T-Wave Generation & Detection
My research focuses on the modeling, the design and the optimization of terahertz waveguide frequency multipliers used to build local oscillators of heterodyne receivers dedicated to Astrophysics, Planetology and the Science of the Atmosphere. I am also interested in the design and the optimization of low-noise THz mixers for planetary missions.
I started a program in October 2006 at the Observatoire de Paris in partnership with Laboratoire de Photonique et de Nanostructures-CNRS, now Centre de Nanosciences et de Nanotechnologies (group of Dr. Yong Jin), to fabricate nano-scale Schottky diodes on GaAs membranes. A permanent staff member of LERMA, Dr. Lina Gatilova, developed the process at C2N-Marcoussis with the technical support of several staff members of C2N. The epilayer growth on GaAs substrates was made by Dr. Antonella Cavanna, a permanent staff member of C2N.
In 2015, LERMA instrumentation group demonstrated the world’s most sensitive 520-620GHz Schottky receiver with 1070-1500K DSB noise temperature at an ambient temperature of 295K. When cooled to 135K, the receiver noise temperature dropped by a factor close to two.
In 2016, LERMA, in partnership with C2N, demonstrated the feasibility in Europe of SWI 1080-1275GHz receiver, with performances within the specifications of the instrument (less than 4000K of receiver double side band noise temperature at an ambient temperature of 150K±10K).
In May 2017, with a new generation of 1200GHz Schottky mixer devices fabricated at C2N-Marcoussis, LERMA demonstrated the world’s most sensitive Schottky receiver working in the 1080-1275GHz band, with an average double-side-band receiver equivalent noise temperature of 1950K across the band with a standard deviation of 220K at an ambient temperature of 150K±10K.
Generation of coherent waves at terahertz frequencies & THz mixers for low noise heterodyne receivers
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JUICE-SWI 1200GHz receiver frontend development
LERMA instrumentation group is now responsible of delivering the high frequency part of JUICE-SWI 1200GHz channel to the SWI consortium. CN2 is the partner of LERMA for this major scientific space program. JUICE-SWI will be the first instrument of this type to observe a planet with such a high spatial resolution.
LERMA 1200GHz mixer for JUICE-SWI relies on sub-micron Schottky diodes on a thin GaAs membrane, fabricated at C2N using only e-beam lithography. The mixer features an on-chip capacitor, located on one of the mesas, to bias the pair of diodes.
LERMA bias-able 1200GHz sub-harmonic mixer can be pumped with very low Local Oscillator power at 600GHz, below 1mW. This is due to the low intrinsic capacitance of the diodes and the low level of parasitics, but also to a novel mixer design that allows to cover the full 1080-1275GHz range with state-of-the-art noise performance and flat performance across the band. A record double side band receiver noise temperature of T_rec_DSB=1600K has been recorded at 1114GHz at an ambient temperature of 150K with 1600K ≤T_rec_DSB≤2570K across the entire band with an average of 1950K and a standard deviation of 220K.
This research is financed by the Centre National d’Études Spatiale (CNES), the Centre National de la Recherche Scientifique (CNRS) and the European Space Agency.
