3 dimenstional microstructural fabrication of foturanTM glass with femtosecond laser irradiation

3-DIMENSIONAL MICROSTRUCTURAL FABRICATION OF FOTURANTM GLASS WITH FEMTOSECOND LASER IRRADIATION TEO HONG HAI NATIONAL UNIVERSITY OF SINGAPORE 2009 3-DIMENSTIONAL MICROSTRUCTURAL FABRICATION OF FOTURANTM GLASS WITH FEMTOSECOND LASER IRRADIATION TEO HONG HAI (B. Eng. (Hons.), Nanyang Technological University) A THESIS SUBMITTED FOR THE DEGREE OF MASTER OF ENGINEERING DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2009 Acknowledgement  ACKNOWLEDGEMENTS I would like to take this opportunity to express my appreciation to my supervisor, Associate Professor Hong Minghui for his guidance during the entire period of my Masters studies. He has been encouraging particularly in trying times. His suggestions and advice were very much valued. I would also like to express my gratitude to all my fellow co-workers from the DSI-NUS Laser Microprocessing Lab for all the assistance rendered in one way or another. Particularly to Caihong, Tang Min and Zaichun for all their encouragement and assistance as well as to Huilin for her support in logistic and administrative issues. Special thanks to my fellow colleagues from Data Storage Institute (DSI), in particular, Doris, Kay Siang, Zhiqiang and Chin Seong for all their support. To my family members for their constant and unconditioned love and support throughout these times, without which, I will not be who I am today. i Table of Contents  TABLE OF CONTENTS ACKNOWLEDGEMENTS i TABLE OF CONTENTS ii SUMMARY v LIST OF FIGURES viii LIST OF SYMBOLS x LIST OF PUBLICATIONS xi CHAPTER INTRODUCTION 1.1 General Background 1.2 Recent Progress in Photosensitive Glass and Femtosecond Laser Microprocessing 1.3 Limitations of Conventional Glass and Challenges on Laser Microprocessing Techniques of Glass Substrates 1.4 Fabrication by Femtosecond Laser on FoturanTM Glass 12 1.5 Research Objectives and Contributions 17 1.5.1 Fabrication of a Monolithic 2-level 3-dimensional Micro-mixer 17 1.5.2 Optimization of a Monolithic 2-level 3-dimensional Micro-mixer 18 1.6 Thesis Outline 20 ii Table of Contents  CHAPTER THEORETICAL BACKGROUND 2.1 2.2 Multi-photon Absorption by Photosensitive Glass 27 2.1.1 31 Mechanism during Thermal Annealing of Photosensitive Glass under Femtosecond Laser Irradiation 35 Reactions Involved during Thermal Annealing of FoturanTM Glass after Laser Exposure 35 Chemical Reactions during Wet Chemical HF etching of Photosensitive Glass under Femtosecond Laser Irradiation 38 2.2.1 2.3 Photosensitive Glass under Femtosecond Laser Irradiation CHAPTER EXPERIMENTAL SETUP 3.1 3.2 Femtosecond Laser Fabrication of Microstructures In-situ of FoturanTM Glass 44 3.1.1 Introduction 44 3.1.2 Experimental Setup of Femtosecond Laser Irradiation of FoturanTM Glass 46 3.1.3 Application of the Femtosecond Laser 48 3.1.4 Thermal Annealing Cycle and Wet Chemical Etching 50 Characterization Techniques for the Monolithic 2-level 3D Internal Micromixer 51 3.2.1 51 Optical Microscopy 3.2.2 JEOL JSM 7401F Scanning Electron Microscopy (SEM) 54 3.2.3 56 3D Surface Profilometry 3.2.5 Characterizing the Mixing Capability of the Fabricated Micro-mixer 58 iii Table of Contents  CHAPTER 3-DIMENSIONAL MICROSTRUCTURAL FABRICATION BY FEMTOSECOND LASER MICROPROCESSING 4.1 Fabrication Process Flow 62 4.1.1 Sample Preparation 64 4.1.2 Multi-Photon Absorption 66 4.1.3 Principles of Two-Photon Excitation 69 4.2 Thermal Annealing 71 4.3 Etching 72 4.3.1 77 4.4 Isotropy / Anisotropy 4.3.2 Selectivity 79 Characterizing the 2-level 3D Internal Micro-mixer 79 CHAPTER RESULTS AND DISCUSSION 5.1 Introduction 88 5.2 Influence of Laser Irradiation 91 5.3 Influence of Thermal Cycling 99 5.4 Influence of Wet Chemical Etching 102 5.5 Design Optimization 104 CHAPTER CONCLUSIONS 6.1 Conclusions 112 6.2 Suggestions for Future Work 115 iv Summary  SUMMARY Fabrication of real 3-dimensional (3D) microstructures embedded inside a monolithic FoturanTM glass is a very attractive and promising technology in the field of life sciences and biotechnology. It offers a wide range of opportunities and opens up many potential applications in the studies of photonics, medicine as well as aerospace engineering. This technique exploits the unique optical, chemical and physical properties of microstructuring inside glass. The research reported in this thesis primarily aims to fabricate real 3D microstructures, achieves multiple micro-channels and multi-level connectivity as well as to investigate the process optimization by making use of different methods and varying different parameters. Currently, the difficulties of fabricating microstructures inside glass are evident in the wide variety of non-conventional techniques employed. The most commonly used approach in glass patterning is based on conventional lithography, however, this technique is limited by slow etch rates with majority of the patterning performed on the surfaces of the samples. Micro-cracking and other collateral damages further introduce additional unnecessary stresses to the glass substrates. In addition, this approach has many limitations in numerous industrial applications attributing from the high cost of the masks, low throughput and the many tedious repeating steps. Therefore, our direct laser application, a fast and maskless technique, has been used in this thesis for the patterning and fabrication of micro-architectures and microstructures v Summary  inside the photosensitive glass, FoturanTM. This technique involves only a femtosecond laser and a axes X-Y-Z stage. Its main advantages lie in its low cost, high speed and being a simple operation. After the patterns are formed inside the FoturanTM glass, a thermal annealing cycle will follow and subsequent etching is employed to fabricate the required design of the microstructures. The utilization of femtosecond laser irradiation employs multi-photon absorption (MPA), which permits the fabrication of embedded intricate 3D microstructures and integrates all these complex microstructures within the material. This technique has the capability to create undercut and freestanding microstructures without resorting to ablation, thereby minimizing residual stresses as well as impending issues of surface morphology. These monolithic ‘all-in-one’ devices are highly desirable because of their potentials in meeting unique and individually customized requirements in various applications. In this thesis, a monolithic real 3D ‘allin-one’ analytical device with levels of micro-reservoirs and interconnecting microchannels was fabricated. The mixing capability of the device is demonstrated by mixing individual colored dyes to obtain a single homogeneous dye solution. The repeatability and reliability of the fabricated device were further demonstrated with further mixing of other dyes. Since FoturanTM glass is highly sensitive to the dosage of irradiation, exposure time, annealing temperature and time, etching concentration and time, the desired embedded microstructures have been achieved by varying these parameters. Different approaches were undertaken in order to optimize the mixing capability of the monolithic 2-level 3D embedded micro-mixer. First and foremost, the laser irradiation power was investigated and determined to eradicate the issue of surface ablation, an issue vi Summary  experienced by most international research groups. Subsequent process of thermal annealing time and temperature were further optimized to initiate the photo-chemical reaction. Insufficient heating does not initiate the nucleation and agglomeration process while extended heating will result in the warpage of the FoturanTM glass, which has a major detrimental effect towards the etching process. The etching times were also affected by the internal surface roughness of the microstructures. This in turn is determined by the geometries of the microstructures as well as gravity-assisted reactions. In conclusion, a monolithic real 3D microstructure has been fabricated by a simple process of direct maskless laser processing capable of customization for various unique requirements in different applications. Several approaches were undertaken in optimizing the fabrication process and maintaining the functionality and structural integrity of the device. This enables the successful demonstration of the mixing capability of the micro-mixer. Detailed mechanism is also carefully investigated in this thesis. vii List of Figures  LIST OF FIGURES Fig. 2.1. Structure of the monolithic 2-level 3D micro-mixer: (a) micro-mixer fabricated inside FoturanTM glass by femtosecond laser, (b) micro-mixer after thermal annealing cycle and (c) 3D micro-mixer after the final etching process. 37 Fig. 3.1. Experimental setup for the femtosecond laser irradiation of FoturanTM glass. 46 Fig. 3.2. (a) Setup of the irradiation process, comprising of the femtosecond laser together with the optical setup as well as the axes stage. Red arrows depict the path of the laser. (b) and (c) Closed up views of the magnifying lens and axes stage. 47 Fig. 3.3. Design of the microsctructure within the FoturanTM samples from different viewing angles; (a) Top view. (b) Isometric view. (a) Front view. (b) Side view. 49 Figure 3.4. HP4284A Precision LCR Meter Dielectric Tester oven employed in the 2-stage annealing process. 50 Figure 3.5. Olympus MX-50 optical microscope with magnification lens of 10, 20, 50, 80, 100 and 150. 52 Figure 3.6. Magnification module of the Olympus MX-50 optical microscope. 53 Figure 3.7. JEOL JSM 7401F. 54 Figure 3.8. Mitutoyo Surftest Extreme SV-3000CNC 3D surface profiler. 56 Fig. 3.10. (a) Structure of the fabricated monolithic 2-level 3D micro-mixer. (b) Mixing of the yellow and blue dyes in the central micro-reservoir resulting in a green dye solution. (c) Mixing of the yellow and pink dyes. 59 viii References for Chapter 1 Introduction  [12] M.A. Burns, B.N. Johnson, S.N. Brahmasandra, K. Handique, J.R. Webster, M. Krishnan, T.S. Sammarco, P.M. Man, D. Jones, D. Heldsinger, C.H. Mastrangelo, D.T. Burke, Science 282, 484 (1998) [13] V. Lien, K. Zhao, Y. Lo, Appl. Phys. Lett. 87, 194 106 (2005) [14] S. Balslev, A. Kristensen, Opt. Express 13, 344 (2005) [15] Y. Cheng, K. Sugioka, K. Midorikawa, Opt Express 13, 7225 (2005) [16] K.W. Ho, K. Lim, B.C. Shim, J.H. Hahn, Anal. Chem. 77, 5160 (2005) [17] A.A. Said, M. Dugan, P. Bado, Y. Bellouard, A. Scott, J.R. Mabesa Jr., Proc. SPIE 5339, 194 (2004) [18] Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, K. Shihoyama, Opt. Lett. 28, 1144 (2003) [19] Y. Cheng, H. Tsai, K. Sugioka, K. Midorikawa, Appl. Phys. A 85, 11 (2006) [20] T.R. Dietrich, W. Ehrfeld, M. Lacher, M. Kramer, B. Speit: Microelec. Eng. 30, 497 (1996) [21] K. Sugioka, M. Masuda, T. Hongo, Y. Cheng, K. Shihoyama, K. Midorikawa: Appl. Phys. A 79, 815 (2004) [22] Y. Cheng, K. Sugioka, M. Masuda, K. Shihoyama, K. Toyoda, K. Midorikawa: SPIE Proc. 5063, 103 (2003) [23] M. Masuda, K. Sugioka, Y. Cheng, T. Hongo, K. Shihoyama, H. Takai, I. Miyamoto, K. Midorikawa: Appl. Phys. A 78, 1029 (2004) [24] F.E. Livingston, H. Helvajian: U.S. Patent No. 6,783,920, issued Aug. 31, 2004 [25] S.D. Stookey, Ind. Eng. Chem. 51 (1959) 805. References for Chapter 1 Introduction  [26] M. Masuda, K. Sugioka, Y. Cheng, N. Aoki, M. Kawachi, K. Shihoyama, K. Toyoda, H. Helvajian, and K. Midorikawa, Appl. Phys. A: Mater. Sci. Process. 76, 857 (2003). [27] M. Abraham, I. Gomez-Morilla, M. Marsh, and G. Grime, Mater. Res. Soc. Symp. Proc. 739, H2.8.1 (2003). [28] A. C. Fisher, K. A. Gooch, I. E. Henley, and K. Yunus, Anal. Sci. 17, i371 (2001). [29] V. R. Bhardwaj, E. Simova, P. B. Corkum, D. M. Rayner, C. Hnatovsky, R. S. Taylor, B. Schreder, M. Kluge, and J. Zimmer, J. Appl. Phys. 97, 083102 (2005). [30] Y. Cheng, K. Sugioka, M. Masuda, K. Shihoyama, K. Toyoda, and K. Midorikawa, Opt. Express 11, 1809 (2003). [31] K. M. Davis, K. Miura, N. Sugimoto, and K. Hirao, Opt. Lett. 21, 1729 (1996). [32] C.J. Morgan, R.R. Vallance, E.R. Marsh: J. Micromech. Microeng. 14, 1687 (2004) [33] K.W. Kirby, A.T. Jankiewicz: J. Laser Appl. 10, (1998) [34] Gre´ tillat MA, Paoletti F, Thie´baud P, Roth S, Koudelka-Hep M, de Rooij NF (1997) A new fabrication method for borosilicate glass capillary tubes with lateral insets and outlets. Sens Actuators A 60:219–222 [35] Li X, Abe T, Esashi M (2001) Deep reactive ion etching of pyrex glass using SF6 plasma. Sens Actuators A 87:139–145 [36] Nikumb S, Chen Q, Li C, Reshef H, Zheng HY, Qiu H, Low D (2005) Precision glass machining, drilling and profile cutting by short pulse laser. Thin Solid Films 477:216–221 References for Chapter 1 Introduction  [37] Morgan CJ, Wallance RR, Marsh ER (2004) Micro machining glass with polycrystalline diamond tools shaped by micro electro discharge machining. J Micromech Microeng 14:1687–1692 [38] Plaza JA, Lopez MJ, Moreno A, Duch M, Cane C (2003) Definition of high aspect ratio columns. J Sens Actuators A 105:305–310 [39] Yan BH, Wang AC, Huang CY, Huang FY (2002) Study of precision micro-holes in borosilicate glass using micro EDM combined with micro ultrasonic vibration machining. Int J Mach Tools Manuf 42:1105–1112 [40] Merz P, Quenzer HQ, Bernt H, Wagner B, Zoberbier M (2003) A novel micromachining technology for structuring borosilicate glass substrates. In: IEEE proceedings of the 12th international conference on solid state sensors, actuators and microsystems, Boston, June 2003, pp 258–261 [41] Gimkiewicz C, Gerhard E (1997) High-aspect micro-wing wheels in photosensitive glass. Microsyst Technol 4:40–45 [42] Masuda M, Sugioka K, Cheng Y, Aoki N, Kawachi M, Shihoyama K, Toyoda K, Helvajian H, Midorikawa K (2003) 3D microstructuring inside photosensitive glass by femtosecond laser excitation. Appl Phys A 76:857–860 [43] S.D. Stookey: Indust. Eng. Chem. 41, 856 (1949) [44] W.W. Hansen, S.W. Janson, H. Helvajian: SPIE Proc. 2991, 104 (1997) [45] P.D. Fuqua, D.P. Taylor, H. Helvajian, W.W. Hansen, M.H. Abraham: Mat. Res. Soc. Symp. Proc. 624, 79 (2000) [46] S.W. Janson, A. Huang, W.W. Hansen, H. Helvajian: AIAA paper 2004- 6701, Conference on Micro-Nano-Technologies, Monterey, CA, 2004 References for Chapter 1 Introduction  [47] F.E. Livingston, P.M. Adams, H. Helvajian: (2005), submitted to J. Appl. Phys. [48] F.E. Livingston, P.M. Adams, H. Helvajian: SPIE Proc. Laser Prec. Microfabr. 5662, 44 (2004) [49] F.E. Livingston, H. Helvajian: Photophysical Processes that Lead to AblationFree Microfabrication in Glass-Ceramic Materials. In: 3D Laser Microfabrication; H. Misawa, S. Juodkazis (Eds.) (Wiley-VCH Verlag GmbH & Co.: Weinheim, Germany 2005), in press References for Chapter 2 Theoretical Background  References: [1] H.Misawa: Three-Dimensional Optical Memory Element and Method of Writing Information, Jpn. patent app. 023 614 (1995), acceptance No. 961 126, [2] H. Sun, Y. Xu, S. Juodkazis, K. Sun, M. Watanabe, S. Matsuo, H. Misawa, J. Nishii: Opt. Lett. 26(6), 325 (2001) [3] K. Yamasaki, S. Juodkazis, S. Matsuo, H. Misawa: Appl. Phys. A 77, 371 (2003) [4] M. Watanabe, Thesis of Mech. Eng., Tokushima Univ., Japan (BSc. 1996, MSc. 1998) [5] Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, K. Shihoyama: Opt. Lett. 28, 55 (2003) [6] K. M. Davis, K. Miura, N. Sugimoto, and K. Hirao, “Writing waveguides in glass with a femtosecond laser,” Opt. Lett. 21, 1729-1731 (1996). [7] Y. Li, W. Watanabe, K. Yamada, T. Shinagawa, K. Itoh, J. Nishii, and Y. Jiang, “Holographic fabrication of multiple layers of grating inside soda-lime glass with femtosecond laser pulses,” Appl. Phys. Lett. 80, 1508-1510 (2002). [8] J. W. Chan, T. R. Huser, S. H. Risbud, J. S. Hayden, and D. M. Krol, “Waveguide fabrication in phosphate glasses using femtosecond laser pulses,” Appl. Phys. Lett. 82, 2371-2373 (2003). [9] 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, 1516-1518 (2001). References for Chapter 2 Theoretical Background  [10] S.H.Cho, H. Kumagai, and K. Midorikawa, “Fabrication of internal diffraction gratings in planar silica plates using low-density plasma formation induced by a femtosecond laser,” Nucl. Instrum. Methods Phys. Res. B 197, 73-82 (2002). [11] E. G. Gamaly, A. V. Rode, B. Luther-Davies, and V. T. Tikhonchuk, Phys. Plasmas 9, 949 _2002_. [12] D. Du, X. Liu, G. Korn, J. Squier, and G. Mourou, Appl. Phys. Lett. 64, 3071 (1994). [13] D. Ashkenasi, H. Varel, A. Rosenfeld, S. Henz, J. Hermann, and E. E. B. Campbell, Appl. Phys. Lett. 72, 1442 (1998). [14] D. Bäuerle, Laser Processing and Chemistry, 3rd ed. (Springer, Berlin, 2000), p. 788. [15] H. Nakano, T. Nishikawa, and N. Uesugi, Appl. Phys. Lett. 70, 16 (1997). [16] S. D. Stookey, J. Phot. Soc. Am. 14, 399 (1948). [17] S. K. Ahn, J. G. Kim, V. Perez-Mendez, S. Chang, K. H. Jackson, J. A. Kadyk, W. A. Wenzel, and G. Cho, IEEE Trans. Nucl. Sci. 49, 870 (2002). [18] K. Yunus, C. B. Marks, A. C. Fisher, D. W. E. Allsopp, T. J. Ryan, R. A. W. Dryfe, S. S. Hill, E. P. L. Roberts, and C. M. Brennan, Electrochem. Commun. 4, 579 (2002). [19] Q. H. Wang, A. A. Setlur, J. M. Lauerhass, J. Y. Dai, E. W. Seelig, and R. P. H. Chang, Appl. Phys. Lett. 72, 579 (1998). [20] A. Ruf, J. Diebel, M. Abraham, T. R. Dietrich, and M. Lacher, J. Micromech. Microeng. 6, 254 (1996). References for Chapter 2 Theoretical Background  [21] H. Helvajian, P. D. Fuqua, W. W. Hansen, and S. Janson, Proc. SPIE 4088, 319 (2000). [22] P.J. Brock, M.D. Levenson, J.M. Zavislan, J.R. Lyerla, J. Vac. Sci. Technol. B 9, 3155 (1991) [23] J. Kim, H. Berberoglu, X. Xu, J. Microlith. Microfab. Microsyst. 3, 478 (2004) [24] Y. Kondo, J. Qiu, T. Mitsuyu, K. Hirao, and T. Yoko, Jpn. J. Appl. Phys., Part 38, L1146 (1999). [25] M. Masuda, K. Sugioka, Y. Cheng, N. Aoki, M. Kawachi, K. Shihoyama, K. Toyoda, H. Helvajian, and K. Midorikawa, Appl. Phys. A: Mater. Sci. Process. 76, 857 (2003). [26] H. Helvajian, P.D. Fuqua, W.W. Hansen, S. Janson, RIKEN Rev. 32, 57 (2001) [27] V. Arbuzov, J. Non-Cryst. Solids 253, 37 (1999) [28] W.W. Hansen, S.J. Janson, H. Helvajian, Proc. SPIE 2991 (1997) 104; P.D. Fuqua, S.W. Janson, W.W. Hansen, H. Helvajian, Proc. SPIE 3618 (1999) 213. [29] Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, K. Shihoyama, Opt. Lett. 28 (2003) 1144. [30] P. D. Fuqua, D. P. Taylor, H. Helvajian, W. W. Hansen, and M. H. Abraham, Mater. Res. Soc. Symp. Proc. 624, 79 (2000). [31] H. Helvajian, Direct-Write Technologies for Rapid Prototyping Applications, Academic Press, NY, 2002, p. 415; [32] Y. Cheng, K. Sugioka, M. Masuda, K. Midorikawa, M. Kawachi, K. Shihoyama, K. Toyoda, Proc. SPIE 4977 (2003) 314. References for Chapter 2 Theoretical Background  [33] P. Hing, P.W. McMillan, J. Mater. Sci. (1973) 1041; M.P. Borom, A.M. Tukalo, R.H. Doremus, J. Am. Ceram. Soc. 58 (1975) 385. [34] A. Huang, W.W. Hansen, S.W. Janson, H. Helvajian, Proc. SPIE 4559 (2001) 164; A. Huang, W.W. Hansen, S.W. Janson, H. Helvajian, Proc. SPIE 4637 (2002) 297. [35] S.D. Stookey, Indust. Engin. Chem. 41, 856 (1949) [36] F. E. Livingston, P. M. Adams and H. Helvajian, Appl. Phys. A 89, 97-107 (2007). [37] Ya Cheng, Koji Sugioka and Katsumi Midorikawa, Applied Surface Science 248, 172-176 (2005). [38] Ya Cheng, Koji Sugioka, Masashi Masuda, Kazuhiko Shihoyama, Koichi Toyoda and Katsumi Midorikawa, Optics Express 11(15), 1809-1816 (2003). [39] S.D. Stookey, Indust. Engin. Chem. 45, 115 (1953) [40] A. Berezhnoi, Glass-Ceramics and Photo-Sitalls (Plenum Press, New York, 1970) [41] N. Garcia, E. V. Ponizovskaya, and J. Q. Xiao, “Zero permittivity materials: Band gaps at the visible,” Appl. Phys. Lett. 80, 1120-1122 (2002). [42] F.E. Livingston, H. Helvajian, Proc. SPIE 4830, 189 (2003) [43] F.E. Livingston, H. Helvajian, Appl. Phys. A 81, 1569 (2005) References for Chapter 3 Experimental Setup  References: [1] Chantal Khan Malek, Laurent Robert, Jean-Jacques Boy and Pascal Blind, Microsyst. Technol 13, 447-453 (2007). [2] A. A. Bettiol, C. N. B. Udalagama, E. J. Teo, J. A. van Kan and F. Watt, Nuclear Instruments and Methods in Physics Research B 260, 357-361 (2007). [3] F. E. Livingston, P. M. Adams and H. Helvajian, Appl. Phys. A 89, 97-107 (2007). [4] Y. Cheng, H. L. Tsai, K. Sugioka and K. Midorikawa, Appl. Phys. A 85, 11-14 (2006). [5] A. A. Bettiol, S. Venugopal rao, E. J. Teo, J. A. van Kan and Frank Watt, Applied Physics Letters 88, 171106 (2006). [6] A. A. Bettiol, S. Venugopal rao, T. C. Sum, J. A. van Kan and F. Watt, Journal of Crystal Growth 288, 209-212 (2006). [7] S. Juodkazis, K. Yamasaki, V. Mizeikis, S. Matsuo and H. Misawa, Appl. Phys. A 79, 1549-1553 (2004). [8] F. E. Livingston, P. M. Adams and H. Helvajian, Applied Surface Science 247, 526-536 (2005). [9] Ya Cheng, Koji Sugioka and Katsumi Midorikawa, Applied Surface Science 248, 172-176 (2005).  [10] Ya Cheng, Koji Sugioka, Masashi Masuda, Kazuhiko Shihoyama, Koichi Toyoda and Katsumi Midorikawa, Optics Express 11(15), 1809-1816 (2003). [11] R. An, Y. Li, D. Liu, Y. Dou, F. Qi, H. Yang and Q. Gong, Appl. Phys. A 86, 343-346 (2007). 10 References for Chapter 3 Experimental Setup  [12] B. Fisette, F. Busque, J. –Y. Degorce and M. Meunier, Applied Physics Letters 88, 091104 (2006). [13] Zhongke Wang, Koji Sugioka and Katsumi Midorikawa, Appl. Phys. A 89, 951955 (2007). [14] F. E. Livingston and H. Helvajian, Appl. Phys. A 81, 1569-1581 (2005). [15] V. R. Bhardwaj, E. Simova, P. B. Corkum, D. M. Rayner, C. Hnatovsky, R. S. Taylor, B. Schreder, M. Kluge and J. Zimmer, Journal of Applied Physics 97, 083102 (2005). [16] Young-Rae Choo, Jae-Yeol Oh, Heui-Soo Kim, Hyo-Soo Jeong, Materials Science and Engineering B64, 79-83, (1999) [17] T. R. Dietrich, W. Ehrfeld. M. Lacher, M. Krämer and B. Speit, Microelectronic Engineering 30, 497-504 (1996). 11 References for Chapter 4 3‐Dimensional Microstructural  Fabrication by Femtosecond Laser Microprocessing  References: [1] Chantal Khan Malek, Laurent Robert, Jean-Jacques Boy and Pascal Blind, Microsyst. Technol 13, 447-453 (2007). [2] Ya Cheng, Koji Sugioka and Katsumi Midorikawa, Applied Surface Science 248, 172-176 (2005). [3] A. A. Bettiol, C. N. B. Udalagama, E. J. Teo, J. A. van Kan and F. Watt, Nuclear Instruments and Methods in Physics Research B 260, 357-361 (2007). [4] Y. Cheng, H. L. Tsai, K. Sugioka and K. Midorikawa, Appl. Phys. A 85, 11-14 (2006). [5] A. A. Bettiol, S. Venugopal rao, E. J. Teo, J. A. van Kan and Frank Watt, Applied Physics Letters 88, 171106 (2006). [6] A. A. Bettiol, S. Venugopal rao, T. C. Sum, J. A. van Kan and F. Watt, Journal of Crystal Growth 288, 209-212 (2006). [7] S. Juodkazis, K. Yamasaki, V. Mizeikis, S. Matsuo and H. Misawa, Appl. Phys. A 79, 1549-1553 (2004). [8] R. An, Y. Li, D. Liu, Y. Dou, F. Qi, H. Yang and Q. Gong, Appl. Phys. A 86, 343-346 (2007). [9] B. Fisette, F. Busque, J. –Y. Degorce and M. Meunier, Applied Physics Letters 88, 091104 (2006). [10] F. E. Livingston and H. Helvajian, Appl. Phys. A 81, 1569-1581 (2005). [11] Multi-Photon Absorption and Ionization , Department of Physics, Davidson College 12 References for Chapter 4 3‐Dimensional Microstructural  Fabrication by Femtosecond Laser Microprocessing  [12] F. E. Livingston, P. M. Adams and H. Helvajian, Applied Surface Science 247, 526-536 (2005). 13 References for Chapter 5 Results and Discussion  References: [1] P.S. Dittrich, K. Tachikawa, A. Manz, Anal. Chem. 78, 3887 (2006) [2] M. Bua, T. Melvin, G.J. Ensell, J.S. Wilkinson, A.G.R. Evans, Sen. Actuators A 115, 476 (2004) [3] Y. Shimotsuma, K. Hirao, P.G. Kazansky, J. Qiu, Jan. J. Appl. Phys. 44, 4735 (2005) [4] R.T. Kelly, A.T. Woolley, Anal. Chem. A-Page Mar. 1, 97A–102A (2005) [5] B. Fisette, M. Meunier, J. Laser Micro/Nanoeng. 1, (2006) [6] Y. Bellouard, A.A. Said, P. Bado, Opt. Express. 13, 6635 (2005) [7] H.Misawa: Three-Dimensional Optical Memory Element and Method of Writing Information, Jpn. patent app. 023 614 (1995), acceptance No. 961 126, [8] K.M. Davis, K. Miura, N. Sugimoto, K. Hirao: Opt. Lett. 21, 1729 (1996) [9] M. Watanabe, H.B. Sun, S. Juodkazis, T. Takahashi, S. Matsuo, Y. Suzuki, J. Nishii, H. Misawa: Jpn. J. Appl. Phys. 27(12B), L1527 (1998) [10] K. Yamasaki, S. Juodkazis, M. Watanabe, H.-B. Sun, S. Matsuo, H. Misawa: Appl. Phys. Lett. 76(8), 1000 (2000) [11] H. Sun, Y. Xu, S. Juodkazis, K. Sun, M. Watanabe, S. Matsuo, H. Misawa, J. Nishii: Opt. Lett. 26(6), 325 (2001) [12] K. Yamasaki, S. Juodkazis, S. Matsuo, H. Misawa: Appl. Phys. A 77, 371 (2003) [13] M. Watanabe, Thesis of Mech. Eng., Tokushima Univ., Japan (BSc. 1996, MSc. 1998) 14 References for Chapter 5 Results and Discussion  [14] A. Marcinkevicius, S. Juodkazis, M. Watanabe, M. Miwa, S. Matsuo, H. Misawa, J. Nishii: Opt. Lett. 26(5), 277 (2001) [15] Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, K. Shihoyama: Opt. Lett. 28, 55 (2003) [16] Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, K. Shihoyama: Opt. Lett. 28(13), 1144 (2003) [17] K. Kajihara, L. Skuja, M. Hirano, H. Hosono, Appl. Phys. Lett. 79 (2001) 1757. [18] P. Hing, P.W. McMillan, J. Mater. Sci. (1973) 1041; [19] M. Masuda, K. Sugioka, Y. Cheng, N. Aoki, M. Kawachi, K. Shihoyama, K. Toyoda, H. Helvajian, K. Midorikawa, Appl. Phys. A 76, 857 (2003) [20] H. Helvajian, P.D. Fuqua, W.W. Hansen, S. Janson, RIKEN Rev. 32, 57 (2001) [21] Y. Kondo, J. Qiu, T. Mitsuyu, K. Hirao, T. Yoko, Japan J. Appl. Phys. 38, L1146 (1999) [22] http://www.mikroglas.com/foturane.htm (C) 2003 OSA 28 July 2003 / Vol. 11, No. 15 / OPTICS EXPRESS 1809 #2547 - $15.00 US Received June 02, 2003; Revised July 23, 2003 [23] T. Hongo, K. Sugioka, H. Niino, Y. Cheng, M. Masuda, J. Miyamoto, H. Takai, K. Midorikawa, J. Appl. Phys. 97, 063 517 (2005) [24] V.R. Bhardwaj, E. Simova, P.B. Corkum, D.M. Rayner, C. Hnatovsky, R.S. Taylor, B. Schreder, M. Kluge, J. Zimmer, J. Appl. Phys. 97, 083 102 (2005) [25] D. Homoelle, S. Wielandy, A. L. Gaeta, N. F. Borrelli, and Charlene Smith, “Infrared photosensitivity in silica glasses exposed to femtosecond laser pulses,” Opt. Lett. 24, 1311-1313 (1999). 15 References for Chapter 5 Results and Discussion  [26] Y. Li, W. Watanabe, K. Yamada, T. Shinagawa, K. Itoh, J. Nishii, and Y. Jiang, “Holographic fabrication of multiple layers of grating inside soda-lime glass with femtosecond laser pulses,” Appl. Phys. Lett. 80, 1508-1510 (2002). [27] J. W. Chan, T. R. Huser, S. H. Risbud, J. S. Hayden, and D. M. Krol, “Waveguide fabrication in phosphate glasses using femtosecond laser pulses,” Appl. Phys. Lett. 82, 2371-2373 (2003). [28] 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, 1516-1518 (2001). [29] S.H.Cho, H. Kumagai, and K. Midorikawa, “Fabrication of internal diffraction gratings in planar silica plates using low-density plasma formation induced by a femtosecond laser,” Nucl. Instrum. Methods Phys. Res. B 197, 73-82 (2002). [30] E. N. Glezer and E. Mazur, “Ultrafast-laser driven micro-explosions in transparent materials,” Appl. Phys. Lett. 71, 882-884 (1997). [31] F.E. Livingston, H. Helvajian, Photophysical Processes that Lead to AblationFree Microfabrication, in: Glass-Ceramic Materials, in: 3D Laser Microfabrication, ed. by H. Misawa, S. Juodkazis (Wiley-VCH, Weinheim, 2006) and references therein [32] S.D. Stookey, Ind. Eng. Chem. 41 (1949) 856. [33] Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, and K. Shihoyama, “Control of the cross-sectional shape of a hollow microchannel embedded in photostructurable glass by use of a femtosecond laser,” Opt. Lett. 28, 55-57 (2003). 16 References for Chapter 5 Results and Discussion  [34] Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, and K. Shihoyama, “Three dimensional microoptical components embedded in photosensitive glass by a femtosecond laser,” Opt. Lett. 28, 1144-1146 (2003). [35] N. Garcia, E. V. Ponizovskaya, and J. Q. Xiao, “Zero permittivity materials: Band gaps at the visible,” Appl. Phys. Lett. 80, 1120-1122 (2002). [36] R. F. Madrigal, L. C. S. Blaya, M. Ulibarrena, A. Belendez, and A. Fimia, “Diffraction efficiency of unbleached phase and amplitude holograms as a function of volume fraction of metallic silver,” Opt. Commun. 201, 279-282 (2002). [37] P.D. Fuqua, D.P. Taylor, H. Helvajian, W.W. Hansen, M.H. Abraham, Mater. Res. Soc. Proc. 624 (2000) 79. [38] H. Helvajian, Direct-Write Technologies for Rapid Prototyping Applications, Academic Press, NY, 2002, p. 415; Y. Cheng, K. Sugioka, M. Masuda, K. Midorikawa, M. Kawachi, K. Shihoyama, K. Toyoda, Proc. SPIE 4977 (2003) 314; J. Kim, H. Berberoglu, X. Xu, Proc. SPIE 4977 (2003) 324. [39] Y. Cheng, K. Sugioka, M. Masuda, K. Midorikawa, M. Kawachi, K. Shihoyama, K. Toyoda, Proc. SPIE 4977 (2003) 314. [40] W.W. Hansen, S.J. Janson, H. Helvajian, Proc. SPIE (1997) 104; Y. Cheng, K. Sugioka, K. Midorikawa, M. Masuda, K. Toyoda, M. Kawachi, K. Shihoyama, Opt. Lett. 28 (2003) 1144. 17 [...]... fabrication of micro-optical components, such as waveguides [29], gratings [30 ], and micro-mirrors [26] Although femtosecond lasers are commonly used for waveguide fabrication in many types of glasses [31 ], only a limited number of studies have been concentrated on the fabrication of multi-level 3D microstructures within FoturanTM 8 Chapter 1 Introduction  1 .3 Limitations of Conventional Glass and Challenges... Glaswerke, with their know-how in the fields of glass and glass ceramics together with the IMM Institute of Microtechnology GmbH (Mainz), with its technical facilities and knowledge in the field of microtechnology, are working together on the field of photo-structurable glass The trade name of this glass, made by Schott, is FoturanTM All results mentioned here are made with this glass Similar glasses... a monolithic 2-level 3 dimensional (3D) multi-channel structures in-situ of FoturanTM glass Design fabrication has been proposed and demonstrated The mechanism of the process behind the fabrication of these structures is also discussed in the following chapters 1.5.1 Fabrication of a Monolithic 2-level 3- dimensional Micro-mixer Currently, the main fabrication method makes use of lithography technology... s2) x List of Publications  LIST OF PUBLICATIONS 1 H H Teo and M H Hong, A Monolithic 2-level 3- Dimensional Micro-mixer Fabrication by Femtosecond Laser and its Characterization, 5th International Congress on Laser Advanced Materials Processing 2 H H Teo, M H Hong, L.P Shi and T.C Chong, Optical Diagnostics of Femtosecond Laser Processing of Foturan Glass, 10th International Conference on Laser Ablation... of femtosecond laser irradiation with the principle of non-linear multi-photons absorption This permits the fabrication of embedded intricate 3D structures within the material and the ability to create undercut and free-standing structures without resorting to ablation, thereby, minimizing undue residual stress created as well as impending issues of surface morphology Conventional processing of glass. .. Chapter 1 Introduction  Fabrication of precise microstructures in a controlled fashion made out of glass, in particular in glass for micro-fluidics [7] is very challenging The difficulty of fabricating structures in glass is evident in the wide variety of non-conventional techniques for glass micromachining along with some conventional micro -fabrication technologies Glass micro -fabrication technologies... varying depths inside the FoturanTM samples This direct laser writing within FoturanTM makes use of the multi-photon absorption principle of the femtosecond laser Only at the focused point will there be a structural change, this enables microstructures to be fabricated within the sample, regardless of their shapes and sizes The main setup involves only a femtosecond laser source and a 3 axes stage, which... structures, for example, micro-reactors for chemical analyses [10] and a number of micro-optical structures, such as micro-fluidic dye laser [11] in a photosensitive FoturanTM glass chip by femtosecond (fs) laser microprocessing The ability to directly fabricate 3D microstructures in FoturanTM glass by using the femtosecond laser, along with its resistance to high temperature and corrosion as well as high optical... enhance the efficiencies of inducing and / or collecting signals in optical analyses For this purpose, micro-mirrors have been fabricated inside FoturanTM glass [18] Furthermore, the fabrication of cylindrical and hemispherical microlenses made of FoturanTM glass by fs laser processing has been reported [19] In recent years, we have witnessed a steady progress in the fabrication of micro-fluidic structures,...List of Figures  Fig 4.1 Flow chart of the 2-level 3D micro-mixer fabrication process 63 Fig 4.2 Design of the microstructure within the FoturanTM samples from 4 different viewing angles; (a) Top view (b) Isometric view (a) Front view (b) Side view 65 Fig 4 .3 2-photon absorption of Cesium 68 Fig 4.4 Two-photon Jablonski Energy Diagram 68 Fig 4.5 Temperature-time plot of the annealing cycle . 3.1 Femtosecond Laser Fabrication of Microstructures In-situ of Foturan TM Glass 44 3.1.1 Introduction 44 3.1.2 Experimental Setup of Femtosecond Laser Irradiation of Foturan TM Glass. Experimental setup for the femtosecond laser irradiation of Foturan TM glass. 46 Fig. 3.2. (a) Setup of the irradiation process, comprising of the femtosecond laser together with the optical setup. 3-DIMENSIONAL MICROSTRUCTURAL FABRICATION OF FOTURAN TM GLASS WITH FEMTOSECOND LASER IRRADIATION TEO HONG HAI NATIONAL UNIVERSITY OF SINGAPORE 2009 3-DIMENSTIONAL