The name is absent

42

magnetic parameters: the electric permittivity, c and the magnetic permeability, μ,
as if it is a homogeneous material. In 1999, early research invented metamaterials
based on conducting elements designed to provide a magnetic response at microwave
and lower frequencies [90]. These non-magnetic structures consists of arrays of wire
loops, which have a self-capacitance and self-inductance that create a resonance under
an external magnetic field.

In the literature, metamaterials have demonstrated special electromagnetic behav-
iors such as artifical magnetism and negative refractive index. According to the Snell’s
Law, beams will be deflected on the same side of the normal upon entering a meta-
material with negative refractive index. Such metamaterials designed at microwave
frequencies, composed of negative permittivity and negative permeability, have led
to intense theoretical, computational and experimental studies of exotic phenomena,
such as perfect lensing and cloaking [91-93]. Artifical magnetism at microwave and
THz frequencies has been demonstrated with SRRs [90]. This metamaterial, designed
with a magnetic resonance in the mid-THz region, between 1 and 3 THz, provides a
strong magnetic response not readily available in conventional materials [94]. This
chapter will focus on the use of SRRs in the construction of a THz SLM.

5.2 First-generation 4 × 4 SLM design

The first demonstration of a THz SLM has 4 × 4 pixels, where each pixel is a 4 ×
4 mm² array of metamaterial SRRs, as shown in Figure 5.1(c). The SRR elements
have 200 nm gold thickness, 4 μm line width, 2 μm split gap spacing, 66 μm outer
dimension and 76 μm period such that the device has a resonant transmission at
0.36 THz upon application of a voltage. Each pixel (consisting of approximately
2500 SRRs) is independently controlled by an external voltage across a 1 × 1 mm²

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