Experimental techniques & lectures
- 1. THz time-domain spectroscopy (TDS) & data analysisN°1
The aim of this short course is to present THz TDS from concepts to applications, focusing on spectroscopy in the time-domain. A lecture will present the TDS set-up and its components, the advantages and drawbacks of the techniques followed by a presentation of the data treatment for refractive index or other material/metamaterial parameters retrieving. Finally, we will give a brief overview of the possible applications.
The participants will align the quasi-optics THz bench, perform the TDS experiments and analyze the data
- 2. Electro-optic and photoconductive sampling of sub-mm and THz wavesN°2
The aim of this short course is to provide a comprehensive introduction to the two mainstream techniques exploited for the optical sampling of THz and sub-mm waves with the help of mode-locked fs-lasers or CW diode lasers (heterodyne mixing). A special emphasis will be put on the sampling of CW sources.
The participants will have the possibility to set-up THz-sampling systems relying on electro-optic crystals and state of the art photomixers and to measure the down-converted signals.
- 3.Near-field optical microscopy in the mid-IR & THzN°3
The aim of this short course is to provide a comprehensive introduction to a microscopy technique allowing nanometric resolution in the MIR and THz range : the scattering scanning probe near-field microscopy (s-SNOM). The basic principle, the experimental setups and the current state of the art will presented. Examples of applications to extract material parameters and to visualize fascinating phenomena like phonons will be also presented.
The participants will have the possibility to use a MIR s-SNOM setup to image graphene samples and interpret the images.
- 4. Magneto-optics & nonreciprocal devices from the mid-IR down to mm-wavesN°4
The aim of this short course is to present the current state-of-the-art of nonreciprocal phenomena for a wide frequency range from the mid-IR down to mm-waves. This course will start from the theoretical concepts mastering Lorentz reciprocity in Maxwell’s equations, and gradually introduce the different concepts to break this fundamental symmetry. Several practical design approaches for THz and MIR one-directionl devices based on magnetooptics will be presented with a special focus on two novel designs for magnetoplasmonic one-directionl mirror isolators operating at 300GHz and 1THz.
The participants to this short course will be able to handle a custom-built magnetooptic THz time-domain spectroscopy setup and if time permits, a quasioptical, VNA-based nonreciprocal S-parameter setup.
- 5. THz communications: antennas and data-links in the 300 GHz bandN°5
The aim of this short course is to present THz communications, from basic devices to the system level. The concepts of a THz communication system will be given on generation, modulation, beam control/handling, detection (direct or sub-harmonic mixing, analysis), with special focus on the use of optically-driven sources as THz transmitters. An overview of the actual challenges in the topic will be presented and discussed. Analysis of link budgets in the 300 GHz range will be proposed.
The participants will be able to handle 300 GHz antenna gain measurements, antenna patterns, detector sensitivity using Schottky diodes. They will also evaluate the performance of a data link with 20 Gbit/s in the 300 GHz range by eye patterns measurements using wideband oscilloscopes and real-time BER (Bit error rate) measurements.
- 6. Fourier-transform characterization of antenna-based mid-IR detectorsN°6
The aim of this short course is to make an introduction to an experimental technique (Fourier-Tranform Spectrometry) and to use it to characterize a fascinating electromagnetic object: an antenna-based mid-IR detector. The double-metal patch antenna structure is able to both confine photons in a highly subwavelength volume and gather radiation from a very large cross section. The focus will go on the recent application of double-metal patch antenna resonators in the THz and mid-IR spectral regions, where they have allowed a substantial increase in the temperature performance of quantum detectors.
The participants will perform reflectivity measurements on patch antenna arrays using a Fourier transform IR (FTIR) spectrometer, and if time permits, photocurrent measurements.