The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We report our investigation on low-temperature-grown GaAs THz photomixers using two different kind of antennas: silicon lens coupled spiral antenna and transverse electromagnetic horn antenna. We demonstrate that the horn radiates more power than the spiral above 600 GHz and at 2 THz the improvement is about a decade.
We have developed an epitaxial layer transfer technique for THz devices. Here we report the fabrication and the characterization of a THz photomixer on a silicon substrate. The active part of the photomixer is a low-temperature-grown GaAs mesa which has been transferred and layer bonded onto a Si substrate. The preliminary measurement of the THz signal generated in a photomixing configuration at 0...
We report on-wafer measurements of planar transmission lines on quartz substrate at J-band. We have fabricated and characterized as well CPW than Planar Goubau-Sommerfeld Lines (PGSL) up to 325 GHz. The transmission level is relatively good for straight PGSL but we can notice higher losses for structures with two 90deg-bendings. Different metallization have also been used for the study of metallic...
We report our investigation on realization of 1.55 mum wavelengths sensitive photomixer based on GaAsSb/InP uni-travelling-carrier photodiode. The epitaxial structure and technological steps are described.
The investigation of THz generation using low-temperature-grown GaAs (LTG-GaAs) photoconductors integrated with horn antennas is reported. Results obtained using a photomixing experiment are presented. A maximum generated power of 1 muW at 780 GHz was achieved for an optical power of 2times80 mW and a photocurrent of 1 mA.
We present the operation and the far field radiation pattern of a 2.9 THz double metal quantum cascade laser (QCL) with a micro TEM-horn antenna. An improvement of both the radiation pattern and the collected power level (typically a factor of 2 with f/1 optics) are observed in comparison with the QCL without antenna.
In this communication, we present THz planar strip plasmonic (THz-PSP) structures based on planar Goubau lines (PGL). In order to improve different propagation characteristics, a membrane approach is studied because it is more convenient for low dispersion propagation and for a long range plasmonic behaviour. Resonating structures such as split ring resonators (SRR) along the plasmonic waveguide can...
Photomixers that consist in a uni-travelling-carrier photodiode (UTC-PD) integrated with a TEM horn antenna (TEM-HA) have been realized and characterized.
The fabrication of InGaAs/InP uni-travelling-carrier photodiodes integrated with broadband horn antennas and demonstration of photomixing up to 1.8THz are reported. A radiated power of 1.1 μW at 940 GHz was measured for a photocurrent of only 2.75 mA (50 mW optical power), demonstrating the high efficiency of the device. The conversion efficiency obtained has been increased by more than a decade compared...
A horn-antenna is integrated on a microstrip waveguide QCL emitting at 2.0 THz. This allows a better impedance match to free space, which improves substantially the directivity of the beam and the radiation outcoupling.
We have fabricated and characterized with electroabsorption sampling uni-travelling-carrier photodiodes. This 7.5 mum-diameter photodiode generates electrical pulses with full width at half maximum of 3.1 ps.
We have studied a new kind of terahertz antenna: transverse electromagnetic horn antennas (TEM-HA). These antennas have interesting characteristics for THz applications: large bandwidth, low reflection coefficient, good directivity and low dispersion. TEM-HA have been designed by simulation and measured thanks to a time-domain experiment. The reflection coefficient is less than -10 dB at frequencies...
Quantum Cascade Lasers are one the most promising approach for the generation of THz waves and particularly in a double plasmon waveguide topology. Stripline resonators with a quasi-TEM mode are indeed interesting for THz-QCLs thanks to a high confinement factor combined with low losses. However they present two major drawbacks: the first is a poor outcoupling of the radiation, and the second is a...
In this communication, we present measurement results on THz Planar Strip Plasmonic (THz-PSP) structures based on Planar Goubau Lines (PGL). The first part will be dedicated to the study of bendings (90deg for example) and the second one to filters fabricated with a corrugated PGL. We demonstrate low loss bendings with highly confined electromagnetic waves. For the second part two different topologies...
We present measurements and electromagnetic simulations of planar Goubau lines (PGL) on quartz substrate up to 1 THz. PGLs are single strip transmission lines. A very high-efficiency planar transition between a standard coplanar waveguide (CPW) and PGL is demonstrated A time-domain electroabsorption sampling method is used to measure the reflected and transmitted waveforms. Transmission of picosecond...
The generation of continuous coherent THz radiation by mixing two cw Ti:Sa laser beams with a well-controlled frequency separation for a new scheme of vertically integrated low temperature grown GaAs (LTG-GaAs) spiral photomixer is reported. For this new photomixer device used in THz emission, the LTG-GaAs active layer is sandwiched between the two parallel metal plates of a high-speed photodetector...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.