在本文中，我們成功地利用雷射掃瞄式共焦顯微術，分別對摻鉻釔鋁石榴石晶體光纖、雙纖衣晶體光纖與玻璃光纖中的正三價與正四價鉻離子做螢光光譜檢測

In this study, we have successfully demonstrated the use of laser scanning confocal microscopy in studying the fluorescence spectroscopy of Cr3+ and Cr4+ ions in Cr:YAG crystal fibers, double-clad crystal fibers, and glass fibers.

Table of Contents
中文摘要……………………………………………………………………….. i
Abstract ……………………………………………………………………….. ii
Table of Contents ……………………………………………………………... iii
List of Tables…………………………………….…………………………….. iv
List of Figures…………………………………………………………….…… v
Chapter 1 Introduction……………………………………………………….. 1
Chapter 2 Properties of Cr:YAG crystal fiber….…..……………………… 3
2.1 General introduction for transition ions…………………………………. 3
2.1.1 Coordination and crystal field…………………………………….….. 5
2.1.2 Crystal field effect on Cr3+ energy level……………………………… 7
2.1.3 Crystal field effect on Cr4+ energy level……………………………… 10
2.2 Properties of Cr:YAG crystal…………………………………………..... 14
2.3 Fabrication and measurement for Cr:YAG crystal fiber………………… 18
2.3.1 LHPG system and fabrication processes.……………………………... 18
2.3.2 Sample preparation……………...…………………………………... 21
2.3.3 Refractive index measurement…...…………………………………... 23
2.3.4 Laser scanning confocal microscopy………...….…………………….. 24
2.3.5 Fluorescence lifetime measurement………………………………….. 27
Chapter 3 Oxidation states of Cr in YAG crystal fibers……..……………... 29
3.1 Charge compensation for generation of Cr4+ ion…………………….….. 29
3.2 Composition and structure analysis……………………………………... 34
3.3 Oxidation states in Cr:YAG single crystal fiber………………………..... 38
3.3.1 Doping concentrations in single crystal fiber…..……………………... 38
3.3.2 Fluorescence mappings of Cr3+ and Cr4+ ions in single crystal fiber…..... 41
3.3.3 The dependency between normalized Cr4+ and Ca2+…….…………...... 46
3.4 Oxidation states in Cr:YAG double-clad fiber…..……………………..... 48
3.4.1 Growth of double-clad fiber……………………..…………………... 48
3.4.2 Composition analysis and refractive index profile……………….…..... 50
3.4.3 Fluorescence mappings of Cr3+ and Cr4+ ions in double-clad fiber …...... 52
3.5 Cr4+ fluorescence lifetime and low temperature spectrum…………..…... 58
Chapter 4 Cr4+ enhancement by side deposition and annealing treatment.. 64
4.1 Side deposition by E-beam coater………………………...………...…… 64
4.1.1 Side deposition of Cr2O3………………….…..…………………..…. 67
v
4.1.2 Side deposition of CaO……..…………….…..……………………... 69
4.1.3 Side deposition of MgO…….…………….…..…………………..…. 74
4.2 Effects of annealing temperature and atmosphere………..…………..…. 78
Chapter 5 Cr ions in YAG-silica interdiffusion layer……..…………….….. 84
5.1 The nanocrystal in YAG-silica interdiffusion layer……………...…..….. 84
5.2 Compositional dependence Cr3+ and Cr4+ fluorescence spectra……..….. 87
5.3 400-nm-broadband emission from a Cr-doped glass fiber………………. 94
5.3.1 Fabrication process and composition analysis…….………………..…. 94
5.3.2 Propagation loss and absorption spectrum.…..……………………….. 96
5.3.3 Emission spectrum and amplified spontaneous emission power…….…. 98
Chapter 6 Conclusions…………...………..………………………………..… 103
References ………………………………………………..……………………. 106
Biography ………………………………………………..…………………….. 114
Publication List……………………………………………..………………….. 115
vi
List of Tables
Table 2.1 Crystal field parameters for Cr3+ ion in several laser host crystals… 9
Table 2.2 The spectral characteristics of Cr4+-doped crystals.…...…….……... 13
Table 2.3 Criteria for laser materials……………………….…………………. 14
Table 2.4 Physical and optical properties of Cr4+:YAG crystal………..……… 17
Table 2.5 SiC grit size (USA)………………………………………………… 21
Table 2.6 The mechanical preparation of crystal fiber samples………………. 22
Table 3.1 Comparison of ionic radii mismatch between dopant and host
cations……………………………………………………………….32
Table 3.2 Fluorescence characteristics of Cr:YAG and Cr,Ca:YAG crystal
fibers………………………………………………………………...33
Table 3.3 Physical properties of fused-silica glass…………………..………... 48
Table 3.4 The comparisons of lattice constant, zero phonon (λzp), and phonon
(λp) lines in bulk crystal, 70-μm crystal fiber, and core of DCF……63
Table 4.1 The dopant concentrations of 66-μm crystal fiber made from 2000
μm and 500 μm source materials…………………………………...65
Table 4.2 The functional dependence between Ca and Cr concentration…….. 70
Table 4.3 The functional dependence between Mg and Cr concentration……. 76
Table 4.4 The brightness intensity of dark field image with as grown and
annealing crystal fibers……………………………………………...77
Table 4.5 The comparison of lattice mismatch between host ions and charge
compensators………………………………………………………..77
Table 4.6 The relation between Cr, + 3
o Cr , + 4
o Cr , and + 4
t Cr ions………...…. 82
Table 4.7 The relation between Ca, + 4
o Cr , + 4
t Cr , and •
- 2 O V ions…………... 83
Table 5.1 Multi-peak Gaussian fittings of absorption spectra………………… 97
Table 5.2 Fluorescence spectra in different positions of core of Cr4+-doped
glass fiber…………………………………………………………...102
vii
List of Figures
Fig. 2.1 Crystal field parameters for Cr3+ ion in several laser host crystals… 4
Fig. 2.2 Single configuration coordinate diagram of a transition-metal ion
coupled to a vibrating lattice………………………………………..6
Fig. 2.3 Configuration coordinated diagram of the ground state 4A2 and
excited states 2E and 4T2 of Cr3+-doped solids……………………...7
Fig. 2.4 Energy-level diagram as a function of the crystal field strength in
units of Racah parameter B for the octahedrally coordinated d3
system (such as Cr3+)………………………………………………..8
Fig. 2.5 Fluorescence spectra for Cr3+ ion in several laser host crystals……. 9
Fig. 2.6 Energy-level diagram as a function of the crystal field strength in
units of Racah parameter B for the octahedrally coordinated d2
system (such as Cr4+)………………………………………………..11
Fig. 2.7 Electronic energy levels of Cr4+ ion in Td symmetry, showing the
splittings introduced by a D2d distortion and spin-orbital coupling...11
Fig. 2.8 10K absorption spectrum of Cr4+:YAG. The inset shows an
enlargement of the lowest-energy transition………………………..12
Fig. 2.9 The garnet structure………………………………………………… 15
Fig. 2.10 (a) Absorption and (b) fluorescence spectra of Cr4+:YAG.
Fluorescence spectrum was taken under Nd:YAG laser with
wavelength at 1.06 μm……………………………………………...16
Fig. 2.11 Energy level diagram of the Cr4+:YAG crystal……………………... 17
Fig. 2.12 The LHPG system………………………………………………….. 19
Fig. 2.13 Growth chamber…………………………………………………….19
Fig. 2.14 Illustration of single crystal growth by LHPG method…………….. 20
Fig. 2.15 Photography of a 70-μm-diameter crystal fiber of Cr4+:YAG……… 20
Fig. 2.16 The revolution of surface quality after grinding and polishing…….. 22
Fig. 2.17 Refractive index measurement setup……………………………….. 23
Fig. 2.18 The fluorescence spectra of (a) Cr3+ and (b) Cr4+ in YAG…………. 24
Fig. 2.19 Laser scanning confocal microscope setup………………………… 26
Fig. 2.20 The transmittance spectra of (a) Cr3+ and (b) Cr4+ dichroic beam
splitters……………………………………………………………...26
Fig. 2.21 Measurement setup for Cr4+ fluorescence lifetime…………………. 27
Fig. 2.22 The modulated laser power at 3 kHz……………………………….. 28
Fig. 2.23 The fall time of system response…………………………………… 28
Fig. 3.1 Configuration of the Cr ions in YAG structure…………………….. 30
Fig. 3.2 The Cr3+ and Cr4+ absorption spectra in YAG……………………… 31
viii
Fig. 3.3 (a) Photograph of line scanning marks on the cross section of
crystal fiber. (b) The distribution of Y2O3 and Al2O3 in YAG crystal
fiber…………………………………………………………………34
Fig. 3.4 Refractive index profile of crystal fiber with Pyrex glass cladding... 35
Fig. 3.5 The power fluctuation of DFB laser………………………………... 36
Fig. 3.6 The normalized X-ray diffraction patterns of Cr4+:YAG crystal
grown by CZ and LHPG methods…………………………………..37
Fig. 3.7 Doping profiles of (a) Cr2O3 and (b) CaO in different diameter
crystal fibers with different diameters………………………………39
Fig. 3.8 The average concentrations of Cr2O3 and CaO in fiber with various
diameters……………………………………………………………40
Fig. 3.9 (a) Side view of Cr:YAG crystal fiber. (b) The micron-sized
particles formed at the surface of crystal fiber……………………...40
Fig. 3.10 SEM side view SEI and EDX mappings of Cr:YAG crystal fiber
showing wide distribution of micron-sized Cr-rich particles on the
surface………………………………………………………………40
Fig. 3.11 The Cr3+ and Cr4+ fluorescence mappings of crystal fibers with
various diameters……………………………………………………
41
Fig. 3.12 Comparison between LSCM and EPMA measurements for (a) 920
μm and (b) 300 μm crystal fibers…………………………………...42
Fig. 3.13 The absorption spectrum of Cr4+:YAG with α of 4.5 cm-1 at 1064
nm…………………………………………………………………...43
Fig. 3.14 The distributions of (a) Cr3+ and (b) Cr4+ with various diameter
crystal fibers measured by LSCM…………………………………..44
Fig. 3.15 The concentrations of Cr3+ and Cr4+ ions in various diameter
crystal fibers………………………………………………………...45
Fig. 3.16 The distributions of Cr4+, Cr2O3, and CaO concentrations in (a)
920-μm- diameter and (b) 66-μm-diameter crystal fibers…………..46
Fig. 3.17 The dependence between normalized Cr4+ and Ca2+ concentrations.. 47
Fig. 3.18 Left: Schematic diagram of the molten zone during growth, right:
photograph of the side view of the grown double-clad Cr4+:YAG
fiber…………………………………………………………………49
Fig. 3.19 The SEM image of double-clad fiber end view……………………. 50
Fig. 3.20 Compositions of double-clad fiber and its refractive index profile… 51
Fig. 3.21 Cr3+ fluorescence intensity mapping……………………………….. 52
Fig. 3.22 Distribution of Cr2O3 concentration and Cr3+ fluorescence intensity. 53
Fig. 3.23 Cr3+ fluorescence spectra at DCF core and inner cladding………… 53
Fig. 3.24 Cr4+ fluorescence intensity mapping……………………………….. 54
Fig. 3.25 Distribution of CaO concentration and Cr4+ fluorescence intensity... 54
ix
Fig. 3.26 Cr4+ fluorescence spectra at DCF core and inner cladding………… 55
Fig. 3.27 The end view of DCF by Al and Cu diffusion to inner cladding…... 56
Fig. 3.28 The compositions of DCF by Al and Cu diffusion to inner cladding. 56
Fig. 3.29 The end views of DCF by Al and Cu diffusion into core…………... 56
Fig. 3.30 The Cr3+ and Cr4+ fluorescence intensity of DCF by Al and Cu
diffusion into (a) inner cladding and (b) core……………………….57
Fig. 3.31 The measured fall times of (a) bulk crystal, (b) 70-μm crystal fiber,
and (c) core of DCF…………………………………………………59
Fig. 3.32 (a) Appearance of hot and cold stage and (b) the cold zone of the
stage where a Cr:YAG crystal is inside……………………………60
Fig. 3.33 The Cr4+ fluorescence spectra with temperature from 300K to 88K. 61
Fig. 3.34 The Cr4+ fluorescence spectra of bulk crystal, 70-μm crystal fiber,
and core of DCF with temperature at 88K………………………….62
Fig. 3.35 HRTEM images and diffraction patterns of (a) bulk crystal and (b)
core of DCF…………………………………………………………62
Fig. 4.1 The relation of ASE power with Cr4+ concentration and fiber length 64
Fig. 4.2 Schemes of side deposition by E-beam coater, and the LHPG
growth thereafter……………………………………………………66
Fig. 4.3 The relation between Cr2O3 deposition time and thickness………... 67
Fig. 4.4 The relation between Cr2O3 deposition thickness on the source
material and concentration of the crystal fiber with 66 μm in
diameter……………………………………………………………..68
Fig. 4.5 The relation between CaO deposition time and thickness…………. 70
Fig. 4.6 The relation between CaO deposition thickness and concentration
on crystal fiber with 66 μm in diameter…………………………….70
Fig. 4.7 The functional dependence between normalized Cr4+ and Ca2+
concentration………………………………………………………..71
Fig. 4.8 The (a) bright field and (b) dark field images of the crystal fiber….. 71
Fig. 4.9 Environment furnace……………………………………………….. 72
Fig. 4.10 Annealing sequences……………………………………………….. 72
Fig. 4.11 The (a) bright field and (b) dark field images of crystal fiber after
annealing at 1350oC under oxygen atmosphere…………………….73
Fig. 4.12 The functional dependence between normalized Cr4+ and Ca2+
concentrations after annealing at 1350oC under oxygen atmosphere.
73
Fig. 4.13 The dependence between MgO deposition time and thickness…….. 74
Fig. 4.14 The relation between MgO deposition thickness and concentration
on crystal fiber with 66 μm in diameter…………………………….74
Fig. 4.15 The functional dependence between normalized Cr4+ and Mg2+…... 76
x
Fig. 4.16 The bright (upper row) and dark (lower row) field images of MgO
side deposition crystal fiber…………………………………………76
Fig. 4.17 The bright (upper row) and dark (lower row) field images of MgO
side deposition crystal fibers after 1350oC annealing under oxygen
atmosphere………………………………………………………….77
Fig. 4.18 The Cr4+ fluorescence intensity with different annealing
temperatures under nitrogen and oxygen atmospheres with 4 hours
annealing time………………………………………………………78
Fig. 4.19 The simplified Cr4+ fluorescence intensity diagram with different
annealing temperatures under nitrogen and oxygen atmospheres…..79
Fig. 4.20 The Cr3+ fluorescence intensity with different annealing
temperatures under nitrogen and oxygen atmospheres with 4 hours
annealing time………………………………………………………80
Fig. 4.21 The simplified Cr3+ fluorescence intensity diagram with different
annealing temperatures under nitrogen and oxygen atmospheres…..80
Fig. 5.1 The TEM image in inner cladding and outer cladding interface…... 85
Fig. 5.2 The TEM image in inner cladding…………………………………. 85
Fig. 5.3 The HRTEM image of crystalline nano-structures………………… 86
Fig. 5.4 The SAED pattern showing hkl diffractions, as indexed…………... 86
Fig. 5.5 Cr3+ fluorescence spectrum at DCF inner cladding, which is fitted
by Gaussian profiles………………………………………………...88
Fig. 5.6 Cr3+ fluorescence spectra associated with different positions in
inner cladding, corresponding to various concentrations of SiO2…..89
Fig. 5.7 Five Gaussian-peak-fitted curves for Cr3+ fluorescence spectra with
various concentrations of SiO2……………………………………...89
Fig. 5.8 The emission intensity ratio of Cr3+ in HFS to LFS with different
SiO2 concentration…………………………………………………..90
Fig. 5.9 Cr4+ fluorescence spectrum at DCF inner cladding, which is fitted
by Gaussian profiles………………………………………………..91
Fig. 5.10 Cr4+ fluorescence spectra associated with different positions in
inner cladding, corresponding to various concentrations of SiO2…..92
Fig. 5.11 Seven Gaussian-peak-fitted curves for Cr4+ fluorescence spectra
with various concentrations of SiO2………………………………...92
Fig. 5.12 The emission intensity ratio of Cr3+ in HFS to LFS with different
SiO2 concentration…………………………………………………..93
Fig. 5.13 The end view of Cr4+-doped glass fiber……………………………. 95
Fig. 5.14 The distributions of host compositions by EPMA measurement…... 95
xi
Fig. 5.15 (a) The absorption spectra of samples 1, 2, and 3. (b), (c), and (d)
show the multi-peak Gaussian fitting of samples 1, 2, and 3,
respectively…………………………………………………………97
Fig. 5.16 The emission spectra of (a) sample 1, (b) sample 2, and (c) sample
3 under the pumping wavelengths from 750 nm to 1000 nm……….99
Fig. 5.17 Pumping wavelength dependence of emission peaks and
bandwidths in the sample 2…………………………………………100
Fig. 5.18 Curve fitting for 406-nm-bandwidth emission……………………... 100
Fig. 5.19 Fig. 5.19 Fluorescence spectra in (a) center-, (b) middle-, and (c)
edge-positions of core of Cr4+-doped glass fiber……………………101
Fig. 5.20 The measured ASE output power of sample 2. The inset is the
fluorescence spectrum by 900-nm pumping wavelength with a 950
nm long-wavelength-pass filter to block the pump beam…………..102

[1.1] E. Desurvire, J. R. Simpson, and P. C. Becker, “High-gain erbium-doped traveling-wave fiber amplifier,” Optics Letters 12, 888 (1987).
[1.2] J. F. Massicott, J. R. Armitage, R. Wyatt, B. J. Ainslie, and S. P. Craig-Ryan, “High gain, broadband, 1.6 μm Er3+ doped silica fiber amplifier,” Electronics Letters 26, 1645 (1990).
[1.3] T. Komukai, T. Yamamoto, T. Sugawa, and Y. Miyajima, “1.47 μm band Tm3+ doped fluoride fiber amplifier using a 1.064 μm upconversion pumping scheme,” Electronics Letters 29, 110 (1993).
[1.4] Y. Ohishi, T. Kanamori, T. Kitagawa, S. Takahashi, E. Snitzer, and G. H. Sigel, Jr., “Pr3+-doped fluoride fiber amplifier operating at 1.31 μm,” Optics Letters 16, 1747 (1991).
[1.5] C. Batchelor, W. J. Chung, S. Shen, and A. Jha, “Enhanced room-temperature emission in Cr4+ ions containing alumino-silicate glasses,” Applied Physics Letters 82, 4035 (2003).
[1.6] S. Tanabe and X. Feng, “Temperature variation of near-infrared emission from Cr4+ in aluminate glass for broadband telecommunication,” Applied Physics Letters 77, 818 (2000).
[1.7] X. Feng and S. Tanabe, “Spectroscopy and crystal-field analysis for Cr(IV) in alumino-silicate glasses,” Optical Materials 20, 63 (2002).
[1.8] V. Felice, B. Dussardier, J. K. Jones, G. Monnom, and D. B. Ostrowsky, “Chromium-doped silica optical fibres: influence of the core composition on the Cr oxidation states and crystal field,” Optical Materials 16, 269 (2001).
[1.9] B. Lipavsky, Y. Kalisky, Z. Burshtein, Y. Shimony, and S. Rotman, “Some optical properties of Cr4+-doped crystals,” Optical Materials 13, 117 (1999).
[1.10] C. Y. Lo, K. Y. Huang, J. C. Chen, S. Y. Tu, and S. L. Huang, “Glass-clad Cr4+:YAG crystal fiber for the generation of superwideband amplified spontaneous emission,” Optics Letters 29, 439 (2004).
[1.11] C. Y. Lo, K. Y. Huang, J. C. Chen, C. Y. Chuang, C. C. Lai, S. L. Huang, Y. S. Lin, and P. S. Yeh, “Double-clad Cr4+:YAG crystal fiber amplifier,” Optics Letters 30, 129 (2005).
[2.1] J. E. Geusic, H. M. Marcos, and L. G. V. Uitert, “Laser oscillations in Nd-doped yttrium aluminum, yttrium gallium and gadolinium garnets,” Applied Physics Letters 4, 182 (1964).
[2.2] J. C. Walling, O. G. Peterson, H. P. Jenssen, R. C. Morris, and E. W. O’Dell, “Tunable alexandrite lasers,” IEEE Journal of Quantum Electronics 16, 1302 (1980).
[2.3] S. A. Payne, L. L. Chase, H. W. Newkirk, L. K. Smith, and W. F. Krupke, “LiCaAlF6:Cr3+: a promising new solid-state laser material,” IEEE Journal of Quantum Electronics 24, 2243 (1988).
[2.4] P. F. Moulton, “Spectroscopic and laser characteristics of Ti:Al2O3,” Journal of the Optical Society of America B: Optical Physics 3, 125 (1986).
[2.5] L. F. Johnson and H. J. Guggenheim, “Phonon-terminated coherent emission from V2+ ions in MgF2,” Journal of Applied Physics 38, 4837 (1967).
[2.6] V. G. Baryshevsky, M. V. Korzhik, M. G. Livshits, A. A. Tarasov, A. E. Kimaev, I. I. Mishkel, M. L. Meilman, B. J. Minkov, and A. P. Shkadarevich, “Properties of forsterite and performance of forsterite lasers with lasers and flashlamp pumping,” OSA Proceedings on Advanced Solid-State Lasers 10, 26 (1991).
[2.7] S. Kück, J. Koetke, K. Petermann, U. Pohlmann, and G. Huber, “Spectroscopic and laser studies of Cr4+:YAG and Cr4+:Y2SiO5,” OSA Proceedings on Advanced Solid-State Lasers 15, 334 (1993).
[2.8] L. F. Johnson, H. J.Guggenheim, and R. A. Thomas, “Phonon-terminated optical masers,” Physical Review 149, 179 (1966).
[2.9] D. M. Rines, P. F. Moulton, D. Welford, and G. A. Rines, “High-energy operation of a Co:MgF2 laser,” Optics Letters 19, 628 (1994).
[2.10] G. J. Wagner, T. J. Carrig, R. H. Page, K. I. Schaffers, J. O. Ndap, X. Ma, and A. Burger, “Continuous-wave broadly tunable Cr:2+ ZnSe laser,” Optics Letters 24, 19 (1999).
[2.11] Y. Kalisky, “Cr4+-doped crystals: their use as lasers and passive Q-switches,” Progress in Quantum Electronics 28, 249 (2004).
[2.12] B. Henderson and G. F. Imbusch, “Optical spectroscopy of inorganic solids,” Clarendon, Oxford (1989).
[2.13] A. Sennaroglu, “Broadly tunable Cr4+-doped solid-state lasers in the near infrared and visible,” Progress in Quantum Electronics 26, 287 (2002).
[2.14] T. H. Maiman, “Stimulated optical radiation in ruby,” Nature 187, 493 (1960).
[2.15] Y. Tanabe and S. Sugano, “On the absorption spectra of complex ions,” Journal of Physical Society Japan 9, 753 (1954).
[2.16] S. Sugano and Y. Tanabe, and H. Kamimura, “Multiplets of transition-metal ions in crystals,” Academic, New York (1970).
[2.17] R. C. Powell, “Physics of solid-state laser materials,” Springer, New York (1997).
[2.18] B. Struve and G. Huber, “The effect of the crystal field strength on the optical spectra of Cr3+ in gallium garnet laser crystals,” Applied Physics B: Photophysics and laser chemistry 36, 195 (1985).
[2.19] Z. Zhang, K. T. V. Grattan, and W. Palmer, “Temperature dependences of fluorescence lifetime in Cr3+-doped insulating crystals,” Physical Review B 48, 7772 (1993).
[2.20] P. Kisliuk and C. A. Moore, “Radiation from the 4T2 state of Cr3+ in Ruby and Emerald,” Physical Review 160, 307 (1967).
[2.21] W. A. Wall, J. T. Karpick, and B. D. Bartolo, “Temperature dependence of the vibronic spectrum and fluorescence lifetime of YAG:Cr3+,” Journal of Physics C: Solid State Physics 4, 3258 (1971).
[2.22] B. E. Douglas, “Symmetry in bonding and spectra,” Academic, Orlando (1985).
[2.23] H. Eilers, U. Hömmerich, S. M. Jacobsen, and W. M. Yen, “Spectroscopy and dynamics of Cr4+:Y3Al5O12,” Physical Review B 49, 15505 (1994).
[2.24] B. Henderson, H. G. Gallagher, T. P. J. Han, and M. A. Scott, “Optical spectroscopy and optimal crystal growth of some Cr4+-doped garnets,” Journal of Physics: Condensed Matter 12, 1927 (2000).
[2.25] S. Kück, K. Petermann, U. Pohlmann, and G. Huber, “Electronic and vibronic transitions of the Cr4+-doped garnets Lu3Al5O12, Y3Al5O12, Y3Ga5O12 and Gd3Ga5O12,” Journal of Luminescence 68, 1 (1996).
[2.26] C. Deka, M. Bass, B. H. T. Chai, and Y. Shimony, “Optical spectroscopy of Cr4+:Y2SiO5,” Journal of the Optical Society of America B: Optical Physic 10, 1499 (1993).
[2.27] R. Moncorge, D. J. Simkin, G. Cormier, and J. A. Capobianco, “Spectroscopic properties and fluorescence dynamics in chromium-doped forsterite,” OSA Proceedings on Tunable Solid-State Lasers 5, 93 (1989).
[2.28] S. Kück, K. Petermann, U. Pohlmann, and G. Huber, “Near-infrared emission of Cr4+-dopeped garnets: lifetimes, quantum efficiencies, and emission cross sections,” Physical Review B: Condensed Matter 51, 17323 (1995).
[2.29] M. F. Hazenkamp, H. U. Güdel, M. Atanasov, U. Kesper, and D. Reinen, “Optical spectroscopy of Cr4+-doped Ca2GeO4 and Mg2SiO4,” Physical Review B 53, 2367 (1996).
[2.30] H. Eilers, W. M. Dennis, W. M. Yen, S. Kück, K. Peterman, G. Huber, and W. Jia, “Performance of a Cr:YAG laser,” IEEE Journal of Quantum Electronics 29, 2508 (1993).
[2.31] S. B. Ubiszkii, S. S. Melnyk, B. V. Padlyak, A. O. Matkovskii, A. J.-Frydel, and Z. Frukacz, “Chromium recharging processes in the Y3Al5O12: Mg, Cr single crystal under the reducing and oxidizing annealing influence,” Proceedings of SPIE 4412, 63 (2001).
[2.32] S. Kück, “Laser-related spectroscopy of ion-doped crystal for tunable solid-state lasers,” Applied Physics B: Lasers and Optics 72, 515 (2001).
[2.33] S. Kück, U. Pohlmann, K. Petermann, G. Huber, and T. Schonherr, “High resolution spectroscopy of Cr4+ doped Y3Al5O12,” Journal of Luminescence 60-61, 192 (1994).
[2.34] A. Sugimoto, Y. Nobe, and K. Yamagishi, “Crystal growth and optical characterization of Cr,Ca:Y3Al5O12,” Journal of Crystal Growth 140, 349 (1994).
[2.35] S. Fukaya, K. Adachi, M. Obara, and H. Kumagai, “The growth of Cr4+:YAG and Cr4+:GGG thin films by pulsed laser deposition,” Optics Communications 187, 373 (2001).
[2.36] S. Ishibashi, K. Naganuma, and I. Yokohama, “Cr,Ca:Y3Al5O12 laser crystal grown by the laser-heated pedestal growth method,” Journal of Crystal Growth 183, 614 (1998).
[2.37] C. Y. Lo, “Growth, characterization, and application of doped-YAG single-crystal fibers,” PhD dissertation, Taiwan (2004).
[2.38] J. B. Pawley, “Handbook of Biological Confocal Microscopy 2nd edition”, Plenum Press, New York (1995).
[2.39] K. Konig, “Multiphoton microscopy in life sciences,” Journal of Microscopy 200, 83 (2000).
[2.40] W. Denk, J. H. Strickler, and W. W. Webb, “Two-photon laser scanning fluorescence microscopy,” Science 248, 73 (1990).
[2.41] J. P. Hehir, M. O. Henry, J. P. Larkin and G. F. Imbusch, “Nature of the luminescence from YAG:Cr3+,” Journal of Physics C: Solid State Physics 7, 2241 (1974).
[3.1] V. Petričević, S. K. Gayen, R. R. Alfano, K. Yamagishi, H. Anzai, and Y. Yamaguchi, “Laser action in chromium-doped forsterite,” Applied Physics Letters 52, 1040 (1998).
[3.2] H. R. Verdun, L. M. Thomas, D. M. Andrauskas, T. McCollum, and A. Pinto, “Chromium-doped forsterite laser pumped with 1.06 µm radiation,” Applied Physics Letter 53, 2593 (1988).
[3.3] R. Moncorge, G. Cormier, D. J. Simkin, and J. A. Capobianco, “Fluorescence analysis of chromium-doped forsterite (Mg2SiO4),” IEEE Journal of Quantum Electronics 27, 114 (1991).
[3.4] U. Hömmerich, H. Eilers, S. M. Jacobsen, and W. M. Yen, “Near infrared luminescence properties of the laser material Cr:Y2SiO5,” Journal of Luminescence 55, 293 (1993).
[3.5] J. Koetke, S. Kück, K. Petermann, G. Huber, G. Cerullo, M. Danailov, V. Magni, L. F. Qian, and O. Svelto, “Quasi-continuous wave laser operation of Cr4+ doped Y2SiO5 at room temperature,” Optics Communications 101, 195 (1993).
[3.6] A. G. Okhrimchuk and A. V. Shestakov, “The local vibration absorption band in the YAG:Cr4+ crystal,” in J. J. Jayhoswski (Ed.), OSA Trends in Optics and Photonics (TOPS), Advanced Solid-State Photonics 83, 224 (2003).
[3.7] A. G. Okhrimchuk and A. V. Shestakov, “Performance of YAG:Cr4+ laser crystal,” Optical Materials 3, 1 (1994).
[3.8] S. B. Ubizskii, S. S. Melnyk, B. V. Padlyak, A. O. Matkovskii, A. Jankowska-Frydel, and Z. Frukacz, “Chromium recharging processes in the Y3Al5O12:Mg, Cr single crystal under the reducing and oxidizing annealing influence,” Proceeding of SPIE 4412, 63 (2001).
[3.9] S. A. Markgraf, M. F. Pangborn, and R. Dieckmann, “Influence of different divalent co-dopants on the Cr4+ content of Cr-doped Y3Al5O12,” Journal of Crystal Growth 180, 81 (1997).
[3.10] http://www.webelements.com.
[3.11] B. M. Tissue, W. Jia, L. Lu, and W. M. Yen, “Coloration of chromium-doped yttrium aluminum garnet single-crystal fibers using a divalent codopant,” Journal of Applied Physics 70, 3775 (1991).
[3.12] W. Eickhoff and E. Weidel, “Measuring method for the refractive index profile of optical glass fibres,” Optical and Quantum Electronics 7, 109 (1975).
[3.13] A. E. Nosenko and L. V. Kostyk, “Valence state of dopant chromium ions in calcium-gallium-germanium garnet crystals,” Journal of Applied Spectroscopy 58, 413 (1994).
[3.14] D. C. Koningsberger and R. Prins, “X-ray Absorption: Principle, Application, Techniques of EXAFS, SEXAFS and XANES,” Wiley, New York (1988).
[3.15] D. Jun, D. Peizhen, and X. Jun, “The growth of Cr4+, Yb3+: yttrium aluminum garnet (YAG) crystal and its absorption spectra properties,” Journal of Crystal Growth 203, 163 (1999).
[3.16] N. I. Borodin, V. A. Zhitnyuk, A. G. Okhrimchuk, and A. V. Shestakov, “Oscillation of an Y3Al5O12:Cr4+ laser in the wavelength region of 1.35-1.6 μm,” Bulletin of the Academy of Sciences of the USSR Physical Series 54, 54 (1990).
[3.17] http://www.udel.edu/chem/GlassShop.
[3.18] B. Henderson, M. Yamaga, Y. Gao, and K. P. O’Donnell, “Disorder and nonradiative decay of Cr3+-doped glasses,” Physical Review B 46, 652 (1992).
[3.19] T. Murata, M. Torisaka, H. Takebe, and K. Morinaga, “Compositional dependence of the valency state of Cr ions in oxide glasses,” Journal of Non-Crystalline Solids 220, 139 (1997).
[3.20] W. Jia, H. Liu, S. Jaffe, and W. M. Yen, “Spectroscopy of Cr3+ and Cr4+ ions in forsterite,” Physical Review B 43, 5234 (1991).
[5.1] J. M. McHale, A. Auroux, A. J. Perrotta, and A. Navrotsky, “Surface energies and thermodynamic phase stability in nanocrystalline aluminas,” Science 277, 788 (1997).
[5.2] W. Hu and G. Gottstein, “Investigation of microstructure and chemical stability in composites of Ni3Al reinforced bt alumina-silica fibers,” Material Science and Engineering A 338, 313 (2002).
[5.3] Y. R. Shen and K. L. Bray, “Effect of pressure and temperature on the lifetime of Cr3+ in yttrium aluminum garnet,” Physical Review B 56, 10882 (1997).
[5.4] M. Yamaga, B. Henderson, and K. P. O’Donnell, “Line shape of the Cr3+ luminescence in garnet crystals,” Physical Review B 46, 3273 (1992).
[5.5] X. Wu, S. Huang, U. Hömmerich, W. M. Yeh, B. G. Aitken, and M. Newhouse, “Spectroscopy of Cr4+ in MgCaBa aluminate glass. The coupling of 3T2 and 1E states,” Chemical Physics Letters 233, 28 (1995).
[5.6] R. Miletich, D. R. Allan, and W. F. Kuhs, “High-pressure single-crystal techniques,” Ch. 14 in “High-temperature and high-pressure crystal chemistry,” (eds. R.M. Hazen and R.T. Downs), Mineralogical Society of America, Washington DC, 445 (2000).
[5.7] A. F. Fercher, W. Drexler, C. K. Hitzenberger, and T. Lasser, “Optical coherence tomography-principles and applications,” Reports on Progress in Physics 66, 239 (2003).
[5.8] V. Felice, B. Dussardier, J. K. Jones, G. Monnom, and D. B. Ostrowsky, “Cr4+-doped silica optical fibres: absorption and fluorescence properties,” The European Physical Journal Applied Physics 11, 107 (2000).
[5.9] V. V. Dvoyrin, E. M. Dianov, V. M. Mashinsky, V. B. Neustruev, A. N. Guryanov, A. Y. Laptev, A. A. Umnikov, M. V. Yashkov, and N. S. Vorobiev, “Absorption and luminescence properties of Cr4+-doped silica fibres,” Quantum Electronics 31, 996 (2001).
[5.10] V. V. Dvoyrin, V. M. Mashinsky, V. B. Neustruev, E. M. Dianov, A. N. Guryanov, and A. A. Umnikov, “Effective room-temperature luminescence in annealed chromium-doped silicate optical fibers,” Journal of the Optical Society of America B 20, 280 (2003).