Journal of the Optical Society of Korea
Vol. 19, No. 1, February 2015, pp. 63-68
- 63 -
Fabrication of Large Area Photonic Crystals with Periodic Defects by
One-Step Holographic Lithography
Jie Ma
2
, Kam Sing Wong
1
, Shan Li
2
, Zhe Chen
2
, Jianying Zhou
3
, and Yongchun Zhong
1,2
*
1
Department of Physics, Hong Kong University of Science & Technology,
Hong Kong 999077, P. R. China
2
Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher
Education Institutes, Jinan University, Guangzhou 510632, P. R. China
3
State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University,
Guangzhou 510275, P. R. China
(Received September 29, 2014 : revised December 23, 2014 : accepted January 6, 2015)
A one-step fabrication of a photonic crystal (PC) with functional defects is demonstrated. Using multi-beam
phase-controlled holographic lithography with a diffracting optical element, large area one dimensional (1D)
and two dimensional (2D) PCs with periodic defects were fabricated. The uniform area is up to 2 mm
2
,
and tens of defect channels have been introduced in the 1D and 2D PC structure. This technique gives
rise to substantial reduction in the fabrication complexity and significant improvement in the spatial
accuracy of introducing functional defects in photonic crystals. This method can also be used to design
and fabricate three dimensional (3D) PCs with periodic defects.
Keywords : Defects, Photonic crystals, Holographic lithography, Liquid crystal-spatial light modulators
OCIS codes : (160.5298) Photonic crystals; (130.5296) Photonic crystal waveguides; (220.3740)
Lithography; (070.6120) Spatial light modulators
*Corresponding author: ychzhong@163.com
Color versions of one or more of the figures in this paper are available online.
I. INTRODUCTION
Photonic crystals (PCs), proposed in 1987 [1, 2], have
undergone rapid development in recent years. Fabrication
of 3D PCs was a great challenge over the past decades.
Several techniques have succeeded to a certain degree in
fabricating 3D PCs. These techniques include e-beam lithography
for multilayer stacking of woodpile structures [3], colloidal
self-assembly [4], multi-photon direct laser writing [5], and
holographic lithography (HL) based on multiple beam inter-
ference [6-8]. Using HL to make PCs is one of the most
promising techniques for mass production of large area,
defect free PC structures. The pattern can be controlled by
the beam propagation direction, the number of the interfering
beams, the beam intensities, their respective polarizations
and relative phases [9]. So far holographic lithography has
been successful in fabricating large area, high quality PCs
templates [6, 7]. Since the applications of PCs usually
require accurate introduction of defects into the PCs’ structure,
developing a method to effectively and accurately incorporate
functional defects directly into PCs is necessary [10-12].
One way is directly writing by femtosecond laser after the
crystal has already been formed [10]. However, this technique
requires a costly and complicated second step and an
accuracy aligning to the manufacturing process [10]. In 2004,
the phase-control holographic lithography was used to
introduce defects in a single step [13]. This technique is
based on multi-beam diffraction with a phase mask, whose
pixels should be much smaller than the period of the PCs,
and thousands of pixels are required. Since the smallest
pixel of the controlled phase mask is about 1 μm, the period
of the fabricated PCs is larger than a few μm by using this
technique. Recently, we developed a novel method to introduce
defects into the PCs using one-step holographic lithography
[14]. A liquid crystal spatial light modulator (LC-SLM) was
used to control the phases of interference beamlets. This
technique is based on multi-beam interference, the pixel of
SLM can be very large (up to 1~2 mm), and ten pixels are
enough to fabricate a photonic crystal structure with defects.
However, as a lens had been used to focus the interference
ISSN: 1226-4776(Print) / ISSN: 2093-6885(Online)
DOI:
http://dx.doi.org/10.3807/JOSK.2015.19.1.063