WIDELY-TUNABLE, MONOCHROMATIC, AND HIGH-POWER TERAHERTZ SOURCES AND THEIR APPLICATIONS

2003 ◽  
Vol 12 (04) ◽  
pp. 557-585 ◽  
Author(s):  
YUJIE J. DING ◽  
WEI SHI
Keyword(s):  
Peak Power ◽  
Difference Frequency Generation ◽  
Thz Radiation ◽  
Narrow Linewidth ◽  
Nonlinear Materials ◽  
Peak Output Power ◽  
Output Peak Power ◽  
Conversion Efficiencies ◽  
Coherence Lengths ◽  
High Coherence

We have demonstrated that coherent terahertz (THz) waves can be efficiently generated and tuned in extremely-wide ranges based on phase-matched difference-frequency generation (DFG) in second-order nonlinear materials. Among all the nonlinear crystals available, we have chosen GaSe and ZnGeP 2, which correspond to two of the best nonlinear materials for the efficient THz generation. This is due to the fact that these two materials have the lowest and next-to-lowest absorption coefficients in the THz domain. In addition, they possess large nonlinear coefficients. For a single GaSe crystal, continuously-tunable and coherent radiation in the extremely-wide ranges of 2.7–38.4 μ m and 58.2–3540 μ m has been achieved. Hence, a novel and promising THz source is finally available. This source has the additional advantages of high coherence (narrow linewidth) and simple alignment. The peak output power for the THz radiation reaches 209 W at the wavelength of 196 μ m (1.53 THz), which corresponds to a power conversion efficiency of 0.055%. On the other hand, for a single ZnGeP 2 crystal we have efficiently generated a monochromatic THz wave continuously-tunable in the ranges of 83.1–1642 μ m and 80.2–1416 μ m . The highest output peak power achieved so far is 134 W. We have also investigated how to use THz waveguides and long coherence lengths for improving the conversion efficiencies. We have reviewed our results on some important applications using these unique sources.

Selection of Optimum Nonlinear Crystals for Efficient Parametric Generation and Sensitive Detection of Monochromatic ns THz Pulses

2007 ◽  
Vol 1016 ◽  
Author(s):  
Yujie J. Ding
Keyword(s):  
Conversion Efficiency ◽  
Peak Power ◽  
Difference Frequency Generation ◽  
Beam Parameter ◽  
High Peak Power ◽  
Parametric Generation ◽  
Output Wavelength ◽  
Output Peak Power ◽  
Photon Conversion ◽  
Selection Of

AbstractWe report our recent progress made on the development of widely-tunable monochromatic THz sources. They have been realized based on difference-frequency generation (DFG) in GaSe, ZnGeP2, and GaP crystals, respectively. Using a GaSe crystal, the output wavelength was tuned continuously in the range from 66.5 µm to 5664 µm (from 150 cm-1 to 1.77 cm-1) with the peak power reaching 389 W. Such a high peak power corresponds to a conversion efficiency of about 0.1% (a photon conversion efficiency of 19%). A further optimization on the THz beam parameter may result in an output peak power of a few kW. Within the range of 100-250 µm the output peak powers were higher than 100 W. We have also investigated THz frequency upconversion in GaSe, ZnGeP2, and GaP crystals. Such a parametric process has a potential for detecting THz pulses at room temperature or just using a thermoelectric cooler. The minimum detectable energy per pulse was measured to be 245 pJ, which corresponds to a noise equivalent energy of 77.5 . A further optimization of the process can reduce this value down to 1 .

scholarly journals Design of a Pre-Bunched THz Free Electron Laser

Particles ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 267-278 ◽  
Author(s):  
Ruixuan Huang ◽  
Weiwei Li ◽  
Zhouyu Zhao ◽  
Heting Li ◽  
Jigang Wang ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Peak Power ◽  
Tuning Range ◽  
Second Harmonic ◽  
Industrial Applications ◽  
Thz Radiation ◽  
Fundamental Wave ◽  
Electron Dynamics ◽  
Main Components

Terahertz (THz) radiation has attracted much attention in new scientific and industrial applications. There has been significant recent progress in generating THz with accelerators. To investigate the collective behavior of electron dynamics, we have proposed a new high throughput material characterization system, which supplies a multiple light source. The system includes a pre-bunched THz free electron laser (FEL), which is a high-power narrow-band THz source with a wide tuning range of frequency. The physical design with the main components of the facility is introduced, and the simulation results are illustrated. Radiation of 0.5–3.0 THz is obtained by the fundamental wave of the pre-bunched beam, and radiation covering 3.0–5.0 THz is realized by second harmonic generation. As the simulation shows, intense THz radiation could be achieved in a frequency from 0.5–5.0 THz, with a peak power of several megawatts (MWs) and a bandwidth of a few percent.

High Peak-Power Narrow Linewidth 1.9 μm Fiber Gas Raman Source

2016 ◽  
Author(s):  
Bo Gu ◽  
Yubin Chen ◽  
Zefeng Wang ◽  
Fei Yu ◽  
Chaofan Zhang
Keyword(s):  
Peak Power ◽  
High Peak ◽  
High Peak Power ◽  
Narrow Linewidth

scholarly journals Terahertz Generation in an Electrically Biased Optical Fiber: A Theoretical Investigation

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Montasir Qasymeh
Keyword(s):  
Optical Fiber ◽  
Wide Spectrum ◽  
Single Mode ◽  
Difference Frequency Generation ◽  
Phase Match ◽  
Single Mode Fiber ◽  
Nonlinear Susceptibility ◽  
Thz Radiation ◽  
Novel Approach ◽  
Proper Design

We propose and theoretically investigate a novel approach for generating terahertz (THz) radiation in a standard single-mode fiber. The optical fiber is mediated by an electrostatic field, which induces an effective second-order nonlinear susceptibility via the Kerr effect. The THz generation is based on difference frequency generation (DFG). A dispersive fiber Bragg grating (FBG) is utilized to phase match the two interacting optical carriers. A ring resonator is utilized to boost the optical intensities in the biased optical fiber. A mathematical model is developed which is supported by a numerical analysis and simulations. It is shown that a wide spectrum of a tunable THz radiation can be generated, providing a proper design of the FBG and the optical carriers.

scholarly journals Generation of 130 W narrow-linewidth high-peak-power picosecond pulses directly from a compact Yb-doped single-stage fiber amplifier

2015 ◽  
Vol 54 (9) ◽  
pp. 096106 ◽  
Author(s):  
Yaoyao Qi ◽  
Haijuan Yu ◽  
Jingyuan Zhang ◽  
Lei Wang ◽  
Ling Zhang ◽  
...  
Keyword(s):  
Peak Power ◽  
Fiber Amplifier ◽  
Single Stage ◽  
High Peak ◽  
High Peak Power ◽  
Narrow Linewidth ◽  
Picosecond Pulses

scholarly journals Design of Direct Injection Jet Ignition High Performance Naturally Aspirated Motorcycle Engines

Designs ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 11
Author(s):  
Albert Boretti
Keyword(s):  
Conversion Efficiency ◽  
Peak Power ◽  
High Performance ◽  
Direct Injection ◽  
Fuel Efficiency ◽  
Specific Power ◽  
Optimized Design ◽  
Fuel Conversion ◽  
Specific Power Density ◽  
Conversion Efficiencies

Thanks to the adoption of high pressure, direct injection and jet ignition, plus electrically assisted turbo-compounding, the fuel conversion efficiency of Fédération Internationale de l'Automobile (FIA) F1 engines has been spectacularly improved up to values above 46% peak power, and 50% peak efficiency, by running lean of stoichiometry stratified in a high boost, high compression ratio environment. Opposite, Federation Internationale de Motocyclisme (FIM) Moto-GP engines are still naturally aspirated, port injected, spark ignited, working with homogeneous mixtures. This old fashioned but highly optimized design is responsible for relatively low fuel conversion efficiencies, and yet delivers an outstanding specific power density of 200 kW/liter. The potential to improve the fuel conversion efficiency of Moto-GP engines through the adoption of direct injection and jet ignition, prevented by the current rules, is herein discussed based on simulations. As two-stroke engines may benefit from direct injection and jet ignition more than four-stroke engines, the opportunity of a return of two-stroke engines is also argued, similarly based on simulations. About the same power, but at a better fuel efficiency, of today’s 1000 cm3 four stroke engines, may be obtained with lean stratified direct injection jet ignition engines, four-stroke of 1450 cm3, or two-stroke of 1050 cm3. About the same power and fuel efficiency may also be delivered with stoichiometric engines direct injection jet ignition two-stroke of 750 cm3.

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