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Abstract
In the present research, a new class of bromine-containing photo-thermo-refractive (PTR) glass in which the UV irradiation and subsequent heat treatment cause the precipitation of silver nanoparticles with a shell consisting of silver bromides is developed and studied. The growth of AgBr nanocrystals is shown to lead to a local positive refractive index change (refractive index of crystallized glassy area is higher than one of non-crystalline) in the UV-irradiated area against the unirradiated area up to 800 ppm. Based on this effect, samples of a volume Bragg grating and a waveguide structure have been recorded.
© 2017 Optical Society of America
Corrections
12 June 2017: Typographical corrections were made to the display equations in Section 3.
1. Introduction
Today, classical fluoride photo-thermo-refractive (PTR) glasses are among the most promising materials for the photonic applications. These glasses are widely used for recording the volume Bragg gratings [1] and pictorial holograms [2], constructing lasers and optical amplifiers [3–5], and also creating luminescent elements [6], fluidic devices [7], and waveguide structures [8].
The standard PTR glass is a photosensitive multi-component sodium–zinc–aluminosilicate glass containing fluorine (6 mol.%) and bromine (0.5 mol.%) and doped with small amounts of additives that are responsible for the photo-thermo-induced precipitation of silver nanoparticles and sodium fluoride crystals (cerium 0.01 mol.%, antimony– 0.01 mol.%, and silver 0.01 mol.% – see, for example [9–11]). The selective UV irradiation into the Ce3+ absorption band (310 nm) of these glass results in the formation of neutral silver molecular clusters (SMC) [11] that provide an intense and broadband luminescence in the visible and IR ranges [12]. The subsequent heat treatment(HT) of UV-irradiated PTR glass near the glass transition temperature (Tg) leads to the silver nanoparticle formation [11]. Following thermal treatment of these glass at temperatures above Tg results in the silver bromide shell growth on a silver nanoparticle [9] and then in the sedimentation of sodium fluoride cone on it [11,13]. In the end of photo-thermo-induced crystallization process the precipitation of sodium fluoride results in negative refractive index change (RIC) only in the UV-irradiated area [14,15]. In more details photo-thermo-induced crystallization process have been described in [16,17]
In our research we have synthesized bromide PTR glass with positive refractive index change during photo-thermo-induced crystallization and studied their spectral properties, refractive indices and crystalline phase precipitation mechanism for the first time.
2. Experimental
We developed bromide PTR glass based on Na2O-ZnO-Al2O3-SiO2-NaF system with reduced fluorine concentration and variable batch concentration of Br (0-1.5 mol.%) doped with photosensitizer such as CeO2 (0.01 mol.%), Sb2O3 (0.05 mol.%), and Ag2O (0.1 mol.%). For glass synthesis, the high purity reagents were used. The glass synthesis had been conducted in Gero electric furnace with air atmosphere using the platinum crucibles, the melts being homogenized with platinum stirrer. It should be noted that, during the synthesis, Ce and Sb partly change their valence states from IV to III and from III to V, respectively [18,19]. After synthesis glass samples were annealed at 520°C with further cooling in accord with a pre-set program (~0.3°C/min). The glass transition temperature was measured with differential scanning calorimeter STA 449 F1 Jupiter (Netzsch), the Tg magnitude being found to be 513 ± 2°C for all bromine concentrations. Due to high volatility of bromine in glass, all glass compositions had been controlled with the X-ray fluorescence analysis using ARL PERFORM'X (Thermo Scientific).
Samples to be investigated were prepared in the form of polished plane-parallel plates 0.1 - 1 mm thick. For all samples, the refractive index was measured using Abbe-type (IRF-454 2BM) refractometer at λ ≈590 nm (nd) with an error of 0.0002.
For glass photoactivating, a mercury lamp (EFOS Novacure N2001) was used. The 290-410 nm spectral range was cut off with optical filters. The digital interface of this lamp allows for supporting a constant power (19 W/cm2) and controlling the UV irradiation dose via the irradiation time variation in the 5-500 s limits. The HT of the samples was conducted at 550°C for 3 hours in a muffle furnace (Nabertherm) with program control.
The optical density spectra of the PTR glass samples were recorded in the 200–800 and 200-2500 nm spectral regions using Lambda 650 and Lambda 900 (Perkin–Elmer) spectrophotometers, respectively. Measurement of the absorption spectra under liquid nitrogen temperature were conducted using Lambda 650 spectrometer and cryostat (Specac). Also, the XRD analysis of the samples was performed using Ultima IV (Rigacu) X-ray diffractometer.
3. Results and discussion
Figure 1 demonstrates the absorption spectra of untreated PTR glass differing in the bromine concentration. As seen, the occurrence of relatively low bromine concentration (up to 0.7 mol.%) in glass composition does not affect its absorption spectrum and, in particular, generates no additional absorption in the region of Ce3+ -related band involved into the glass photoactivation. On the other hand, glass with higher bromine concentration (1 and 1.5 mol.%) show some increased absorption in the UV area near Ce3+, Ce4+, Sb5+ etc.- related bands [20,21].
Fig. 1 Absorption spectra of untreated PTR glass differing in the bromine concentration (mol.%): (1) 0, (2) 0.7, (3) 1.0, (4) 1.5 An inset shows bromine concentration remained in PTR glass according to XRF analysis vs. its as-batch concentration and the photos of untreated bromide PTR glass differing in the bromine concentration (mol.%): (1) 0, (2) 0.7, (3) 1.0, (4)
An inset in Fig. 1 presents the dependence of bromine concentration remained in glass according to XRF analysis on its as-batch concentration. As seen, the bromine concentration in glass by analysis is less, for all samples, by 50-60% than the as-batch one. The dependence shown can be linearly approximated. Therefore, further we will refer to the as-batch bromine concentration.
Also, the incorporation of bromine affects the PTR glass refractive index (nd). An increase in the Br concentration leads to a linear increase in its refractive index from 1.5009 to 1.5029 for bromine-free glass and glass containing 1.5 mol.% Br, respectively (Fig. 8), which is in agreement with reference data for silica glasses [22,23]
The effect of the UV irradiation on the absorption spectra of PTR glass is illustrated at Fig. 2. As seen, an increase in the UV irradiation dose results in shifting the UV edge of strong absorption and intensifying the absorption in the 300 – 500 nm region that corresponds to the locations of SMC absorption bands as in case of chloride PTR glasses [17]. It is visible clearly that with increase of UV irradiation dose Ce3+ absorption band, that locates around 309 nm, is disappeared due to Ce4+ ions formation, that has absorption peak near UV edge [20]. Also, shift of absorption is mostly caused by electron trapping by Sb5+ ions with formation of (Sb5+)- complexes with absorption band near 260 nm [21]. An inset in Fig. 2 shows the difference absorption spectra of UV-irradiated PTR glass containing 0.7 mol.% Br. As shown on the inset, an increment in the UV exposure time results in increasing the absorption in the 240-500 nm region. It can be seen that prolonged UV irradiation leads to the significant increase of the absorption around 240 and 260 nm, these bands may be referred to Ce4+ ions and (Sb5+)- charged complexes respectively, number of which increasing during UV irradiation. The absorption band around 260 nm is rather broad and responsible for the absorption in the 250-300 nm range. The absorption in the 330-500 nm was attributed to be due to SMC such as Ag2, Ag3, Ag2+, etc [12]. The amplification of absorption bands due to the charged antimony and SMC centers is caused by increasing their numbers during the Ce3+ ion photoionization by mercury lamp radiation in agreement with mechanism described in [24]. Notably, as seen from Fig. 2 and its inset, the long-lasting UV irradiation (50, 500 s) results in a reduction in the intensities of SMC-related absorption bands. This decrease in absorption can be caused by photo destruction of SMC by mercury lamp radiation, the radiation range of the latter matching the SMC absorption band.
Fig. 2 Effect of UV irradiation dose on the absorption spectra of PTR glass containing 0.7 mol.% Br. The exposure duration that sets a dose is (1) 0, (2) 1, (3) 5, (4) 50, and (5) 500 s. An inset presents the difference absorption spectra of glass containing 0.7 mol.% Br for various UV exposure durations, the durations being (1) 1, (2) 5, (3) 50, and (4) 500 s.
Clearly seen that bromide PTR glass have photoactivation mechanism that is similar to classical PTR glass [11,16].
At the first stage, the trivalent cerium ion under the effect of the UV irradiation donates an electron, thus increasing its own valency in accordance with the following reaction:
Released photoelectrons can be trapped partially by silver ions with subsequent neutral silver atom and molecular cluster formation (Ag0, Ag20, Ag2+, Ag32+) but most photoelectrons are trapped by antimony according to the following reaction:
It is important to note that an incorporation of bromine in glass composition (0.25 mol.%) leads to intensification (about 0.5 cm1) of absorption in the 330-500 nm region covering the SMC absorption bands. In addition, further increase of Br concentration has much smaller effect on the absorption spectra of UV irradiated glasses, that is different from the behavior of previously studied chloride PTR glasses [17].
One can presume that incorporation of bromine in PTR glass composition should leads to an increase in the amount of inhomogeneities in the glass bulk that occur in the form of breakdowns of the glass network [22]. In this case, the formation of neutral SMCs should become more favorable and, consequently, their amount should increase, but, as were mentioned earlier, increasing of bromine concentration has no significant effect on the absorption spectra of silver molecular clusters, and evidently has low effect on their number. Also, negatively charged bromine ions in glass can attach to the positively charged SMC, thus forming Agn-Br molecular clusters. The possibility of forming Agn–Br (n = 2–7) stable molecular clusters was demonstrated in [25] by numerical simulation.
The heat treatment of UV-irradiated specimens at temperatures higher than glass transition one results in the formation of silver nanoparticles that manifest themselves in the surface plasmon resonance absorption band located in the 420 - 490 nm region.
Thermal treatment of PTR glass with no bromine leads to precipitation of silver nanoparticles which manifest themselves via surface plasmon resonance, with the maximum located at 420 nm (Fig. 4), which is in agreement with data for chloride PTR glasses [17]. On the Fig. 3 the effects of UV irradiation, with varied doses, and subsequent heat treatment on the absorption spectra of PTR glasses containing Br in amounts 0.25 – 0.7 mol.% is shown. As seen from Fig. 3(a) the incorporation of 0.25 mol.% of bromine results in plasmon resonance band shift by 35nm up to 455nm; furthermore, when bromine concentration increases from 0.25 to 0.5 mol.% the absorption maximum shifts to 488 nm.
Fig. 3 Absorption spectra PTR of UV-irradiated and heat-treated PTR glass for various UV exposure durations. (a) Spectra of PTR glass containing 0.25 mol.% Br, the exposure durations being (1) 0, (2) 1, (3) 5, (4) 50, and (5) 500 s. (b) Spectra of PTR glass containing 0.5 mol.% Br, the exposure durations being (1) 0, (2) 1, (3) 5, (4) 50, and (5) 500 s. An inset shows the photos of the glass samples containing 0.5 mol.% Br for the exposure durations of (1) 1, (2) 5, (3) 50, and (4) 500 s.
As shown in [26], firstly this shift of plasmon resonance band can be caused by local refractive index increase in an area surrounding the silver nanoparticle, and also by thickening of this area. Figure 4 shows the effect of bromine concentration on the absorption spectra of UV irradiated (for 50s) and heat treated PTR glass. It can be seen that the addition of bromine to PTR glass (up to 0.5 mol.%) firstly leads to plasmon resonance band intensification and shifts its maximum toward to the grater wavelengths; at the same time further increase of bromine content (0.7 – 1.5 mol.%) results in plasmon resonance band decrease and shifts short-wave absorption edge towards to the greater wavelengths. Calculating of silver nanoparticle size using Mie theory [27,28]) revealed that increasing of bromine content leads to silver nanoparticles size reduction of (inset Fig. 4, black dots). Extrapolation of size calculations through all studied bromine concentration gives us average diameter less than 1,4 nm for silver nanoparticles in PTR glass with 1 and 1.5 mol.% of Br, also according to absorption spectra PTR glass with such small nanoparticles have no plasmon resonance absorption peak, which is in agreement with literature data for small silver nanoparticles in glass [29]
Fig. 4 Absorption spectra of UV-irradiated (for 50 s) and heat-treated PTR glass with various bromine concentrations (mol.%) such as (1) 0, (2) 0.25, (3) 0.5, (4) 0.7, (5) 1.0, (6) 1.5 An inset shows the effect of bromine concentration on the average size of silver nanoparticles (NP); calculated using Mie theory [27,28]. Black dots – calculated size of silver nanoparticles for different bromine concentration. Red line – extrapolation through out all bromine concentrations.
Also it can be seen that thermal treatment of UV irradiated for 5 s and longer bromide PTR glass results in UV absorption edge shift. According to literature data [30] this shift may be caused by silver bromide precipitation, that has strong absorption in this area.
Figure 5 illustrates the absorption spectra of UV irradiated for 50 s and heat treated bromide PTR glass and AgBr film at room and liquid nitrogen temperatures [30]. It is well known that cooling of silver bromine results in exciton absorption peaks appearance (295 and 261 nm) [30]. At the same time cooled bromide PTR glasses with high bromine concentration (≥ 0.5 mol.%) show presence of the same absorption peaks, that slightly shifted towards to the higher energies, seemingly due to a small size of silver bromide nanocrystals. Also XRD analysis of PTR glass with 1.5 mol.% of Br was conducted to determine phases precipitated in glass bulk after the UV irradiation for 50 s and subsequent thermal treatment (inset Fig. 5).
Fig. 5 Absorption spectra of UV-irradiated (for 50 s) and heat-treated bromide PTR glass containing 0.7 mol.% of Br under liquid nitrogen temperature. 1,2 – Absorption spectra of silver bromide film (250 μm) at room and liquid nitrogen temperatures respectively [27]; 3,4 - Absorption spectra of UV-irradiated (for 50 s) and heat-treated PTR glass at room and liquid nitrogen temperatures respectively. An inset shows the X-ray diffraction pattern of UV-irradiated for 50s and heat treated bromide PTR glass with 1.5 mol.% Br. Reproduced with permission [27]. Copyright 1957, American Physical Society.
Based on XRD analysis and low temperature we can conclude that the thermal treatment of UV-irradiated bromide PTR glasses, seemingly, results in the precipitation of silver bromide nanocristalls which have a strong exсiton absorption [30] in UV and high refractive index [31]. Apparently, based on the absorption spectra of bromide PTR glasses we may conclude that the precipitation of silver bromide nanocrystalls occur around silver nanoparticle. Notably, that the silver bromide can form, according to the AgBr - NaBr phase diagram [32], a continuous series of solid solutions at room temperature if silver or sodium bromide concentrations are low, which can explain the gradual long-wavelength shift of surface plasmon resonance band for the silver nanoparticle. At the same time such gradual shift may be obtained due to thickening of silver bromide shell [26].
Furthermore, using Scherrer formula [33] and XRD analysis data, we can numerically evaluate the size of AgBr nanocrystals, which equal to 11 nm for the PTR glass doped with 1.5 mol.% Br. As well it is possible to calculate the size of silver nanoparticles, applying Mie theory [27,28] to the absorption spectra, the size of NPs being found to be less than 3 nm for all UV-irradiated (50 s) and heat treated bromide PTR glasses (Fig. 4).
In accordance with Rayleigh and Mie scattering theories and the above size calculations for silver nanoparticles and silver bromide crystals, it is reasonable to draw a conclusion that there should be now light scattering on them in the 800-2500 nm range, Fig. 7.
In accord with the above, we can conclude that the UV irradiation of all studied bromide PTR glass results in the Ce3+ ions photoionization and the SMC formation, the latter playing the role of crystallization centers Fig. 6(a). Heating of all studied bromide PTR glass at temperatures above 250°C and less than Tg results in discharging electrons by Sb and capturing them by Ag ions with further formation of an extra amount of neutral silver atoms and molecular clusters Fig. 6(b) [34,35]. Further heat treatment of PTR glass containing 0.25 – 0.7 mol.% Br at temperatures above Tg leads, as we suppose, to the precipitation of silver nanoparticles with the silver bromide shell which has various thickness [26] and/or composition [32] (mixed silver and sodium bromides), and shifts plasmon resonance absorption band towards to the greater wavelengths Fig. 6(c). At the same time, as we consider, such treatment of PTR glass containing from 1.0 to 1.5 mol.% Br results in the precipitation of small silver nanonoparticles, without palpable plasmon resonance absorption peak, which are covered by a shell consisting of silver bromide Fig. 6(c), that are manifest themselves by the shifting of the short-wave absorption edge towards to the greater wavelengths.
Fig. 6 Scheme for the photo-thermo-induced crystallization mechanism inherent in bromide PTR glass for various Br concentrations (0 – 1.5 mol.%). a – Photoactivation of PTR glass (Ce3+ ion photoionization), formation of neutral silver molecular clusters, and capturing electrons by Sb5+ ions. b – Discharging electrons by Sb and capturing them by Ag ions with the formation of neutral silver atoms and clusters. c –Growth of silver nanoparticles with the shell composed of silver bromide in glass containing 0.25 – 0.7 mol.% Br and growth of the small silver nanoparticles with broad plasmon resonance peak, covered by the shell made of silver bromide nonocrystals in glass containing 1 – 1.5 mol.% Br.
Figure 7 illustrates the absorption spectra of PTR glass containing 0.7 mol.% Br observable at all stages of photo-thermo-induced crystallization. As seen from Fig. 7, the crystallization of silver nanoparticles and silver bromide crystalline phase occurs only in the UV-irradiated and then heat-treated area, whereas the thermal treatment of unirradiated area imposes no measurable effect on the absorption spectra of bromide PTR glass with low (0 – 0.7 mol.%) bromine concentration. On the other hand, the increase in Br concentration (1 and 1.5 mol.%) leads to spontaneous precipitation of silver bromide in the unirradiated area during thermal treatment at the temperatures greater than Tg.
Fig. 7 Absorption spectra of PTR glass containing 0.7 mol.% Br. (1) is the spectrum for initial untreated glass, (2) is that for glass after the UV irradiation for 50 s. alone, (3) is the spectrum for glass after the heat treatment alone, and (4) is the one for glass after the UV irradiation for 50 s and subsequent heat treatment. An inset shows the photos and the absorption spectra (700-2500nm) of treated bromide PTR glass samples containing 0.7 mol.% Br. (1) is initial untreated glass, (2) is the glass after the UV irradiation for 50 s alone, (3) is the glass after the heat treatment alone, and (4) is the glass after the UV irradiation for 50 s and subsequent heat treatment.
According to data in [26], the plasmon resonance maximum of silver nanoparticles displays the treatment-induced long-wavelength shift. Also, both silver bromide [31] and sodium bromide [36] have the greater refractive index than PTR glass. So, we conducted some direct measurements of the refractive index in the UV-irradiated and unirradiated areas of heat-treated glass. The measurements showed that the UV irradiation and subsequent heat treatment of bromide PTR glasses result in an increase in the refractive index of the UV-irradiated areas compared to that of unirradiated ones, i.e., the sign of refractive index increment ∆n is positive.
Figure 8 shows the evolution of the refractive index of PTR glass with an increase in the bromine concentration for initial, heat-treated, and UV-irradiated and then heat-treated glasses (curves 1 to 3). As seen, the incorporation of Br results in a consecutive increase in the refractive index of glass irrespective of treatment applied. In particular, Curves 1 and 2 coincide with each other till the bromine concentration is reaches 0.7 mol.%., i.e., the heat treatment of unirradiated bromide PTR glasses with bromine concentration 0.7% find less does not change their refractive index. On the contrary, the UV irradiation and subsequent heat treatment of bromide PTR glass result in a significant increase in their refractive index. For the maximum bromine concentration, a difference Δn between the refractive index values of the UV-irradiated and unirradiated glasses after the heat treatment reaches magnitudes up to + 800 ppm.
Fig. 8 Effect of bromine concentration on the refractive index (nd) of PTR glass. 1 – untreated glass samples, 2 – glass samples after the heat treatment, 3 – glass samples after the UV irradiation and subsequent heat treatment.
In purpose to show capabilities of designed PTR glass experimental samples of a reflecting Bragg grating and a planar waveguide have been recorded by photo-thermo induced crystallization process on glass with 0.7 mol.% of Br. Grating have been recorded using He-Cd laser with a period 1169.3 nm, measured using He-Ne laser (632.8 nm) with Bragg angel 15.7 °. The Fig. 9 presents the angular selectivity of the written Bragg grating. As seen minimum of the zero and maximum of the first diffraction orders are shifted relative to each other. Also the left shoulder of the zero diffraction order is lower than the right one. So it is clear that the written grating is amplitude phase one. It should be noted that diffraction efficiency of the written grating is about 60% and refractive index modulation is equal to 4,2*10−4, calculated according to method described in [37,38], inset Fig. 9.
Fig. 9 Angular selectivity of the written Bragg grating, on the inset shown the comparison of calculated and experimentally measured intensity of passed through the Bragg grating radiation. Photo of the reflecting Bragg grating in visible light written on bromide PTR glass with 0.7 mol.% of Br are shown below the inset.
As well a planar waveguide has been formed in PTR glass via consistent UV irradiation through a mask and heat-treatment. Schematically waveguide is shown on Fig. 10. For the measurements, the method of the selective resonance excitation of waveguide modes implemented with the prism couplers of laser beams (λ = 632.8 nm) for the waveguide has been used [39], Fig. 10. The written waveguide has one mode, with the mode structure shown on Fig. 10. The refractive index increment in the waveguide has been calculated applying inverse Wentzel-Kramers-Brillouin method using the measured effective refractive indices [40], and the maximum refractive index increment is shown to be about 5*10−4, that is enough for waveguide structure recording.
Fig. 10 The scheme of the planar waveguide recording and measuring in bromide PTR glass with 0.7 mol. % of Br and reduced SbO2 concentration. 1 – Schematic illustration of waveguide writing process, and photo of UV irradiated sample luminescence with latent image under UV excitation (λex = 365 nm) ; 2 – Manifestation of latent image; 3 – Scheme of the written waveguide measurement by method of the selective resonance excitation of waveguide modes implemented with the prism couplers of laser beams (λ = 632.8 nm) and the photo of the written waveguide mode structure.
Thus, based on the results of the studying spectral and optical properties of bromide PTR glass and also on the XRD analysis data, we may conclude that increase in the glass refractive index is apparently caused by precipitation, in the UV-irradiated area, of the crystalline phase consisting of silver bromide, seemingly, around silver nanoparticle. This phase has the greater refractive index than that of unirradiated glass, so the thickness of this crystalline shell can be one of possible reasons for the gradual long-wavelength shift of the plasmon resonance maximum related to the silver nanoparticles.
One can conclude that the positive refractive index increment of bromide PTR glass that forms in the course of photo-thermo-induced crystallization is the fundamental specific feature of the glass. This feature allows one to use bromide PTR glass for not only hologram recording but also creating waveguide structures via the photo-thermo-induced crystallization process (UV irradiation + heat treatment). Despite the intense surface plasmon resonance absorption band of silver nanoparticles centered at 488 nm, bromide PTR glass is transparent enough in the 800-2500 nm region (the optical losses being no more than 0.35 cm−1), this fact making this glass a promising material for creating certain kinds of the near-IR optical devices.
Conclusions
Bromide PTR glass have been developed and synthesized for the first time. The incorporation of bromine into the PTR glass compositions does not affect strongly the glass absorption spectra and, in particular, generates additional absorption in the region of Ce3+-related band responsible for the PTR glass photosensitivity, apparently due to silver bromide spontaneous precipitation. The presence of bromine in glass results also in an increase in the amount of SMC formed during the UV irradiation as compared to the case of bromine-free PTR glass.
For PTR glasses with bromine concentration 0.7 mol. % and lower, the subsequent UV irradiation and heat treatment, apparently, result in the formation of silver nanoparticles with a silver bromide shell, which shifts plasmon resonance maximum towards to the greater wavelengths by 35 – 68 nm. Also, incorporation of bromine in the concentration within the 0.25 – 0.5 mol. % range leads to the intensification of plasmon resonance band of silver nanoparticles.
For PTR glasses with the higher bromine concentrations (1.0 – 1.5 mol. %), the UV irradiation and subsequent heat treatment result, as we presume, in the precipitation of small silver nanonoparticles, with out palpable plasmon resonance absorption peak, which covered by a shell consisting of silver bromide. Growth of AgBr crystals results in the significant increase in the refractive index of the UV-irradiated area compared to that of unirradiated one, i.e., the sign of the refractive index increment is positive and its magnitude reaches + 800 ppm for the glass with 0.7 mol.% of bromine.
Samples of the Bragg grating and the waveguide structure have been recorded on PTR glass with 0.7 mol.% of Br.
These results allow for considering developed bromide PTR glass as promising photosensitive materials for recording the volume Bragg gratings and also creating waveguide structures via the photo-thermo-induced crystallization process that combines the UV irradiation and subsequent heat treatment.
Funding
Ministry of Education and Science of Russian Federation (#16.1651.2017/ПЧ).
Acknowledgments
The authors are grateful to R. Nuryev for conducting the XRD measurement, to A. Babkina for conducting absorption spectra measurement under liquid nitrogen temperature, to E. Sgibnev and V. Krykova for the waveguide and the Bragg grating recoding respectively, and to Prof. A. Efimov for fruitful discussion and article reviewing.
References and links
1. A. L. Glebov, O. Mokhun, A. Rapaport, S. Vergnole, V. Smirnov, and L. B. Glebov, “Volume Bragg gratings as ultra-narrow and multiband optical filters,” Proc. SPIE 8428, 84280C (2012). [CrossRef]
2. S. A. Ivanov, A. E. Angervaks, and A. S. Shcheulin, “Application of photo-thermo-refractive glass as a holographic medium for holographic collimator gun sights,” Proc. SPIE 9131, 91311B (2014).
3. L. B. Glebov, V. I. Smirnov, C. M. Stickley, and I. V. Ciapurin, “New approach to robust optics for HEL systems,” Proc. SPIE 4724, 101–109 (2002). [CrossRef]
4. S. A. Ivanov and V. A. Aseev, “Resonator free Er-Yb laser based on photo-thermo-refractive (PTR) glass,” Proc. SPIE 8959, 89591E (2014).
5. L. B. Glebov, “Photosensitive holographic glass – new approach to creation of high power lasers,” Phys. Chem. Glas. J. Glas. Sci. Technol. Part B 48(3), 123–128 (2007).
6. A. I. Ignatiev, D. A. Klyukin, V. S. Leontieva, N. V. Nikonorov, T. A. Shakhverdov, and A. I. Sidorov, “Formation of luminescent centers in photo-thermo-refractive silicate glasses under the action of UV laser nanosecond pulses,” Opt. Mater. Express 5(7), 1635 (2015). [CrossRef]
7. Y. Sgibnev, N. Nikonorov, A. Ignatiev, V. Vasilyev, and M. Sorokina, “Photostructurable photo-thermo-refractive glass,” Opt. Express 24(5), 4563 (2016). [CrossRef]
8. Y. M. Sgibnev, N. V. Nikonorov, V. N. Vasilev, and A. I. Ignatiev, “Optical gradient waveguides in photo-thermo-refractive glass formed by ion exchange method,” 33(17), 3730–3735 (2015).
9. N. V. Nikonorov, E. I. Panysheva, I. V. Tunimanova, and A. V. Chukharev, “Influence of glass composition on the refractive index change upon photothermoinduced crystallization,” Glass Phys. Chem. 27(3), 241–249 (2001). [CrossRef]
10. L. Glebova, J. Lumeau, M. Klimov, E. D. Zanotto, and L. B. Glebov, “Role of bromine on the thermal and optical properties of photo-thermo-refractive glass,” J. Non-Cryst. Solids 354(2-9), 456–461 (2008). [CrossRef]
11. S. D. Stookey, G. H. Beall, and J. E. Pierson, “Full-color photosensitive glass,” J. Appl. Phys. 49(10), 5114–5123 (1978). [CrossRef]
12. V. D. Dubrovin, A. I. Ignatiev, N. V. Nikonorov, A. I. Sidorov, T. A. Shakhverdov, and D. S. Agafonova, “Luminescence of silver molecular clusters in photo-thermo-refractive glasses,” Opt. Mater. (Amst) 36(4), 753–759 (2014). [CrossRef]
13. I. Dyamant, A. S. Abyzov, V. M. Fokin, E. D. Zanotto, J. Lumeau, L. N. Glebova, and L. B. Glebov, “Crystal nucleation and growth kinetics of NaF in photo-thermo-refractive glass,” J. Non-Cryst. Solids 378, 115–120 (2013). [CrossRef]
14. L. B. Glebov, N. V. Nikonorov, E. I. Panysheva, G. T. Petrovskii, V. V. Savvin, I. V. Tunimanova, and V. Tsekhomskii, “New ways to use photosensitive glasses for recording volume phase holograms,” Opt. Spectrosc. 73(2), 237–241 (1992).
15. J. Lumeau, L. Glebova, and L. B. Glebov, “Influence of UV-exposure on the crystallization and optical properties of photo-thermo-refractive glass,” J. Non-Cryst. Solids 354(2-9), 425–430 (2008). [CrossRef]
16. J. Lumeau and E. D. Zanotto, “A review of the photo-thermal mechanism and crystallization of photo-thermo-refractive (PTR) glass,” Int. Mater. Rev. 6608(December), 1–19 (2016). [CrossRef]
17. V. D. Dubrovin, A. I. Ignatiev, and N. V. Nikonorov, “Chloride photo-thermo-refractive glasses,” Opt. Mater. Express 6(5), 1701 (2016). [CrossRef]
18. N. V. Nikonorov, A. I. Sidorov, and V. A. Tsekhomskii, “Silver Nanoparticles in Oxide Glasses: Technologies and Properties,” in Silver Nanoparticles, D. P. Perez, ed. (In-Tech, 2010), p.177.
19. S. E. Paje, M. A. García, M. A. Villegas, and J. Llopis, “Optical properties of silver ion-exchanged antimony doped glass,” J. Non-Cryst. Solids 278(1–3), 128–136 (2000). [CrossRef]
20. A. M. Efimov, A. I. Ignatiev, N. V. Nikonorov, and E. S. Postnikov, “Quantitative UV-VIS spectroscopic studies of photo-thermo-refractive glasses. II. Manifestations of Ce3+ and Ce(IV) valence states in the UV absorption spectrum of cerium-doped photo-thermo-refractive matrix glasses,” J. Non-Cryst. Solids 361(1), 26–37 (2013). [CrossRef]
21. A. M. Efimov, A. I. Ignatiev, N. V. Nikonorov, and E. S. Postnikov, “Quantitative UV-VIS spectroscopic studies of photo-thermo-refractive glasses. I. Intrinsic, bromine-related, and impurity-related UV absorption in photo-thermo-refractive glass matrices,” J. Non-Cryst. Solids 357(19–20), 3500–3512 (2011). [CrossRef]
22. O. V. Butov, K. M. Golant, A. L. Tomashuk, M. J. N. van Stralen, and A. H. E. Breuls, “Refractive index dispersion of doped silica for fiber optics,” Opt. Commun. 213(4-6), 301–308 (2002). [CrossRef]
23. I. Dyamant, A. S. Abyzov, V. M. Fokin, E. D. Zanotto, J. Lumeau, L. N. Glebova, and L. B. Glebov, “Crystal nucleation and growth kinetics of NaF in photo-thermo-refractive glass,” J. Non-Cryst. Solids 378, 115–120 (2013). [CrossRef]
24. S. A. Nikonorov, V. Aseev, A. Ignatiev, E. Kolobkova, “Novel glasses and nanoglassceramics for photonic and plasmonic applications,” in Thirteenth International Conference on the Physics of Non-Crystalline Solids, 89.
25. S. Zhao, Z.-H. Li, W.-N. Wang, and K.-N. Fan, “Density functional study of the interaction of chlorine atom with small neutral and charged silver clusters,” J. Chem. Phys. 122(14), 144701 (2005). [CrossRef] [PubMed]
26. N. V. Nikonorov, A. I. Sidorov, V. A. Tsekhomskiĭ, and K. E. Lazareva, “Effect of a dielectric shell of a silver nanoparticle on the spectral position of the plasmon resonance of the nanoparticle in photochromic glass,” Opt. Spectrosc. 107(5), 705–707 (2009). [CrossRef]
27. H. Hövel, S. Fritz, A. Hilger, U. Kreibig, and M. Vollmer, “Width of cluster plasmon resonances: Bulk dielectric functions and chemical interface damping,” Phys. Rev. B Condens. Matter 48(24), 18178–18188 (1993). [CrossRef] [PubMed]
28. G. W. Arnold, “Near-surface nucleation and crystallization of an ion-implanted lithia-alumina-silica glass,” J. Appl. Phys. 46(10), 4466–4473 (1975). [CrossRef]
29. A. Simo, J. Polte, N. Pfänder, U. Vainio, F. Emmerling, and K. Rademann, “Formation Mechanism of Silver Nanoparticles Stabilized in Glassy Matrices Formation Mechanism of Silver Nanoparticles Stabilized in Glassy Matrices,” 134(45), 18824–18833 (2012).
30. S. Tutihasi, “Optical Absorption by Silver Halides,” Phys. Rev. 105(3), 882–884 (1957). [CrossRef]
31. V. H. Sehr, “Über die Brechungsindizes einiger Schwermetallhalogenide im Sichtbaren und die Berechnung von Interpolationsformeln für den Dispersionsverlauf,” Z. Phys. 67(1), 24–36 (1931).
32. C. Sinistri, R. Riccardu, C. Margheritis, and P. Tittarelli, “Thermodynamic Properties of Solid Systems AgCl + NaCl and AgBr + NaBr from Miscibility Gap Measurements,” Z. Naturforsch. A 21(1), 149–154 (1972).
33. A. L. Patterson, “The scherrer formula for X-ray particle size determination,” Phys. Rev. 56(10), 978–982 (1939). [CrossRef]
34. S. A. Ivanov, A. I. Ignatiev, and N. V. Nikonorov, “Advances in photo-thermo-refractive glass composition modifications,” Proc. SPIE 9508, 95080E (2015).
35. V. D. Dubrovin, A. I. Ignat’ev, N. V. Nikonorov, and A. I. Sidorov, “Influence of halogenides on luminescence from silver molecular clusters in photothermorefractive glasses,” Tech. Phys. 59(5), 733–735 (2014). [CrossRef]
36. H. H. Li, “Refractive index of alkaline earth halides and its wavelength and temperature derivatives,” J. Phys. Chem. Ref. Data 5(2), 329–528 (1976). [CrossRef]
37. L. Carretero, R. F. Madrigal, A. Fimia, S. Blaya, and A. Beléndez, “Study of angular responses of mixed amplitude--phase holographic gratings: shifted Borrmann effect,” Opt. Lett. 26(11), 786–788 (2001). [CrossRef] [PubMed]
38. S. A. Ivanov, A. I. Ignatiev, N. V. Nikonorov, and V. A. Aseev, “Holographic characteristics of a modified photothermorefractive glass,” J. Opt. Technol. 81(6), 356–360 (2014). [CrossRef]
39. R. Ulrich and R. Torge, “Measurement of thin film parameters with a prism coupler,” Appl. Opt. 12(12), 2901–2908 (1973). [CrossRef] [PubMed]
40. J. M. White and P. F. Heidrich, “Optical waveguide refractive index profiles determined from measurement of mode indices: a simple analysis,” Appl. Opt. 15(1), 151–155 (1976). [CrossRef] [PubMed]
