Abstract:Photochromic diarylethenes with D–A structure are good candidates in holography thanks to their very large modulation of the complex refractive index.
“…Chalcogenide glasses 28 are interesting, but the application in large size element is not easy. Photochromic materials have been studied quite a long and decent ∆n were reported [29][30][31] . On the other hand, there is not any chemical amplification, they cannot be used in the visible and they are reversible; therefore, the application is almost impossible for making VPGHs.…”
Volume Phase Holographic Gratings (VPHGs) are optical dispersing element widely used in astronomical spectrographs. In the last years, the availability of high performance photopolymers allowed for the development of innovative approaches to produce these dispersing elements. The key activities that have been carried out are: i) a production process based on photopolymeric holographic materials (in particular Bayfol ® HX by COVESTRO AG) was defined; ii) high quality VPHGs > 170 mm in diameter were manufactured; iii) innovative configurations to increase the dispersion/spectral range were implemented. The effectiveness of these activities is confirmed by the fact that more than 10 devices are mounted on observing facilities and several more are in development or planned. In this paper, we present the VPH technology based on photopolymers.
“…Chalcogenide glasses 28 are interesting, but the application in large size element is not easy. Photochromic materials have been studied quite a long and decent ∆n were reported [29][30][31] . On the other hand, there is not any chemical amplification, they cannot be used in the visible and they are reversible; therefore, the application is almost impossible for making VPGHs.…”
Volume Phase Holographic Gratings (VPHGs) are optical dispersing element widely used in astronomical spectrographs. In the last years, the availability of high performance photopolymers allowed for the development of innovative approaches to produce these dispersing elements. The key activities that have been carried out are: i) a production process based on photopolymeric holographic materials (in particular Bayfol ® HX by COVESTRO AG) was defined; ii) high quality VPHGs > 170 mm in diameter were manufactured; iii) innovative configurations to increase the dispersion/spectral range were implemented. The effectiveness of these activities is confirmed by the fact that more than 10 devices are mounted on observing facilities and several more are in development or planned. In this paper, we present the VPH technology based on photopolymers.
“…Instead, the Raman spectra of the closed form are dominated by strong and distinctive Raman transitions assigned to the skeletal motion of the CC bonds coupled with the delocalized and highly polarizable p-electrons. 67,70 Since the photochromic compounds become fully p-conjugated while passing from the O to the C form, 71,72 their change in the Raman spectra (Fig. 11(A) vs.…”
Herein, we investigate structure-property relationships in a new series of benzothiazole based unsymmetrical hexafluorocyclopentene dithienylethenes (DTEs) and compare the results with the known facts for symmetric diarylethenes (DAEs). We reveal high...
“…S5 †). 64,65 The quantum efficiency for the conversion of TPY-DTE-GO to TPY-DTE-GC and vice versa was calculated to be 60% and 46%, respectively (Fig. S10 †).…”
Section: Synthesis Characterization and Applications Of Photochromism...mentioning
A lanthanide based photochromic coordination polymer gel (pcCPG) material has been developed which showed photomodulated colour change based on pcFRET and has the potential to be employed for decoding secret information.
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