OSA's Digital Library

Optics Express

Optics Express

  • Editor: Michael Duncan
  • Vol. 12, Iss. 17 — Aug. 23, 2004
  • pp: 4035–4040
« Show journal navigation

Controllable precipitation and dissolution of silver nanoparticles in ultrafast laser pulses irradiated Ag+-doped phosphate glass

Quan-Zhong Zhao, Jian-Rong Qiu, Xiong-Wei Jiang, Chong-Jun Zhao, and Cong-Shan Zhu  »View Author Affiliations


Optics Express, Vol. 12, Issue 17, pp. 4035-4040 (2004)
http://dx.doi.org/10.1364/OPEX.12.004035


View Full Text Article

Acrobat PDF (447 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We report a controllable process of precipitation and dissolution of silver nanoparticles in ultrashort laser pulses irradiated Ag+-doped phosphate glass. Absorption spectra, transmission electron microscopy and refractive index measurement revealed that metallic silver nanoparticles were precipitated in the glass sample after irradiation by an 800-nm femtosecond laser and subsequent annealing at 300°C, and dissolved after further annealing at 450°C. We discuss a mechanism that combines the formation and decoloration of color centers, precipitation and dissolution of silver nanoparticles.

© 2004 Optical Society of America

1. Introduction

Femtosecond ultrashort pulse lasers have become powerful tools for the fabrication of functional optical devices as they can induce various controllable microstructures by microscopic modifications in transparent materials. Different optical functions have been demonstrated, such as fabrication of optical waweguide, coupler and photonic crystal, three-dimensional optical storage and rewritable optical memory [1

1. K. Miura, J. Qiu, H. Inouye, T. Mitsuyu, and K. Hirao, “Photowritten optical waveguides in various glasses with ultrashort pulse laser,” Appl. Phys. Lett. 71, 3329–31 (1997). [CrossRef]

6

6. K. Miura, J. Qiu, S. Fujiwara, S. Sakaguchi, and K. Hirao, “Three-dimensional optical memory with rewriteable and ultrahigh density using the valence-state change of samarium ions,” Appl. Phys. Lett. 80, 2263–65 (2002). [CrossRef]

]. Recently, ultrashort laser interactions with metal ion-doped glasses, especially noble metal ions such as gold and silver ions doped glass, have been extensively studied for the reasons of developing their applications in functional optical devices [7

7. M. Kaempfe, T. Rainer, K.-J. Berg, G. Seifert, and H. Graener, “Ultrashort laser pulse induced deformation of silver nanoparticles in glass,” Appl. Phys. Lett. 74, 1200–02 (1999). [CrossRef]

11

11. J. Qiu, X. Jiang, C. Zhu, M. Shirai, J. Si, N. Jiang, and K. Hirao, “Manipulation of gold nanoparticles inside transparent materials,” Angew. Chem. Int. Ed. 43, 2230–34 (2004). [CrossRef]

]. M. Kaempfe et al. [7

7. M. Kaempfe, T. Rainer, K.-J. Berg, G. Seifert, and H. Graener, “Ultrashort laser pulse induced deformation of silver nanoparticles in glass,” Appl. Phys. Lett. 74, 1200–02 (1999). [CrossRef]

] irradiated intense femtosecond laser pulses on a glass sample containing silver nanoparticles, resulting in permanent colour changes when the laser wavelength was in the region of the particles’ surface plasmon resonance. Y. Watanabe et al. [8

8. Y. Watanabe, G. Namikawa, T. Onuki, K. Nishio, and T. Tsuchiya, “Photosensitivity in phosphate glass doped with Ag+ upon exposure to near-ultraviolet femtosecond laser pulses,” Appl. Phys. Lett. 78, 2125–27 (2001). [CrossRef]

] demonstrated a photosensitivity in soda-alumino-phosphate glass doped with Ag+ upon exposure to near-ultraviolet femtosecond laser pulses and found the formation of color centers such as Ag0 and Ag2+ in the glass. Y. Cheng et al. [9

9. Y. Cheng, K. Sugioka, M. Masuda, K. Shihoyama, K. Toyoda, and K. Midorikawa, “Optical gratings embedded in photosensitive glass by photochemical reaction using a femtosecond laser,” Opt. Express 11, 1809–16 (2003), http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-15-1809 [CrossRef] [PubMed]

] investigated the refractive index change in Ag+ doped Foturan glass by femtosecond laser irradiation followed by postbaking. Qiu et al. [10

10. J. Qiu, M. Shirai, T. Nakaya, J. Si, X. Jiang, C. Zhu, and K. Hirao, “Space-selective precipitation of metal nanoparticles inside glasses,” Appl. Phys. Lett. 81, 3040–42 (2002). [CrossRef]

,11

11. J. Qiu, X. Jiang, C. Zhu, M. Shirai, J. Si, N. Jiang, and K. Hirao, “Manipulation of gold nanoparticles inside transparent materials,” Angew. Chem. Int. Ed. 43, 2230–34 (2004). [CrossRef]

] developed an effective method to space selectively precipitate metal nanoparticles in glass with a femtosecond laser irradiation. Metal nanoparticles with the size of several nanometers could be obtained in selected area inside the glass by using this approach.

In this paper, we report the precipitation and dissolution of silver nanoparticles in Ag+-doped phosphate glass by irradiation with a near-IR 800-nm femtosecond laser pulses and further annealing at various temperature. The mechanisms of the observed phenomena are discussed. We show that the process can be controlled by adjusting the laser parameters and annealing parameters.

2. Experimental

A glass sample with composition of 25Na2O·5Al2O3·70P2O5·0.15Ag2O (in wt%) was prepared from reagent grade Na2CO3, Al(PO3)3, and AgNO3. The mixture of raw materials was melt in an alumina crucible at 1450°C for 1 hour under the ambient atmosphere. Then the melt was quenched into transparent and colorless glass by pouring it onto a stainless steel module at room temperature. Finally the glass was cut and polished into the glass samples with thickness of 3 mm.

A commercial regeneratively amplified 800-nm Ti: Sapphire laser (Spitfire, Spectra- Physics) that emits 120 fs, 1 kHz, mode-locked pulses was used in our experiments. The laser beam with an average power of 3 mW was focused by a 10× objective lens with a numerical aperture of 0.3, and the position of the focal point was 30 µm beneath the sample surface with the help of a computer controlled 3D XYZ stage at the scanning rate of 1000 µm/s.

Grating structures with a period of 20 µm were inscribed into the glass samples by laser direct writing. The size of grating was 3 mm×3 mm to measure the absorption spectrum. After exposure to the femtosecond laser, the sample was subjected to annealing at 150°C, 300°C, 400°C, 450°C, 500°C for 30 min. Optical absorption and photoluminescence spectra of the glass sample were measured using a Jasco V-570 spectrophotometer and Jasco FP-6500 spectrofluorometer, respectively. The precipitation and dissolution of silver nanoparticles were observed by a JEOL JEM-2010 transmission electron microscope (TEM). Also, the refractive index change of laser-irradiated area was evaluated by examining the diffraction efficiencies of grating using a He-Ne laser beam with the wavelength of 633 nm.

3. Results and discussion

Figure 1(a) shows absorption spectra for the Ag+-doped glass sample before (A) and after (B) femtosecond laser irradiation, and subsequent annealing at various temperatures for 30 min. As seen in Fig. 1(a), no apparent absorption (curve A) was observed at the wavelength longer than 350 nm for the unirradiated glass sample. It should be noted that there is no intrinsic absorption at the wavelength of 800 nm for the glass sample. After irradiation, there was an apparent increase in the absorbance as shown in curve B. With increasing the annealing temperature, the absorption for the irradiated glass sample gradually decreased, and the tendency of decrease was weaker after annealed at 500°C, as shown in curves C to G. Figure 1(b) is the difference in absorption spectra of the glass samples in Fig. 1(a) before and after the femtosecond laser irradiation and after subsequent annealing at various temperatures for 30 min. In the difference spectra, there was an apparent absorption band ranging from 250 to 400 nm (curve H), peaking at 320 nm, which was attributed to the formation of color centers associated with Ag+, i. e., trapped electron center Ag0 and trapped hole center Ag2+ in the glass sample [8

8. Y. Watanabe, G. Namikawa, T. Onuki, K. Nishio, and T. Tsuchiya, “Photosensitivity in phosphate glass doped with Ag+ upon exposure to near-ultraviolet femtosecond laser pulses,” Appl. Phys. Lett. 78, 2125–27 (2001). [CrossRef]

,12

12. T. Feldman and A. Treinin, “Inorganic radicals trapped in glasses at room temperature. IV. Silver radicals in metaphosphate glass,” J. Chem. Phys. 47, 2754–58 (1967). [CrossRef]

]. After annealing at 150oC, the absorption band decreased slightly (curve I). While, the absorption band disappeared after annealing at 300°C, indicating that electrons/holes at traps were released by thermal stimulation and recombine with holes/electrons again. In addition, a new absorption band peaking at 450 nm appeared (curve J) which can be assigned to the absorption due to the surface plasmon of the metallic silver nanoparticle [13

13. I. Tanahashi, M. Yoshida, Y. Manabe, and T. Tohda, “Effects of heat treatment on Ag particle growth and optical properties in Ag/SiO2 glass composite thin films,” J. Mater. Res. 10, 362–65(1995). [CrossRef]

]. Base on the Mie theory [14

14. G. Mie, “Beiträge zur optik trüber medien, speziell kolloidaler metallösungen,” Ann. Phys. 25, 377–445 (1908). [CrossRef]

], the calculated average radii of silver nanoparticles are about 5 nm.

Fig. 1. (a) Absorption spectra of Ag+-doped glass sample before (A) and after (B) femtosecond laser irradiation, and subsequent annealing at various temperatures of 150°C (C), 300°C (D), 400°C (E), 450°C (F) and 500°C (G) for 30 min. (b) The difference in absorption spectra of the glass samples in Fig. 1(a) before and after (H=B-A) the femtosecond laser irradiation and after subsequent annealing at various temperatures of 150°C (I=C-A), 300°C (J=D-A), 400°C (K=EA), 450°C (L=F-A) and 500°C (M=G-A) for 30 min. The inset is the amplification of curves J and K.

Preliminary observation with a TEM showed that the precipitation of silver nanoparticles with diameters ranging from 10 to 20 nm in the glass sample as shown in Fig. 2. Composition analysis using energy dispersive spectroscopy (EDS) in TEM confirms that these spherical nanoparticles are metallic silver. After annealing at 400°C, the silver nanopartice surface plasmon absorption peak decreased (curve K). The surface plasmon absorption peak disappeared when the annealing temperature reached 450°C (curve L). Also, the TEM observation confirmed the dissolution of silver nanoparticles.

Fig. 2. TEM micrograph of silver nanoparticles precipitated in Ag2O-doped phosphate glass after femtosecond laser irradiation and annealing at 300°C for 30 min.

It is well known that both Ag0 and Ag2+ centers possess bright orange fluorescence against excitation with UV light [8

8. Y. Watanabe, G. Namikawa, T. Onuki, K. Nishio, and T. Tsuchiya, “Photosensitivity in phosphate glass doped with Ag+ upon exposure to near-ultraviolet femtosecond laser pulses,” Appl. Phys. Lett. 78, 2125–27 (2001). [CrossRef]

]. Figure 3 shows the excitation and emission spectra for the glass sample after femtosecond laser irradiation and further annealing at different temperatures. Curve A represents the excitation spectrum obtained with fluorenscence at 565 nm, while curve B represents the fluorescence spectrum obtained with excitation at 320 nm. Curves C and D represent the excitation and emission spectra after annealing at 150°C. After annealing at 300°C, no emission was detected for the glass sample.

Fig. 3. Excitation and emission spectra of Ag-associated color centers (λexcitation=320nm, λemission=565nm) after femtosecond laser irradiation (A, B) and subsequent annealing at 150°C (C, D). After annealing at 300°C, no emission was detected.

We also investigated the effect of precipitation and dissolution of silver nanoparticles at different annealing temperature on refractive index change in laser-irradiated area by measuring the first-order diffraction efficiencies of the grating written inside the glass sample. Based on the coupled wave theory of Kogelnik’s [15

15. H. Kogelnik, “Coupled wave theory for thick hologram gratings,” Bell Syst. Tech. J. 48, 2909–47 (1969).

], we can deduce the refractive index change (Δn) of the laser-irradiated area. The details for the calculation of refractive index change are reported in Reference 16.

Figure 4 shows both the refractive index change and the diffraction efficiency in the laser-irradiated area as functions of annealing temperature. After femtosecond laser irradiation, there was an increase of 6.12×10-4 for the refractive index with diffraction efficiency of 9.51%. After annealing at 150°C, the diffraction efficiency of the grating and the refractive index change in the irradiated area decrease slightly, while after annealing at 300°C, the diffraction efficiency of the grating and the refractive index change in the irradiated area have an increase compared to those at the state after laser irradiation, indicating that the precipitation of silver nanoparticles plays a role for the increase of refractive index. After annealing at 400°C, the diffraction efficiency of the grating and the refractive index change in the irradiated area decrease again. After annealing at 450°C, it appears that both diffraction efficiency and refractive index change nearly decreases to zero. These changes were also observed from the diffractive patterns, i. e., the brighter diffraction pattern of the first order can be seen after the glass sample was annealed at 300°C in comparison with the irradiation state, while the brightness of diffraction pattern of the first order waken and finally disappeared after annealing at 400°C and 450°C.

Fig. 4. The diffraction efficiency and the refractive index change in the laser-irradiated area as functions of annealing temperature.

Fig. 5. Excitation and emission spectra of isolated Ag+excitation=237nm, λemission=390nm) before (A, B) and after (C, D) femtosecond laser irradiation and subsequent annealing at 300°C (E, F).

It is worthy to mention that the refractive index change for the laser-irradiated area in the glass sample is effected by color centers, permanent structural changes and precipitation of silver nanoparticles induced by femtosecond laser. In the present results, the refractive index change is mainly caused by permanent structural changes such as local densification, local structural rearrangement, etc. Decoloration of color centers lead to some little decrease of refractive index, while the precipitation of silver nanoparticles can increase the refractive index. Therefore we can selectively increase the refractive index by precipitation of metallic nanopartices in expected region in this kind of glasses. For the present laser power of 3 mW, the refractive index has a slight increase after the precipitation of silver nanoparticles, In order to get higher refractive index change, increasing the laser power density and the doped concentration of silver ions should be a feasible method.

4. Conclusions

In summary, we have reported the formation and decoloration of Ag-associated color centers and precipitation and dissolution of silver nanoparticles in Ag+-doped phosphate glass. The process can be controlled by adjusting the laser irradiation parameters and annealing parameters. The above results should be applicable in the fields such as ultrafast all-optical switching devices and high-density optical data storage systems, etc.

Acknowledgments

The authors would like to acknowledge the financial support provided by the National Natural Science Foundation of China (Grant number: 50125208) and Q. Z. Zhao gratefully acknowledges the support of China Postdoctoral Science Foundation, and K. C. Wong Education Foundation, Hong Kong.

References and links

1.

K. Miura, J. Qiu, H. Inouye, T. Mitsuyu, and K. Hirao, “Photowritten optical waveguides in various glasses with ultrashort pulse laser,” Appl. Phys. Lett. 71, 3329–31 (1997). [CrossRef]

2.

A. M. Streltsov and N. F. Borrelli, “Fabrication and analysis of a directional coupler written in glass by nanojoule femtosecond laser pulses,” Opt. Lett. 26, 42–43 (2001). [CrossRef]

3.

K. Minoshima, A. M. Kowalevicz, I. Hartl, E. P. Ippen, and J. G. Fujimoto, “Photonic device fabrication in glass by use of nonlinear materials processing with a femtosecond laser oscillator,” Opt. Lett. 26, 1516–18 (2001). [CrossRef]

4.

H. Sun, Y. Xu, S. Juodkazis, K. Sun, M. Watanabe, S. Matsuo, H. Misawa, and J. Nishii, “Arbitrary-lattice photonic crystals created by multiphoton microfabrication,” Opt. Lett. 26, 325–27 (2001). [CrossRef]

5.

E. N. Glezer, M. Milosavljevic, L. Huang, R. J. Finlay, T.-H. Her, J. P. Callan, and E. Mazur, “Threedimensional optical storage inside transparent materials,” Opt. Lett. 21, 2023–25 (1996). [CrossRef] [PubMed]

6.

K. Miura, J. Qiu, S. Fujiwara, S. Sakaguchi, and K. Hirao, “Three-dimensional optical memory with rewriteable and ultrahigh density using the valence-state change of samarium ions,” Appl. Phys. Lett. 80, 2263–65 (2002). [CrossRef]

7.

M. Kaempfe, T. Rainer, K.-J. Berg, G. Seifert, and H. Graener, “Ultrashort laser pulse induced deformation of silver nanoparticles in glass,” Appl. Phys. Lett. 74, 1200–02 (1999). [CrossRef]

8.

Y. Watanabe, G. Namikawa, T. Onuki, K. Nishio, and T. Tsuchiya, “Photosensitivity in phosphate glass doped with Ag+ upon exposure to near-ultraviolet femtosecond laser pulses,” Appl. Phys. Lett. 78, 2125–27 (2001). [CrossRef]

9.

Y. Cheng, K. Sugioka, M. Masuda, K. Shihoyama, K. Toyoda, and K. Midorikawa, “Optical gratings embedded in photosensitive glass by photochemical reaction using a femtosecond laser,” Opt. Express 11, 1809–16 (2003), http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-15-1809 [CrossRef] [PubMed]

10.

J. Qiu, M. Shirai, T. Nakaya, J. Si, X. Jiang, C. Zhu, and K. Hirao, “Space-selective precipitation of metal nanoparticles inside glasses,” Appl. Phys. Lett. 81, 3040–42 (2002). [CrossRef]

11.

J. Qiu, X. Jiang, C. Zhu, M. Shirai, J. Si, N. Jiang, and K. Hirao, “Manipulation of gold nanoparticles inside transparent materials,” Angew. Chem. Int. Ed. 43, 2230–34 (2004). [CrossRef]

12.

T. Feldman and A. Treinin, “Inorganic radicals trapped in glasses at room temperature. IV. Silver radicals in metaphosphate glass,” J. Chem. Phys. 47, 2754–58 (1967). [CrossRef]

13.

I. Tanahashi, M. Yoshida, Y. Manabe, and T. Tohda, “Effects of heat treatment on Ag particle growth and optical properties in Ag/SiO2 glass composite thin films,” J. Mater. Res. 10, 362–65(1995). [CrossRef]

14.

G. Mie, “Beiträge zur optik trüber medien, speziell kolloidaler metallösungen,” Ann. Phys. 25, 377–445 (1908). [CrossRef]

15.

H. Kogelnik, “Coupled wave theory for thick hologram gratings,” Bell Syst. Tech. J. 48, 2909–47 (1969).

16.

Q. Z. Zhao, J. R. Qiu, X. W. Jiang, C. J. Zhao, and C. S. Zhu, “Fabrication of internal diffraction gratings in calcium fluoride crystals by a focused femtosecond laser,” Opt. Express 12, 742–46 (2004), http://www.opticsexpress.org/abstract.cfm?URI=OPEX-12-5-742 [CrossRef] [PubMed]

OCIS Codes
(140.3390) Lasers and laser optics : Laser materials processing
(140.7090) Lasers and laser optics : Ultrafast lasers
(160.2750) Materials : Glass and other amorphous materials

ToC Category:
Research Papers

History
Original Manuscript: July 13, 2004
Revised Manuscript: August 11, 2004
Published: August 23, 2004

Citation
Quan-Zhong Zhao, Jian-Rong Qiu, Xiong-Wei Jiang, Chong-Jun Zhao, and Cong-Shan Zhu, "Controllable precipitation and dissolution of silver nanoparticles in ultrafast laser pulses irradiated Ag+-doped phosphate glass," Opt. Express 12, 4035-4040 (2004)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-12-17-4035


Sort:  Journal  |  Reset  

References

  1. K. Miura, J. Qiu, H. Inouye, T. Mitsuyu, and K. Hirao, �??Photowritten optical waveguides in various glasses with ultrashort pulse laser,�?? Appl. Phys. Lett. 71, 3329-31 (1997). [CrossRef]
  2. A. M. Streltsov and N. F. Borrelli, �??Fabrication and analysis of a directional coupler written in glass by nanojoule femtosecond laser pulses,�?? Opt. Lett. 26, 42-43 (2001). [CrossRef]
  3. K. Minoshima, A. M. Kowalevicz, I. Hartl, E. P. Ippen, and J. G. Fujimoto, �??Photonic device fabrication in glass by use of nonlinear materials processing with a femtosecond laser oscillator,�?? Opt. Lett. 26, 1516-18 (2001). [CrossRef]
  4. H. Sun, Y. Xu, S. Juodkazis, K. Sun, M. Watanabe, S. Matsuo, H. Misawa, and J. Nishii, �??Arbitrary-lattice photonic crystals created by multiphoton microfabrication,�?? Opt. Lett. 26, 325-27 (2001). [CrossRef]
  5. E. N. Glezer, M. Milosavljevic, L. Huang, R. J. Finlay, T.-H. Her, J. P. Callan, and E. Mazur, �??Three-dimensional optical storage inside transparent materials,�?? Opt. Lett. 21, 2023-25 (1996). [CrossRef] [PubMed]
  6. K. Miura, J. Qiu, S. Fujiwara, S. Sakaguchi, and K. Hirao, �??Three-dimensional optical memory with rewriteable and ultrahigh density using the valence-state change of samarium ions,�?? Appl. Phys. Lett. 80, 2263-65 (2002). [CrossRef]
  7. M. Kaempfe, T. Rainer, K.-J. Berg, G. Seifert, and H. Graener, �??Ultrashort laser pulse induced deformation of silver nanoparticles in glass,�?? Appl. Phys. Lett. 74, 1200-02 (1999). [CrossRef]
  8. Y. Watanabe, G. Namikawa, T. Onuki, K. Nishio, and T. Tsuchiya, �??Photosensitivity in phosphate glass doped with Ag+ upon exposure to near-ultraviolet femtosecond laser pulses,�?? Appl. Phys. Lett. 78, 2125-27 (2001). [CrossRef]
  9. Y. Cheng, K. Sugioka, M. Masuda, K. Shihoyama, K. Toyoda, K. Midorikawa, �??Optical gratings embedded in photosensitive glass by photochemical reaction using a femtosecond laser,�?? Opt. Express 11, 1809-16 (2003), <a href="http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-15-1809">http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-15-1809</a> [CrossRef] [PubMed]
  10. J. Qiu, M. Shirai, T. Nakaya, J. Si, X. Jiang, C. Zhu, K. Hirao, �??Space-selective precipitation of metal nanoparticles inside glasses,�?? Appl. Phys. Lett. 81, 3040-42 (2002). [CrossRef]
  11. J. Qiu, X. Jiang, C. Zhu, M. Shirai, J. Si, N. Jiang, K. Hirao, �??Manipulation of gold nanoparticles inside transparent materials,�?? Angew. Chem. Int. Ed. 43, 2230-34 (2004). [CrossRef]
  12. T. Feldman and A. Treinin, �??Inorganic radicals trapped in glasses at room temperature. IV. Silver radicals in metaphosphate glass,�?? J. Chem. Phys. 47, 2754-58 (1967). [CrossRef]
  13. I. Tanahashi, M. Yoshida, Y. Manabe, and T. Tohda, �??Effects of heat treatment on Ag particle growth and optical properties in Ag/SiO2 glass composite thin films,�?? J. Mater. Res. 10, 362-65 (1995). [CrossRef]
  14. G. Mie, �??Beiträge zur optik trüber medien, speziell kolloidaler metallösungen,�?? Ann. Phys. 25, 377-445 (1908). [CrossRef]
  15. H. Kogelnik, �??Coupled wave theory for thick hologram gratings,�?? Bell Syst. Tech. J. 48, 2909-47 (1969).
  16. Q. Z. Zhao, J. R. Qiu, X. W. Jiang, C. J. Zhao, C. S. Zhu, �??Fabrication of internal diffraction gratings in calcium fluoride crystals by a focused femtosecond laser,�?? Opt. Express 12, 742-46 (2004), <a href="http://www.opticsexpress.org/abstract.cfm?URI=OPEX-12-5-742">http://www.opticsexpress.org/abstract.cfm?URI=OPEX-12-5-742</a> [CrossRef] [PubMed]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited