Fabrication of photonic crystal and nonlinear photonic crystal is a key parameter for modern optics with numerous applications in different fields. We propose a powerful fabrication technique based on the interference of two laser beams with multiple exposures. This technique allows to imprint different kinds of periodic and quasi-periodic structures into polymer materials. This fabrication technique allows to realize very structures in a very short fabrication time.

The technique can be applied for different kinds of polymer materials, passive or active. When using a specific quasi-periodic structure, we could directly obtain a polymer-based photonic crystal with a good photonic bandgap as the one obtained with semiconductor material. In particular, when using nonlinear polymer material, we could obtain the so-called nonlinear photonic crystals, which are very interesting for many applications, such as generation of new waves by frequency conversion, high speed optical switching, low threshold laser, etc.

These polymer-based photonic structures could also be transfered to other materials, such as metallic and magnetic materials, which allow to study other physical effects, such as plasmonics and magneto-optics, offering numerous interesting applications.
 

Figure 1 : (a) Optical arrangement of multiple-exposure two-beam interference technique. Two laser beams are of the same profile, polarization, and intensity. These beams interfere in the position of sample that is fixed in a double rotation stage: one can rotate around the z-axis (with an angle) and the other can rotate around the y-axis (with an angle). This technique is useful to fabricate different kinds of periodic (b, c) and quasi-periodic (d, e) micro and nanostructures.

References:

1. Tamara Pogosian and Ngoc Diep Lai, Theoretical investigation of three-dimensional quasi-phase-matching photonic structures, Phys. Rev. A 94, 063821 (2016).
   
2. Minh Thanh Do, Quang Cong Tong, Mai Hoang Luong, Alexander Lidiak, Isabelle Ledoux-Rak, and Ngoc Diep Lai, Fabrication and Characterization of Large-Area Unpatterned and Patterned Plasmonic Gold Nanostructures, Journal of Electronic Materials 45, 2347-2353 (2016).
3.  Minh Thanh Do, Quang Cong Tong, Alexander Lidiak, Mai Hoang Luong, Isabelle Ledoux-Rak, and Ngoc Diep Lai, Nano-patterning of gold thin film by thermal annealing combined with laser interference techniques, Appl. Phys. A 122, 360 (2016).
4. Mai Hoang Luong, Thi Thanh Ngan Nguyen, Chi Thanh Nguyen, Isabelle Ledoux-Rak, and Ngoc Diep Lai, Study of all-polymer-based waveguide resonant gratings and their applications for optimization of second-harmonic generation, J. Phys. D: Appl. Phys. 48, 365302 (2015).
5. Thi Thanh Ngan Nguyen, Quang Liem Nguyen, Joseph Zyss, Isabelle Ledoux-Rak, and Ngoc Diep Lai, Optimization of thickness and uniformity of photonic structures fabricated by interference lithography, Appl. Phys. A - Materials Science & Processing 111, 297-302 (2013).
6. X. Wu, T. T. N. Nguyen, I. Ledoux-Rak, C. T. Nguyen, and Ngoc Diep Lai, Optically formation of one- and two-dimensional holographic surface relief grating, Chapter 7, "Holography - Basic principles and Contemporary applications",  INTECH book, 147-170 (2013).
7. Xiao Wu, Thi Thanh Ngan Nguyen, Deyan Sun, Isabelle Ledoux-Rak, Chi Thanh Nguyen, and Ngoc Diep Lai, Incoherent UV/VIS lasers assisted surface relief grating formation, Advanced Materials Research 560-561, 456-461 (2012).
8. Xiao Wu, Thi Thanh Ngan Nguyen, Isabelle Ledoux-Rak, Chi Thanh Nguyen, and Ngoc Diep Lai, UV beam-assisted efficient formation of surface relief grating on azobenzene polymers, Appl. Phys. B - Laser and Optics 107, 819-822 (2012).
9. Ngoc Diep Lai, J. H. Lin, D. B. Do, W. P. Liang, Y. D. Huang, T. S. Zheng, Y. Y. Huang, and C. C. Hsu, Fabrication of two- and three-dimensional photonic crystals and photonic quasi-crystals by interference technique, Book chapter, Holography, Research and Technologies, INTECH, p. 253-278 (2011).
   
10. D. B. Do, J. H. Lin, Ngoc Diep Lai, H. C. Kan, and C. C. Hsu, Fabrication of three-dimensional polymer quadratic nonlinear grating structures by layer-by-layer direct laser writing technique, Appl. Opt. 50, 4664-4670 (2011).
11. D. B. Do, Ngoc Diep Lai, C. Y. Wu, J. H. Lin, and C. C. Hsu, Fabrication of ellipticity-controlled microlens arrays by controlling parameters of multiple-exposure two-beam interference technique, Appl. Opt. 50, 579-585 (2011).
12. Ngoc Diep Lai, T. S. Zheng, D. B. Do, J. H. Lin, and C. C. Hsu, Fabrication of desired three-dimensional structures by holographic assembly technique, Appl. Phys. A 100, 171-175 (2010).
13. C. Y. Wu, T. H. Chiang, Ngoc Diep Lai, D. B. Do, and C. C. Hsu, Fabrication of SU-8 microlens arrays by multi-exposure two-beam interference technique, Appl. Opt. 48, 2473-2479 (2009).
14. Ngoc Diep Lai, Y. D. Huang, D. B. Do, J. H. Lin, and C. C. Hsu, Fabrication of periodic nanovein structures by holography lithography technique, Opt. Express 17, 3362-3369 (2009).