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ADDITIONS AND CORRECTIONS 2006, Volume 111B I. V. Kityk,* Qingsheng Liu, Zhaoyong Sun, Jiye Fang*: Low-Temperature Anomalies of Two-Proton Absorption in In2O3 Nanocrystals Incorporated into PMMA Matrixes Pages 8219-8222: Several additional clarifications and extensions concerning the obtained nonlinear optical data and several measurement details in the article Kityk, I. V.; Liu, Q.; Sun, Z.; Fang, J. J. Phys. Chem. B 2006, 110, 8219 will be given. The obtained value of the TPA (about 90 cm/GW) is of the same order as for other semiconducting nanocomposites. For example, for the same PMMA matrices, TiO2 embedded nanocrystals (NC) give 2260 cm/GW (at least two order larger).1 For the ZnS NP, the enhancement achieves about 230 cm/GW.2 For comparison in the bulk ZnS crystals, this coefficient is equal to only 0.02 cm/GW, which confirms its nanosized origin. Even for such nonpromising nonlinear crystals as GaAs without the polymer covering sheets, the value of the TPA is equal up to 40 cm/GW, which is larger than for many organic materials.3 The optimal content of the chromophore (about 4.3%), which usually do not exceed 5.4% for typical semiconducting nanocrystallite-polymer composites (in weight), corresponds to maximal content at which the NC aggregation do not occur yet. Usually for larger NC contents, one can observe drastic enhancement of the scattered light. This aggregation diminishes the NLO output and this chromophore NC content is very close for many inorganic NC incorporated into the polymer matrices (see for example SiC/PMMA composites4). In the case of the IR spectral wavelengths, additional favoring factor of the nonlinear optical susceptibility enhancement (up to 5 orders) for such nanosized structure is caused by polaronic effects (see for example ref 5). Physical mechanisms determining the observed effects were described elsewhere (see for instance ref 6 and reference there). Recently also it was established that the principal role for such kinds of the nanocomposites play the sheets with thickness from 0.5 up to 5 nm on the borders separating the nanocrystallites and the surrounding polymers. This fact was unambiguously established following the ab initio molecular dynamics and quantum chemical simulations in refs 7 and 8. So effectively we deal with a nanoporous composite material, principally different from amorphous. The influence of the nanosurfaces on the NLO susceptibilities was demonstrated many times experimentally and theoretically (see for example refs 9 and 10). For example for semiconducting CdTe nanocomposites, an enhancement of at least two order of the third-order susceptibilities was observed compared to the bulk one.11 This origin of the nonlinear optical susceptibility is principally different with respect to the organic materials where local hyperpolarizabilities (both of the second as well as of the third order ones) possess a principal theoretical limit.12 Moreover, in several types of metallic nanoparticles, enhancement of the third-order susceptibilities may achieve even 5-6 orders,13 and the role of the nanoconfined effects on the interfaces is crucial. The technology of preparaing optically homogeneous nanocomposites always includes several field alignments causing the
macroscopically polarizability of the composites similarly to partially oriented materials. This is not the principal for the TPA described by fourth rank tensors; however, this is crucial for investigations of the second-order optical effects14 described by third rank polar tensors. In this case, additional optically induced polarized anisotropy is used. The observed temperature TPA singularities also are determined by temperature anomalies of nanointerfaces in In2O3 NC/ polymer borders.15 Then the temperature range of the corresponding anomalies (low- or high temperature ones) is determined by relative thermal expansion of the NC with respect to the surrounding matrices. This has an influence on nonlinear optical susceptibility coefficients which are very sensitive to such kinds of temperature phase transformations (see for example ref 16). An additional specific feature of the investigated nanocomposites is an occurrence of substantial reversible photobleaching (darkening) effects originating from the nanoconfined states formed by photocarriers trapped by interface states (which are absent in the pure organic crystalline materials). Generally the origin of the third-order optical processes is principally different compared to the organic materials (particularly crystalline) and is more similar to the narrow-gap semiconductors or photochromic materials (see for example ref 17). For semiconducting nanocrystallites incorporated into the polymer matrices, the thermodegradation power threshold is substantially shifted toward larger power densities compared with typical organic materials due to variations of the thermoconductivity, carrier thermodiffusion in the nanosheet voids appeared on the interfaces of the porous-like structures. This fact is used for their application as thermostable materials. Principal physical origin is described elsewhere (see for example refs 18 and 19). Another topics requiring additional explanation is the Gd3+YAG laser source. Explanation of this laser systems was just given in several of our previous technical reports and works, (see for example the recent work in ref 20), where it was explained that Gd+3YAG lasers present the traditional Nd:YAG laser pumping crystalline optical parametric generator (OPG), containing the Gd3+ ions. In principle it is the OPG tuned IR laser system which is widely commercially used up to 2300 nm wavelength. As a consequence we have introduced an abbreviation showing the principal ions (to differ from another), particularly Gd3+ ones present in the Gd3+ borate NLO GdCOB (GdAlOB) crystals to differentiate them from the borates with other cations (Bi 3+, Li+, Ba 2+, etc.). Such a system presents typical OPG assisted laser systems, which are usually described in such a form for the commercial quantum electronic license devices and corresponding patents. There are a lot of works where IR laser tuning of light up to the 2500 nm was realized using the borate crystals, doped by different rare earth ions, including Gd3+ (see for example the recent ref 21). The Gd3+-containing borates present efficient materials for these goals,22 and principles of the corresponding laser generation are based on the selffrequency conversion, Raman shifts, and participation of the rare earth ions emissions.23,24 It is obvious that Gd3+ centers are not the emitting centers because they have emission in the
2292 J. Phys. Chem. B, Vol. 112, No. 7, 2008 UV spectral range. Varying the doped rare earth ions (usually Nd+3, Pr+3, Tu3+, or Ho+3) in co-doping regime, generation from 1.76 µm, 2.03 µm, 1.69 µm, etc was achieved. Generally for today by varying of the rare earth doping and OPG crystalline geometry, at least 50 IR laser discrete wavelength generation is realized within the 1.67-2.36 µm spectral range. One of the advantages compared to the use of the other borate spectrally tuned OPG (so-called Bi+3-YAG laser) operating within the spectral range 700-2450 nm25,26 is the possibility to achieve more narrow spectral bands. This one allows us to change the optical path shift (time delay) with precision to less than a picosecond on the electrooptical triggering. The active or passive “opening” of the time clock is dependent on the temporary front of the optically operated trigger pulses, which may be varied up to the subpicosecond range even for operating the nanosecond pulses. Varying the dc-electrooptical electric field, the effective birefringence, and the optical path, one can achieve desirable pump-probe opening clocks. This was realized by use of the such types of optically operated nonlinear materials in many other previous works,27,28 and there is not a principal limit for realization of such kinds of systems. However, the obtained pump-probe time delay is not the same as for the real coherent time pulse coincidence which is principally impossible for the different pulse durations. So it corresponds to the delay shift of the package at all playing principle role for the investigation of the electron-lattice realizations. A similar situation exists for the Er3+-YAG laser in ref 29, which presents “erbium-yttrium aluminum garnett doped by thullium+ emitting ions generating at 1880 nm”. Analogously the laser source in ref 30 presents a 25 ps Nd:YAG laser. These technical details should be taken into consideration to avoid several misunderstandings with the experimental details. References and Notes (1) Yuwono, A. H.; Liu, B.; Xue, J.; Wang, J.; Elim, H. J.; Ji, W.; Li, Y.; White, T. J. J. Mater. Chem. 2004, 14, 2978. (2) Wang, X.; Du, Y.; Ding, S.; Fan, L.; Shi, X.; Wang, Q. Q.; Xiang, G. Phys. E 2005, 30, 96. (3) Li, Q.; Liu, C.; Liu, Z.; Cong, Q. Opt. Express 2005, V.13, 1833. (4) Boucle, J.; et al. Phys. ReV. 2006, B74, 205417.
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Additions and Corrections (5) Chao-Jin Zhang, C.-J.; Guo, K.-X. Phys. B: Condensed Matter 2007, 387, 276. (6) Karabulut, I.; Safat, H. Phys. B: Condensed Matter 2005, 368, 82. (7) Makowska-Janusik, M.; Reis, H.; Papadopoulos, M.; Economou, M. G.; Zacharopolulos, N. J. Phys. Chem. B 2004, 108, 588. (8) Pud, A. A.; Noskov, Yu. V.; Kassiba, A.; Fatyeva, K. Yu.; Ogurtsov, N. A.; Makowska-Janusik, M.; Bednarski, N.; Tabellbot, M.; Shapoval, G. S. J. Phys. Chem. B 2007, 111, 2174. (9) Liu, B.; Chew, C.H.; Gan, L.M.; Xu, G. Q.; Li, H.; Lam,Y. L.; Kam, C. H.; Que, W. X. J. Mater. Res. 2001, 16, 1644. (10) Lu, S. W.; Soohl;ig, U.; Menning, M.; Schmidt, H. S. Nanotechnology 2002, 13, 669. (11) Tan, G. L.; Yang, Q.; Hommerich, U.; Seo, J. T.; Temple, D. Opt. Mater. 2004, 27, 579. (12) Kuzyk, M. G. J. Chem. Phys. 2003, 119, 8327. (13) Giorgetti, E.; Margheri, G.; Sottini, S.; Toci, G.; Muniz-Mianda, M.; Moroni, L.; Delpiani, G. Phys. Chem. Chem. Phys. 2002, 4, 2762. (14) Sahraoui, B.; Kityk, I. V.; Hudhomme, P.; Gorgues, A. J. Phys. Chem. B 2001, 105 (27), 6295-6299. (15) Singh, V. N.; Methta, B. R. Nanosci. Nanotechnol. 2005, 5, 431. (16) Kasprowicz, D.; Kroupa, J.; Majchrowski, A.; Michalski, E.; Drozdowskui, M.; Zmija, J. Cryst. Res. Technol. 2003, 38, 374. (17) Feneryrou, P.; Soyer, F.; Le Barny, P.; Ishow, E.; Sliwa, M.; Delaire, J. A. Photochem. Photobiol. Sci. 2003, 2, 195-202. (18) Hedrick, J. L.; et al. In Nanoporous Polymers; Springer: Berlin, 1999; Vol. 141, pp 1-43. (19) Liu, P.-T.; Chang, T. H.; Hsu, K. C.; Tseng, T. Y.; Chen, L. M.; Wang, C. J.; See, S. M. Thin Solid Films 2002, 414, 1; Li, L.; Wang, Y. J. Power Sources 2006, 162, 541. (20) Ebothe, J.; Plucinski, K. J.; Nouneh, K.; Roca Cabarrocas, P.; Kityk, I. V. J. Nanomater. 2006, ID63608. (21) Sun, Z.; Ghotbi, M.; Ebrahimzadeh, M. Opt. Express 2007, 15 4138. (22) Brenier, A.; Jaque, D.; Majchrowski, A. Opt. Mater. 2006, 28, 310. (23) Mefleh, A.; Benet, S.; Brunet, S.; Kaddouri, H.; Sahraoui, B.; Kityk, I. V.; Makowska-Janusik, M. Opt. Mater. 1999, 13, 339. (24) Brenier, A.; Kityk, I. V. J. Appl. Phys. 2001, 90, 232. (25) Sun, Z.; Ghotbi, M.; Ebrahimzadeh, M. Opt. Express 2007, 15, 5360. (26) Nikogosyan, D. N. Nonlinear Optical Crystals. A Complete SurVey; Springer: New York, 2005; p 275. (27) Kityk, I. V. J. Phys. Chem. B 2003, 107, 10083. (28) Kityk, I. V.; Sahraoui, B. J. Phys. Chem. B 2005, 109, 3163. (29) Migalska-Zalas, M.; Sofiani, Z.; Sahraoui, B.; Kityk, I. V.; Tkaczyk, S.; Yuvshenko, V.; Fillaut, J.-L.; Perruchon, J.; Muller, T. J. J. J. Phys. Chem. B 2004, 108, 14942. (30) Makowska-Janusik, M.; Tkaczyk, S.; Kityk, I. V. J. Phys. Chem. B 2006, 110, 6492-6498. 10.1021/jp0771973 Published on Web 01/29/2008
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