface relief grating formation process was induced by 532 nm laser. Read-out was performed by 660 nm diode laser. Diffraction efficiencies kinetics dependence on polarization state of reading and recording beams was studied. Surface relief depth on the films was measured by AFM. Deep surface relief gratings were obtained in Poly (Disperse Red 1 – methacrylate). Films relief can exceed the initial thickness of the sample more than three times. Fabrication of such surface relief gratings is fast and easy. They can find their application in data storage, electro-optical devices, telecommunication.

The demand for lower cost surface-relief based optical instruments such as gratingbased resonators or filters for waveguides, diffractometers, spectrometers etc is one of the main driving forces for the investigation of direct light-induced relief formation. The most common techniques for fabricating and investigating these surface-relief gratings involve an interferometric or holographic recording setup. In this paper the evolution of surface relief in dependence from the recording time and polarization has been investigated in detail.