Chair: Annemarie Huijser (Optical Sciences)
This parallel session focuses on advanced periodic nanostructures ranging from photonic crystals to multilayer mirrors and plasmonic antennas. The speakers use advanced optical techniques to characterize these nanostructures, including near-field imaging and pulse shaping.
Short introduction by Annemarie Huijser
Femi Ojambati (COPS)
Optical correlations in 2D and 3D photonic crystals with weak and strong disorder
Dmitry Kuznetsov (XUV)
High reflectance La/B based multilayer mirrors for 6 nm wavelength
Dirk Jan Dikken (OS)
A phased antenna array for surface plasmons
Caterina Taddei (LPNO)
Integrated Microwave Photonics Filters
Optical correlations in 2D and 3D photonic crystals with weak and strong disorder –
Femi Ojambati (Complex Photonic Systems)
Photonic crystals are periodic structures with a periodicity comparable to the wavelength. In an ideal (perfect and infinite) photonic crystal, Bloch modes only propagate. However, a real photonic crystal has structural imperfections in size and position. The imperfections in a real crystal results into scattering, and light transport deviates from that of a perfect crystal. In this presentation, I will present the experimental results of investigating light transport in a real crystal by measuring the reflected intensity from the photonic crystal. We use autocorrelation and cross correlation of the reflected intensity to resolve the periodic structure of the crystal. We qualitatively compare the amount of disorder in one part of the crystal to another part. Furthermore, we will see that there are correlations in the reflected intensity from the crystal.
High reflectance La/B based multilayer mirrors for 6 nm wavelength – Dmitry Kuznetsov (Industrial Focus Group XUV Optics)
For future photolithography processes, the wavelength of 6 nm is candidate for high resolution imaging. The perspective of this chip fabrication technique however, will depend essentially on the performance of multilayer reflective mirrors, which will need to be based on La/B multilayer reflectors. One of the issues is the formation of LaxBy compounds at the interfaces, which decreases the optical contrast and therefore reduces the reflectivity. To prevent such chemical interaction, passivation of the La layers by nitrogen has been investigated. We successfully synthesized LaN layers that resulted in a new world record reflectivity of 64.1% at ~6.7 nm at near normal incidence. This significantly reduces the gap to the target of 70% reflectivity, desired for a possible next generation of lithography.
A phased antenna array for surface plasmons – Dirk Jan Dikken (Optical Sciences)
Surface plasmon polaritons are electromagnetic waves that propagate tightly bound to metal surfaces. The concentration of the electromagnetic field at the surface as well as the short wavelength of surface plasmons enable sensitive detection methods and miniaturization of optics. We present an antenna array for plasmons in which the phase of each antenna element is fully and independently controlled. Individual holes in a thick gold film act as dipolar emitters of surface plasmon polaritons whose phase is controlled individually using a digital spatial light modulator. We experimentally show, using a phase sensitive near-field microscope, that this allows accurate directional emission of surface waves. Our method presents a compact and flexible way to dynamically shape the propagation of plasmons and holds promise for nanophotonic applications employing propagating surface plasmons.
Integrated Microwave Photonics Filters – Caterina Taddei (Laser Physics and Nonlinear Optics)
Microwave Photonics (MWP) is a promising field aiming at optical processing of electronic (GHz) data, such as complex filtering, beyond what is possible with conventional, all-electronic methods. Despite the increasing interest in MWP, current approaches based on standard technology such as fibers are limited by high instability and bulkiness. Here we focus on Integrated MWP filters fabricated using low-loss, high-index contrast Si3N4/SiO2 waveguide technology. As typical examples we present temporal differentiation, channel selection in satellite communication systems and true time delay beamsteering of antenna arrays.