scholarly journals Novel Schemes for Compact FELs in the THz Region

2019 ◽  
Vol 4 (4) ◽  
pp. 90
Author(s):  
Andrea Doria ◽  
Gian Piero Gallerano ◽  
Emilio Giovenale
Keyword(s):  
Pulse Duration ◽  
Free Electron ◽  
Continuous Wave ◽  
Industrial Applications ◽  
Wide Frequency Range ◽  
Free Electrons ◽  
Cw Operation ◽  
Power Peak ◽  
Compact Sources ◽  
Radiation Time

The rapid advance of terahertz technologies in terms of radiation generators, systems, and scientific or industrial applications has put a particular focus on compact sources with challenging performances in terms of generated power (peak and/or average), radiation time structure, and frequency band tunability. Free electron laser (FEL)-based sources are probably the best candidates to express such a versatility; there are a number of schemes that have been investigated over the years to generate coherent radiation from free electrons in the mm-wave and terahertz regions of the spectrum, covering a wide frequency range from approximately 100 GHz to 10 THz. This paper proposes novel schemes for exploring the limits in the performance of radio frequency-driven free-electron devices in terms of ultrashort pulse duration, wide bandwidth operation, and energy recovery for near continuous wave (CW) operation. The aim of the present work is to demonstrate the feasibility of an FEL achieving performance comparable to a conventional photoconductive THz source, which is commonly used for time-domain spectroscopy (TDS), in terms of bandwidth and pulse duration. We will also demonstrate that a THz FEL could be very powerful and flexible in terms of tailoring its spectral features.

scholarly journals Shaping quantum photonic states using free electrons

2021 ◽  
Vol 7 (11) ◽  
pp. eabe4270 ◽  
Author(s):  
A. Ben Hayun ◽  
O. Reinhardt ◽  
J. Nemirovsky ◽  
A. Karnieli ◽  
N. Rivera ◽  
...  
Keyword(s):  
Free Electron ◽  
Degrees Of Freedom ◽  
Free Electrons ◽  
Complete Control ◽  
Fock State ◽  
Judicious Choice ◽  
Electron Microscopes ◽  
Photonic States ◽  
Photonic Cavities ◽  
Electron Interactions

It is a long-standing goal to create light with unique quantum properties such as squeezing and entanglement. We propose the generation of quantum light using free-electron interactions, going beyond their already ubiquitous use in generating classical light. This concept is motivated by developments in electron microscopy, which recently demonstrated quantum free-electron interactions with light in photonic cavities. Such electron microscopes provide platforms for shaping quantum states of light through a judicious choice of the input light and electron states. Specifically, we show how electron energy combs implement photon displacement operations, creating displaced-Fock and displaced-squeezed states. We develop the theory for consecutive electron-cavity interactions with a common cavity and show how to generate any target Fock state. Looking forward, exploiting the degrees of freedom of electrons, light, and their interaction may achieve complete control over the quantum state of the generated light, leading to novel light statistics and correlations.

scholarly journals Development of mini-undulators for a table-top free-electron laser

2018 ◽  
Vol 36 (3) ◽  
pp. 396-404
Author(s):  
G. Petrov ◽  
J. Davis ◽  
W. Schumaker ◽  
M. Vargas ◽  
V. Chvykov ◽  
...  
Keyword(s):  
Free Electron ◽  
Permanent Magnets ◽  
Laser Machining ◽  
University Of Michigan ◽  
X Ray ◽  
The Past ◽  
Laser Wakefield ◽  
Electron Propagation ◽  
The University ◽  
Compact Sources

AbstractThe development of laser wakefield accelerators (LWFA) over the past several years has led to an interest in very compact sources of X-ray radiation – such as “table-top” free electron lasers. However, the use of conventional undulators using permanent magnets also implies system sizes which are large. In this work, we assess the possibilities for the use of novel mini-undulators in conjunction with a LWFA so that the dimensions of the undulator become comparable with the acceleration distances for LWFA experiments (i.e., centimeters). The use of a prototype undulator using laser machining of permanent magnets for this application is described and the emission characteristics and limitations of such a system are determined. Preliminary electron propagation and X-ray emission measurements are taken with a LWFA electron beam at the University of Michigan.

scholarly journals Room Temperature CW Operation of GaN-based Blue Laser Diodes by GaInN/GaN optical guiding layers

2000 ◽  
Vol 5 (S1) ◽  
pp. 1-7 ◽  
Author(s):  
Masayoshi Koike ◽  
Shiro Yamasaki ◽  
Yuta Tezen ◽  
Seiji Nagai ◽  
Sho Iwayama ◽  
...  
Keyword(s):  
Room Temperature ◽  
Continuous Wave ◽  
Laser Diodes ◽  
Threshold Current ◽  
Crystal Defects ◽  
Blue Laser ◽  
Buffer Layers ◽  
Continuous Wave Laser ◽  
Cw Operation ◽  
First Time

GaN-based short wavelength laser diodes are the most promising key device for a digital versatile disk. We have been improving the important points of the laser diodes in terms of optical guiding layers, mirror facets. The continuous wave laser irradiation at room temperature could be achieved successfully by reducing the threshold current to 60 mA (4 kA/cm2). We have tried to apply the multi low temperature buffer layers to the laser diodes for the first time to reduce the crystal defects.

Accelerator-based X-ray sources: synchrotron radiation, X-ray free electron lasers and beyond

2019 ◽  
Vol 377 (2147) ◽  
pp. 20180231 ◽  
Author(s):  
Tetsuya Ishikawa
Keyword(s):  
Synchrotron Radiation ◽  
Storage Ring ◽  
Free Electron ◽  
Continuous Wave ◽  
Transitional Period ◽  
Light Sources ◽  
X Rays ◽  
Free Electron Lasers ◽  
Beam Emittance ◽  
X Ray

The evolution of synchrotron radiation (SR) sources and related sciences is discussed to explain the ‘generation’ of the SR sources. Most of the contemporary SR sources belong to the third generation, where the storage rings are optimized for the use of undulator radiation. The undulator development allowed to reduction of the electron energy of the storage ring necessary for delivering 10 keV X-rays from the initial 6–8 GeV to the current 3 Gev. Now is the transitional period from the double-bend-achromat lattice-based storage ring to the multi-bend-achromat lattice to achieve much smaller electron beam emittance. Free electron lasers are the other important accelerator-based light sources which recently reached hard X-ray regime by using self-amplified spontaneous emission scheme. Future accelerator-based X-ray sources should be continuous wave X-ray free electron lasers and pulsed X-ray free electron lasers. Some pathways to reach the future case are discussed. This article is part of the theme issue ‘Fifty years of synchrotron science: achievements and opportunities’.

scholarly journals Pulse duration and wavelength stability measurements of a midinfrared free-electron laser

2013 ◽  
Vol 38 (7) ◽  
pp. 1068 ◽  
Author(s):  
Yu Qin ◽  
Heishun Zen ◽  
Xiaolong Wang ◽  
Toshiteru Kii ◽  
Takashi Nakajima ◽  
...  
Keyword(s):  
Pulse Duration ◽  
Free Electron ◽  
Free Electron Laser ◽  
Stability Measurements

scholarly journals On some electron properties of tellurium and Wilson's mechanism of semi-conductivity

1935 ◽  
Vol 148 (865) ◽  
pp. 648-664 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Free Electron ◽  
Previous Investigation ◽  
Room Temperature ◽  
Specific Resistance ◽  
Mean Free Path ◽  
Free Electrons ◽  
Conduction Electrons ◽  
Classical Statistics ◽  
Limiting Case

In a previous investigation it was found that the unusually high value for the Wiedemann-Franz ratio of tellurium could be explained as being only a formal anomally. The amount of heat transferred by the bound atoms is the same in tellurium as in conducting metals; but, in tellurium, in contrast to good conductors, it is responsible for almost the entire heat conductivity because the heat transferred by the free electrons is especially small. This indicates that tellurium differs from true metals in that the density of free electrons is very small. Classical statistics is therefore applicable and the electrical conductivity is given by x = 4/3 e 2 ln (2 πmk T) -5/9 , (1) where n is the density of free (conduction) electrons and l is their mean free path. Taking the specific resistance of tellurium at room temperature as 0.3 ohm-cm and l as 5.2 X 10 -6 cm (Sommerfeld's value for silver, found by applying Fermi-Dirac statistics), n is 2.9 X 10 16 , or about one free electron per million tellurium atoms in contrast to good conductors in which there is approximately one free electron per atom. Even in the limiting case with l = 3.2 X 10 -3 cm (the distance between the tellurium atoms), n is 4.7 X 10 18 which is about one free electron for every 6000 tellurium atoms.

scholarly journals Pulse control in a wide frequency range for a quasi-continuous wave diode-pumped cesium atom vapor laser by a pump modulation in the spectral domain

2018 ◽  
Vol 26 (20) ◽  
pp. 26679 ◽  
Author(s):  
Seongjin Hong ◽  
Byungjoo Kong ◽  
Yong Soo Lee ◽  
Sanggwon Song ◽  
Seokjin Kim ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Wide Frequency Range ◽  
Cesium Atom ◽  
Spectral Domain ◽  
Pulse Control ◽  
Frequency Range ◽  
Vapor Laser ◽  
Diode Pumped
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