scholarly journals Monolithic Patch-Antenna THz Lasers with Extremely Low Beam Divergence and Polarization Control

ACS Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 412-417
Author(s):  
Joel Pérez-Urquizo ◽  
Yanko Todorov ◽  
Lianhe Li ◽  
Alexander G. Davies ◽  
Edmund H. Linfield ◽  
...  
Keyword(s):  
Patch Antenna ◽  
Beam Divergence ◽  
Polarization Control

Engineering the Losses and Beam Divergence in Arrays of Patch Antenna Microcavities for Terahertz Sources

2017 ◽  
Vol 38 (11) ◽  
pp. 1321-1330 ◽  
Author(s):  
Julien Madéo ◽  
Joel Pérez-Urquizo ◽  
Yanko Todorov ◽  
Carlo Sirtori ◽  
Keshav M. Dani
Keyword(s):  
Patch Antenna ◽  
Beam Divergence ◽  
Terahertz Sources

Spatial resolution of X-ray microanalysis in thin foils

1978 ◽  
Vol 36 (1) ◽  
pp. 544-545
Author(s):  
R. Hutchings ◽  
I.P. Jones ◽  
M.H. Loretto ◽  
R.E. Smallman
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
Beam Divergence ◽  
Inelastic Interaction ◽  
Specimen Thickness ◽  
High Current ◽  
Beam Spreading ◽  
X Ray ◽  
Thin Foils ◽  
Complex Calculation

There is increasing interest in X-ray microanalysis of thin specimens and the present paper attempts to define some of the factors which govern the spatial resolution of this type of microanalysis. One of these factors is the spreading of the electron probe as it is transmitted through the specimen. There will always be some beam-spreading with small electron probes, because of the inevitable beam divergence associated with small, high current probes; a lower limit to the spatial resolution is thus 2αst where 2αs is the beam divergence and t the specimen thickness.In addition there will of course be beam spreading caused by elastic and inelastic interaction between the electron beam and the specimen. The angle through which electrons are scattered by the various scattering processes can vary from zero to 180° and it is clearly a very complex calculation to determine the effective size of the beam as it propagates through the specimen.

Electron Channelling Contrast Imaging of Dislocations

1990 ◽  
Vol 48 (1) ◽  
pp. 600-601
Author(s):  
J.T. Czernuszka ◽  
N.J. Long ◽  
P.B. Hirsch
Keyword(s):  
Field Emission ◽  
Secondary Electron ◽  
Surface Defects ◽  
Spot Size ◽  
Beam Divergence ◽  
Contrast Imaging ◽  
Scattered Electron ◽  
Near Surface ◽  
Filter System ◽  
Electron Channelling

In the 1970s there was considerable interest in the development of the electron channelling contrast imaging (ECCI) technique for imaging near surface defects in bulk (electron opaque) specimens. The predictions of the theories were realised experimentally by Morin et al., who used a field emission gun (FEG) operating at 40-50kV and an energy filter such that only electrons which had lost no more than a few 100V were detected. This paper presents the results of a set of preliminary experiments which show that an energy filter system is unneccessary to image and characterise the Burgers vectors of dislocations in bulk specimens. The examples in the paper indicatethe general versatility of the technique.A VG HB501 STEM with a FEG was operated at 100kV. A single tilt cartridge was used in the reflection position of the microscope. A retractable back-scattered electron detector was fitted into the secondary electron port and positioned to within a few millimetres of the specimen. The image was acquired using a Synoptics Synergy framestore and digital scan generator and subsequently processed using Semper 6. The beam divergence with the specimen in this position was 2.5 mrads with a spot size of approximately 4nm. Electron channelling patterns were used to orientate the sample.

Control of proton beam divergence in intense-laser foil-plasma interaction

2006 ◽  
Vol 133 ◽  
pp. 549-551 ◽  
Author(s):  
S. Kawata ◽  
R. Sonobe ◽  
S. Miyazaki ◽  
K. Sakai ◽  
T. Kikuchi
Keyword(s):  
Proton Beam ◽  
Beam Divergence ◽  
Intense Laser ◽  
Plasma Interaction

Metamaterial Structure with Negative μ and ε for reduction of return loss of Microstrip Patch Antenna

2012 ◽  
Vol 2 (8) ◽  
pp. 130-133
Author(s):  
Amandeep Singh Amandeep Singh ◽  
◽  
Sankul Agarwal ◽  
Vaibhav Sharma ◽  
Shivam Pandita
Keyword(s):  
Patch Antenna ◽  
Return Loss ◽  
Microstrip Patch Antenna ◽  
Metamaterial Structure ◽  
Microstrip Patch
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