The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Self-assembly is a process in which components, either separate or linked, spontaneously form ordered aggregates. Self-assembly can occur with components having sizes from the molecular to the macroscopic, provided that appropriate conditions are met. Although much of the work in self-assembly has focused on molecular components, many of the most interesting applications of self-assembling processes can be found at larger sizes (nanometers to micrometers). These larger systems also offer a level of control over the characteristics of the components and over the interactions among them that makes fundamental investigations especially tractable.

/pdf/beyond-molecules-self-assembly-of-mesoscopic-and-macroscopic-48ms0goz32.pdf

Beyond molecules: Self-assembly of mesoscopic and macroscopic components

Hydrogen sensors are of increasing importance in connection with the development and expanded use of hydrogen gas as an energy carrier and as a chemical reactant. There are an immense number of sensors reported in the literature for hydrogen detection and in this work these sensors are classified into eight different operating principles. Characteristic performance parameters of these sensor types, such as measuring range, sensitivity, selectivity and response time are reviewed and the latest technology developments are reported. Testing and validation of sensor performance are described in relation to standardisation and use in potentially explosive atmospheres so as to identify the requirements on hydrogen sensors for practical applications.

Hydrogen Sensors - A review

Starting from Tesla's principles of wireless power transfer a century ago, this critical review outlines recent magneto-inductive research activities on wireless power transfer with the transmission distance greater than the transmitter coil dimension. It summarizes the operating principles of a range of wireless power research into 1) the maximum power transfer and 2) the maximum energy efficiency principles. The differences and the implications of these two approaches are explained in terms of their energy efficiency and transmission distance capabilities. The differences between the system energy efficiency and the transmission efficiency are also highlighted. The review covers the two-coil systems, the four-coil systems, the systems with relay resonators and the wireless domino-resonator systems. Related issues including human exposure issues and reduction of winding resistance are also addressed. The review suggests that the use of the maximum energy efficiency principle in the two-coil systems is suitable for short-range rather than mid-range applications, the use of the maximum power transfer principle in the four-coil systems is good for maximizing the transmission distance, but is under a restricted system energy efficiency (<;50%); the use of the maximum energy efficiency principle in relay or domino systems may offer a good compromise for good system energy efficiency and transmission distance on the condition that relay resonators can be placed between the power source and the load.

A Critical Review of Recent Progress in Mid-Range Wireless Power Transfer

A powered surgical stapler is disclosed. The stapler includes a housing, an endoscopic portion extending distally from the housing and defining a first longitudinal axis, a drive motor disposed at least partially within a housing and a firing rod disposed in mechanical cooperation with the drive motor. The firing rod is rotatable by the motor about the first longitudinal axis extending therethrough. The stapler also includes an end effector disposed adjacent a distal portion of the endoscopic portion. The end effector is in mechanical cooperation with the firing rod so that the firing rod drives a surgical function of the end effector. The stapler further includes a control system having a plurality of sensors coupled to the drive motor, the firing rod, the loading unit and the end effector, the plurality of sensors configured to detect operating parameters thereof. The control system also includes a microcontroller coupled to the plurality of sensors and being configured to determine operating status of the powered surgical stapler as a function of the detected operating parameters.

Powered surgical stapling device

Because of the low dimensional power of its force scaling law, surface tension is appropriate for carrying out reshaping and assembly in the microstructure size domain. This paper reviews work on surface tension powered self-assembly of microstructures. The existing theoretical approaches for rotational assembly are unified. The demonstrated fabrication processes are compared. Mechanisms for accurately determining the assembled shape are discussed, and the limits on accuracy and structural distortion are considered. Applications in optics, electronics and mechanics are described. More complex operations (including the combination of self-assembly and self-organization) are also reviewed.

Surface tension-powered self-assembly of microstructures - the state-of-the-art

Overview electromagnetic fields and plane waves material effects the optics of beams reflection and refraction at a single interface the slab waveguide planar waveguide integrated optics optical fibres and fibre devices coupled mode devices optoelectronic interactions in semiconductors optoelectronic devices optic device fabrication systems and applications.

/pdf/optical-guided-waves-and-devices-1w7p32b0qu.pdf

Optical Guided Waves and Devices

Historical background - what is a volume hologram - a first look at gratings - thick periodic structures - two-step processing - volume holography - a brief survey of applications - the organization of the book coupled wave theory - the volume holographic problem - recording the hologram - the coupled wave equations - the diffraction regimes of transmission gratings - two-wave theory - vectorial theory alternative theories - other methods of solution - transparency theory and the optical path method - modal theory - path integration - rigorous methods - non-uniform gratings - two and three-dimensional theory experimental holography - practical techniques - the recording source - laser types - the holographic set-up - testing holograms materials for volume holography - the general characteristics of holographic material - photographic emulsion - dichromated gelatin - photopolymers - photoresist - photochromics - photorefractives planar transmission and reflection holograms - early experiments - what really is inside a volume hologram? - non-linearity, dispersion and non-uniformity - vector effects and internal reflections - optically thin and multilayer holograms superimposed holograms and multiple gratings - sequential and simultaneous recording - general theory for two superimposed gratings - diffraction by two superimposed gratings - spurious waves - N superimposed gratings - holograms of diffuse objects noise gratings - what is a noise grating? - holograms recorded with a single beam - two-beam recording - quantitative analysis - far-field diffraction patterns optical elements - holographic lenses and mirrors - simple theory of holographic imaging - aberration theory and ray tracing - imaging with volume holographic optical elements - applications pictorial holography - improving on the basic display holograms - how does a display hologram work? - advanced recording geometries - multicolour holograms - white-light-viewable transmission holograms - applications gratings in guided wave optics - the principle of wave guidance - co- and contra directional filters - beam deflectors - grating couplers and waveguide holograms - distributed feedback lasers mass-production - replication - copying holograms - methods for surface gratings in integrated optics. Appendices.

Practical Volume Holography

A new surface micromachining process for surface tension powered self-assembly of silicon-based microstructures is described. Mechanical parts are formed from bonded silicon-on-insulator material and rotated out-of-plane by melting photoresist pads at tow temperature. Simple mechanisms that allow accurate control of the final angle are introduced and used to construct fixed 45/spl deg/ mirrors and scanning mirror assemblies.

/pdf/surface-tension-powered-self-assembly-of-3-d-micro-rp1jp3zfb1.pdf

Surface tension powered self-assembly of 3-D micro-optomechanical structures

A wafer-scale, batch fabrication process for constructing quadrupole mass spectrometers using microelectromechanical systems (MEMS) technology is described. The device is formed from two bonded silicon-on-insulator (BSOI) substrates, which are attached together to form a monolithic block. Deep etched features and springs formed in the outer silicon layers are used to locate cylindrical metal electrode rods, while similar features formed in the inner silicon layers are used to define integrated ion entrance and exit optics. The precision of the assembly is determined by lithography and deep etching, and by the mechanical definition of the bonded silicon layers. Mass filtering is demonstrated, with a mass range of /spl ap/ 400 a.m.u. and a mass resolution of 1 a.m.u. at 219 a.m.u., using quadrupoles with rods of 500 /spl mu/m diameter and 30 mm length, operating at 6 MHz RF frequency.

Richard R. A. Syms

Papers

Surface tension-powered self-assembly of microstructures - the state-of-the-art

Optical Guided Waves and Devices

Practical Volume Holography

Surface tension powered self-assembly of 3-D micro-optomechanical structures

Monolithic MEMS quadrupole mass spectrometers by deep silicon etching