We demonstrate a compact silicon photonic crystal Mach-Zehnder interferometer operating in the self-collimation regime. By tailoring the photonic band structure such as to produce self-collimated beams, it is possible to design beam splitters and mirrors and combine these to a 20 x 20 microm(2) format. With transmission spectroscopy we find a pronounced unidirectional optical output, the output...

Transition radiation (TR) from ultrarelativistic particles is considered. It is shown that performing collimation of the TR from the periodic N-foil stack (parameters of which are selected in a appropriate manner) one obtains the spectrum of the TR which has a form of a peak position of which ω1 depends on the plasma frequency and the thickness of the radiator foils. The height and width of the...

We present the results of numerical hydrodynamic models for the collimation of outflows from young stellar objects. We show that the presence of a toroidal environment can lead to efficient formation of jets and bipolar outflows from initially uncollimated central winds. The interaction between the wind and the environment leads to two types of collimation, one which is dominated by radiative c...

An electron collimator composed of a point-like source and a parabolic pn junction is proposed as a generator of highly focused electron beams in graphene. The collimator is based on negative refraction and Klein collimation, which are unique to pseudo-relativistic Dirac materials. The electron beams generated by the lensing apparatus can be steered by a weak magnetic field without losing colli...

An activity of many compact objects – Active Galactic Nuclei (AGNs), Young Stellar Objects (YSOs), microquasars – is associated with the highly collimated jets. These jets are thought to be a natural outlet of an excess angular momentum of a central object and accreting matter [1]. The latest observations indicating the jet rotation in AGNs [2] and YSOs [3] support this idea. The most attractiv...

A novel concept of controlled halo removal for intense high-energy beams in storage rings and colliders is presented. It is based on the interaction of the circulating beam with a 5-keV, magnetically confined, pulsed hollow electron beam in a 2-m-long section of the ring. The electrons enclose the circulating beam, kicking halo particles transversely and leaving the beam core unperturbed. By ac...

Intense ion beams with small phase space occupation (high brilliance) are mandatory to keep beam losses low in high current injector accelerators like those planned for the Facility for Antiproton and Ion Research (FAIR). The low energy beam transport from the ion source towards the linac has to keep the emittance growth low and has to support the optimization of the ion source tune. The Frankf...

An acoustic Luneburg lens is a symmetric gradient-index with refractive index decreasing radially from the center to outer surface. It can be used manipulate wave propagation allowing collimation and focusing capabilities. Previously studied lenses based on conventional concept work only at audible frequencies ranging up 15 kHz or single ultrasonic frequency of 40 kHz. In this paper, by tailori...