A novel concept of a frequency-tuned sub-terahertz gyrotron based on combination an irregular low-frequency resonator and external reflector has been proposed recently. simulation was carried out for fundamental-cyclotron-harmonic that demonstrates the possibility achieving high (10–30%) efficiencies in wide (~10%) frequency range. possible solution to problem narrow-band frequency-tunable refl...

The article proposes the state of the art in techniques and models designed to solve issues in application-layer IP multicast. Specifically, the issue of group communication for distributing video flows using reflectors to participants at a videoconference is considered. A proposed solution is introduced, involving an algorithm capable of dynamically discovering the appropriate reflector to mee...

Vignolini et al. (1) reported the discovery of a multilayer structural reflector in the fruit of the herbaceous perennial Pollia condensata. The structural mechanism is remarkable, with a combination of different cells reflecting left-handed or righthanded circularly polarized light. However, several other significant contributions to the field of structural color deserve to be highlighted alon...

Three-dimensional (3D) backside reflector, compared with flat reflectors, can improve the probability of finding the escape cone for reflecting lights and thus enhance the light-extraction efficiency (LEE) for GaN-based light-emitting diode (LED) chips. A triangle-lattice of microscale SiO2 cone array followed by a 16-pair Ti3O5/SiO2 distributed Bragg reflector (16-DBR) was proposed to be attac...

Conductionor valence-band discontinuities occurring at the junction of two heterogeneous semiconductors can be eliminated by appropriate doping of the inter-facial region. We show by analytic and self-consistent calculations that simultaneous modulation doping and parabolic-compositional grading result in flat band-edge potentials. The new concept is applied to distributed Bragg reflectors for ...

A guided-mode-resonance device for both narrow-band retroreflection and waveguide input coupling was designed fabricated operation wavelength of 1550 nm. It consists a focusing grating coupler (FGC) integrated in cavity resonator constructed by pair distributed Bragg reflectors (DBRs) on reflection substrate. The size the FGC 31 × 20 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:...

Optical reflectors in animals are diverse and ancient. The first image-forming eye appeared around 543 million years ago. This introduced vision as a selection pressure in the evolution of animals, and consequently the evolution of adapted optical devices. The earliest known optical reflectors--diffraction gratings--are 515 Myr old. The subsequent fossil record preserves multilayer reflectors, ...