Atsushi Ono , Hiroki Sano , Wataru Inami and Yoshimasa Kawata
Article: Surface Plasmon Excitation and Localization by Metal-Coated Axicon Prism
Micromachines 2012, 3(1), 55-61; doi:10.3390/mi3010055 - published online 8 February 2012
Show/Hide AbstractAbstract: Collimated Gaussian beams are efficiently localized at the apex of a metal-coated axicon prism by surface plasmon excitations. We observed the light scattered at the apex and the light reflected by the prism. Intense scattered light was observed with the radial polarization incidence. Further, each incidence of the radial, azimuthal, and linear polarizations provided field distributions of bright and dark intensities in the reflected images according to the surface plasmon excitation. We have demonstrated that surface plasmon waves are excited at the sides of the prism in the Kretschmann configuration and that they converge to its apex.

Ruoxi Yang , Xiaoyue Huang and Zhaolin Lu
Article: Arbitrary Super Surface Modes Bounded by Multilayered Metametal
Micromachines 2012, 3(1), 45-54; doi:10.3390/mi3010045 - published online 1 February 2012
Show/Hide AbstractAbstract: The dispersion of the fundamental super mode confined along the boundary between a multilayer metal-insulator (MMI) stack and a dielectric coating is theoretically analyzed and compared to the dispersion of surface waves on a single metal-insulator (MI) boundary. Based on the classical Kretschmann setup, the MMI system is experimentally tested as an anisotropic material to exhibit plasmonic behavior and a candidate of “metametal” to engineer the preset surface plasmon frequency of conventional metals for optical sensing applications. The conditions to obtain artificial surface plasmon frequency are thoroughly studied, and the tuning of surface plasmon frequency is verified by electromagnetic modeling and experiments. The design rules drawn in this paper would bring important insights into applications such as optical lithography, nano-sensing and imaging.

Tapas Kumar Saha , Mingyu Lu , Zhenqiang Ma and Weidong Zhou
Article: Design of an Angle Detector for Laser Beams Based on Grating Coupling
Micromachines 2012, 3(1), 36-44; doi:10.3390/mi3010036 - published online 1 February 2012
Show/Hide AbstractAbstract: A novel angle detector for laser beams is designed in this paper. It takes advantage of grating coupling to couple the incident light into a slab waveguide; and, the incident light’s angle can be determined by reading the outputs of light detectors within the waveguide. This device offers fast-responding on-chip detection of laser beam’s angle. Compared to techniques based on quadrant photodiodes or lateral effect photodiodes, the device in this paper has far greater detectable range (up to a few degrees, to be specific). Performance of the laser angle detector in this paper is demonstrated by finite-difference-time-domain simulations. Numerical results show that, the detectable angle range can be adjusted by several design parameters and can reach [−4°, 4°]. The laser beam angle detector in this paper is expected to find various applications such as ultra-fast optical interconnects.

Seonho Seok , Janggil Kim , Nathalie Rolland and Paul-Alain Rolland
Article: A Study on Millimetre-Wave Tunable Bandpass Filter Based on Polymer Cap Deflection
Micromachines 2012, 3(1), 28-35; doi:10.3390/mi3010028 - published online 6 January 2012
Show/Hide AbstractAbstract: This paper presents a new tuning mechanism for millimetre-wave BPF based on deflection of the BCB membrane of BCB packaging cap. A 3-pole parallel-coupled microstrip filter operating at 60 GHz is first implemented on 30 µm-thick BCB polymer substrate and then BCB-capped through our new anti-adhesion layer assisted wafer-level transfer technique. Gold electrodes are fabricated on top of the BCB cap for DC actuation. The implemented BCB capped BPF showed the tuning range of 1.49 GHz from 63.36 GHz to 64.85 GHz with the associated insertion losses of −9.7 dB and −9.4 dB and the return losses better than −11 dB over the tuning range.

Grégory Barbillon
Article: Plasmonic Nanostructures Prepared by Soft UV Nanoimprint Lithography and Their Application in Biological Sensing
Micromachines 2012, 3(1), 21-27; doi:10.3390/mi3010021 - published online 6 January 2012
Show/Hide AbstractAbstract: We prepared high-density plasmonic nanostructures on a glass substrate. By using soft UV nanoimprint lithography, gold nanodisks with a diameter of 65 nm were obtained on an area of 1 mm². We tested these gold nanosensors in the biotin/streptavidin system to study their selectivity and sensitivity of detection. The prepared gold nanodisks could detect streptavidin at 10 pM.

Yanbing Jia , Gilhwan Cha and Yongho Sungtaek Ju
Article: Switchable Thermal Interfaces Based on Discrete Liquid Droplets
Micromachines 2012, 3(1), 10-20; doi:10.3390/mi3010010 - published online 6 January 2012
Show/Hide AbstractAbstract: We present a switchable thermal interface based on an array of discrete liquid droplets initially confined on hydrophilic islands on a substrate. The droplets undergo reversible morphological transition into a continuous liquid film when they are mechanically compressed by an opposing substrate to create low-thermal resistance heat conduction path. We investigate a criterion for reversible switching in terms of hydrophilic pattern size and liquid volume. The dependence of the liquid morphology and rupture distance on the diameter and areal fraction of hydrophilic islands, liquid volumes, as well as loading pressure is also characterized both theoretically and experimentally. The thermal resistance in the on-state is experimentally characterized for ionic liquids, which are promising for practical applications due to their negligible vapor pressure. A life testing setup is constructed to evaluate the reliability of the interface under continued switching conditions at relatively high switching frequencies.