Phát triển cấu trúc klystron phản xạ sóng siêu nhỏ Dịch bởi AI
J.R. Thorpe, J.R. Fletcher, J.M. Chamberlain, R.E. Miles, J. Garcia-Garcia, C.J. Mann, E. Huq, M. Oldfield, J. Spencer
Bài báo mô tả quá trình phát triển cấu trúc klystron phản xạ sóng siêu nhỏ được
vi gia công. Một phân tích tổng quan về những vấn đề lý thuyết chính, chẳng hạn
như dao động và điều kiện khởi động, cũng như cách mà công suất đầu ra tỷ lệ với
tần số. Hai kỹ thuật để hiện thực hóa lắp ráp khoang cộng hưởng được nêu ra.
Phương pháp được ưa chuộng dẫn đến khoang tái nhập bằng vàng có thể đứng riêng
biệ... hiện toàn bộ
#Klystrons #Radio frequency #Electrons #Micromachining #Optical modulation #Resonance #Assembly #Gold #Astronomy #Low voltage
Terahertz time-domain spectroscopic study of ferroelectrics
S. Nishizawa, H. Kitahara, N. Tsumura, M.W. Takeda, S. Kojima
A new compact instrument of terahertz time-domain spectrometry (THz-TDS) has
been developed to expand the THz-TDS adaptation for far-infrared quantitative
measurements on functional materials. THz-TDS enables us to measure
simultaneously the spectral amplitude and phase shift in the far-infrared region
between 1 and 100 cm/sup -1/ so that the real and imaginary parts of complex
dielectric function... hiện toàn bộ
#Time domain analysis #Spectroscopy #Ferroelectric materials #Instruments #Dielectric measurements #Submillimeter wave measurements #Dielectric materials #Phase measurement #Amplitude estimation #Phase estimation
High performance HBV multipliers monolithically integrated onto a host quartz substrate
T. David, S. Arscott, J.-M. Munier, T. Decoopman, T. Akalin, P. Mounaix, X. Melique, O. Vanbesien, G. Beaudin, D. Lippens
Fully integrated monolithic circuits incorporating InP-based heterostructure
barrier varactor (HBV) frequency multipliers have been fabricated via epitaxial
lift-off and transfer-substrate techniques onto a quartz substrate. We have
obtained a maximum output power of 6 mW at 288 GHz corresponding to an overall
efficiency of 6%. In addition we have observed a 45 GHz 3 dB bandwidth centered
around 3... hiện toàn bộ
#Substrates #Frequency #Circuits #Diodes #Indium gallium arsenide #Varactors #Bandwidth #Matched filters #Filtering #Millimeter wave devices
Self-consistent rate equation modelling of a Terahertz GaAs/AlGaAs quantum-cascade laser
D. Indjin, P. Harrison, R.W. Kelsall, Z. Ikonic
In this work, electron transport in GaAs/AlGaAs quantum cascade lasers operating
at far-infrared wavelengths is calculated self-consistently using an
intersubband scattering model. Subband populations and carrier transition rates
are calculated and all relevant electron-electron and electron-LO phonon
scatterings between the injector/collector and active region levels (13-levels
in total) are incl... hiện toàn bộ
#Equations #Gallium arsenide #Laser modes #Quantum cascade lasers #Particle scattering #Electrons #Phonons #Laser transitions #Temperature distribution #Threshold current
Novel concept for THz-photomixer based on periodically doped heterostructures and quasi ballistic transport
M. Eckardt, A. Schwanhausser, F. Renner, L. Robledo, A. Friedrich, P. Pohl, P. Kiesel, S. Malzer, G.H. Dohler, D. Driscoll, M. Hanson, A.C. Gossard
Reports on a new concept for THz photomixers, which are not (as usually)
frequency limited by the carrier lifetime in low-temperature-grown GaAs. The
concept is based on ballistic electron transport in a periodically doped
heterostructure (p-i-n-p-i-n-superlattice) and allows for impedance matching to
the attached antenna.
#Gallium arsenide #Charge carrier processes #Spontaneous emission #Ballistic transport #Frequency #Charge carrier lifetime #Electron mobility #Space charge #Power lasers #Impedance matching
Achromatically injection-seeded terahertz-wave parametric generator
K. Imai, K. Kawase, H. Minamide, H. Ito
An achromatically injection-seeded terahertz-wave parametric generator (ais-TPG)
was constructed using MgO:LiNbO/sub 3/ crystals and a tunable seeder using a
stationary dispersion-compensated optical arrangement. Without readjusting the
mirrors, smooth tuning of the terahertz-wave over the 0.6/spl sim/2.6 THz range
was obtained by adjusting the seeder wavelength alone. The feasibility of this
syst... hiện toàn bộ
#Optical frequency conversion #Gratings #Tunable circuits and devices #Laser tuning #Optical resonators #Frequency conversion #Telescopes #Lenses #Nonlinear optics #Optical pumping
Conventional and novel approaches to RF power generation with two-terminal devices at terahertz frequencies
H. Eisele
Recent advances in design and technology significantly improved the performance
of low-noise InP Gunn devices in oscillators at W-band (75-110 GHz) and D-band
(110-170 GHz) frequencies. More importantly, they resulted in orders of
magnitude higher radio-frequency (RF) output power levels above D-band. Examples
are continuous-wave RF power levels of more than 30 mW at 193 GHz, more than 3
mW at 300... hiện toàn bộ
#Radio frequency #Power generation #Indium phosphide #Gunn devices #Oscillators #Diodes #Gallium arsenide #Submillimeter wave technology #Superlattices #Gallium nitride
Optically pumped terahertz silicon lasers
S.G. Pavlov, H.-W. Hubers, R.Kh. Zhukavin, E.E. Orlova, H. Riemann, V.N. Shastin
Photoexcitation of shallow impurity centers in silicon at low temperatures (<10
K) yields stimulated emission from intra-center optical transitions in the
terahertz range. The population inversion mechanisms are based on the
peculiarities of electron-phonon interaction, leading to the existence of either
a relatively long-living excited impurity state or a group of unpopulated
impurity states.
#Optical pumping #Laser excitation #Silicon #Pump lasers #Semiconductor lasers #Stimulated emission #Semiconductor impurities #Laser transitions #Quantum cascade lasers #Optical sensors
Electric field dependence of pulsed THz emission from photoconductive antennas
C. Baker, C.E. Norman, J.A. Cluff, W.R. Tribe, B.E. Cole, E.H. Linfield, A.G. Davies, D.D. Arnone, M. Pepper
It has been postulated that terahertz (THz) generation in photoconductive
emitters is associated with electric field transients between the electrodes of
the device. This is supported by experimental measurements showing enhanced
generation with near-anode device excitation. In this work we present a detailed
analysis of the dependence of device performance on the position of laser
excitation for ... hiện toàn bộ
#Photoconductivity #Switches #Laser mode locking #Power system transients #Anodes #Substrates #Laser excitation #Bandwidth #Semiconductor lasers #Dipole antennas
Intra- and extra-cavity THz generation from optically and electrically confined photoconducting layers [GaAs]
J. Darmo, T. Muller, G. Strasser, K. Unterraner, T. Le, G. Tempea, A. Stingl
A photoconductive terahertz generator with an integrated Bragg mirror is
presented. The generator exhibits significantly improved performance. We
demonstrate for the first time intra-cavity THz generation using this type of
photoconductive emitter.
#Photoconductivity #Gallium arsenide #Mirrors #Substrates #Optical pulse generation #Ultrafast optics #Power generation #Integrated optics #Optical modulation #Molecular beam epitaxial growth