In this paper we report on use stack and draw technique to develop volume 2D photonic crystals made of two types of
soft glasses with a large difference of refractive index. Existence of partial photonic bandgap in the material is predicted
and modeled.
The use of nano-structured elements in the fabrication of micro-optical subwavelength components requires a
fully vectorial solution to Maxwell's curl equations. In this paper, we compare the results generated by two
of the main methods used in the solution of the curl equations, the Fourier Modal Method (FMM) and the
Finite Difference Time Domain (FDTD) method. We address the computational issues surrounding the accurate
modelling of nano-structured elements (with features in the 10nm-100nm range) for a range of micro-optical
elements, e.g. cylindrical lenses, photonic bandgap reflectors and polarisation dependent beamsplitters. Finally,
we show the experimental verification of the nano-structured designs using microwave radiation.
Computer generated holograms (CGH) are used to transform an incoming light distribution into a desired output.
Recently multi plane CGHs became of interest since they allow the combination of some well known design methods for
thin CGHs with unique properties of thick holograms. Iterative methods like the iterative Fourier transform algorithm
(IFTA) require an operator that transforms a required optical function into an actual physical structure (e.g. a height
structure). Commonly the thin element approximation (TEA) is used for this purpose. Together with the angular
spectrum of plane waves (APSW) it has also been successfully used in the case of multi plane CGHs. Of course, due to
the approximations inherent in TEA, it can only be applied above a certain feature size. In this contribution we want to
give a first comparison of the TEA & ASPW approach with simulation results from the Fourier modal method (FMM)
for the example of one dimensional, pattern generating, multi plane CGH.
Photonic crystals are wavelength-scale periodic structures built from dielectrics with different refractive indexes As
standard 2D photonic crystals are fabricated by lithographic methods, but in this case only planar structure can be
obtained. We have adapted stack and draw technique that is usually used for photonic crystal fiber fabrication to develop
volume 2D photonic crystals.
Technology allows fabrication of high contrast structures with air holes as well as low contrast solid-all structures where
air holes are replaced with glass micro rods of refractive index. Use of soft glasses with a high difference in refractive
index allows development of a structure where partial photonic band gap exists. The proposed method offers possibility
of fabrication volume 2D photonic crystal with a diameter in the order of 1 mm and height of a few mm. Large area
photonic crystals are very attractive as new optical material named 'photonic glass' with built-in photonic bandgap
functionality. Preliminary fabrication test were performed for two pairs of soft glasses NC21/F2 and SK222/Zr3. The
considered glasses are thermally matched and are synthesized in-house except of F2 glass (standard Schott glass).
Obtained structures are regular with some defects on the borders between intermediate performs. Some glass diffusion is
observed between Zr3 and SK222 glasses. With this technique a 2D photonic crystal with a hexagonal lattice was
fabricated with a pair of soft glasses SK222 and Zr3. Microrod diameter is 749nm and lattice constant 1110 nm.
Photonic crystal consists of 166421 elements (425 elements on diagonal) and its total surface is about field ~0,178mm2.
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