Optical frequency combs (FCs), that establish a rigid phase-coherent link between the microwave and optical domains of the electromagnetic spectrum, are emerging as a key high-precision tools for the development of quantum technology platforms. These include potential applications for communication, computation, information, sensing and metrology, and can extend from the near-infrared with...
We present optical beatnote detection from a THz
QCL comb operating at 80 K by direct free space mixing in a high-frequency Hot Electron Bolometer
Terahertz (THz) radiation exhibits properties of great interest and potential applications in several scientific fields. For example, THz waves (in the spectral range between 0.1 and 30 THz) find direct applications in spectroscopy of innovative materials, time-domain quantum optics, and biological sensing [1]. However, THz science remains challenging because of the lack of suitable sources...
THz radiation, in the region between 0.1 and 10 THz, has attracted a lot of interest in the last years due to its peculiar interaction properties with matter and the possibility of applying it both in telecommunications and sensing devices [1]. One of the current subjects of active investigation in this field is the enhancement and optimization of the interaction between THz radiation and...
Surface plasmons, the collective oscillations of electrons in metals and doped semiconductors, show outstanding electromagnetic (EM) properties spanning from a reduced wavelength in comparison to that of an exciting electromagnetic field, an extreme electric field enhancement several orders of magnitude larger than the incident field, to several nonlinear effects like harmonic generation and...
Quantum materials and terahertz radiation present a mutual interplay. On one hand, linear terahertz spectroscopy allows to study the unconventional excitations of quantum materials and nonlinear and time-resolved spectroscopy their temporal evolution. On the other hand, quantum materials can be used to produce and manipulate terahertz radiation, opening up the possibility of developing new...
An accurate retrieval procedure has been developed in order to extract both the dielectric and magnetic response of thin and thick samples in the THz band. Differently from a previous approach [1], the exact expressions of the complex reflection $\tilde{R}$ and transmission $\tilde{T}$ of the THz beam normally impinging on the sample surface are used. The core of the methodology consists in...
Terahertz (THz) generation by two-color plasma has garnered attention for its capacity of providing intense and ultra-broadband THz pulses. Like any form of electromagnetic radiation, controlling wave polarization is crucial for a wide range of applications [1]. However, accurately characterizing and selectively controlling the polarization of broadband THz pulses remains challenging due to...
In this presentation, I will discuss the use of THz ultrafast spectroscopy to investigate extended systems. Optical Pump – THz Probe spectroscopy (OPTPs) has been extensively used to investigate the carrier and lattice ultrafast dynamics in bulk and low-dimensional semiconductors and topological matter [1-5]. Free carriers, electron-phonon related phenomena, and low-energy collective...
The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the ultrafast dynamical control and creation of novel ordered states of matter, not accessible in thermodynamic equilibrium, is receiving much attention. Among those, the theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of...
Plastic foams are widely used materials made by mixing polymers with a gas [1]. Their mechanical and physical properties are governed mainly by the density, so it is important to assess this feature to check the accuracy of the production process. However, while simple in principle, density measurements are not straightforward in practice, especially when objects have a non-uniform density....
In recent years, hazelnut cultivation is becoming increasingly important in terms of areas invested and crops
expected. Among the various quality defects, one of the most detrimental alterations to hazelnut quality is “cimiciato”
defect, which is caused by a group of insects belonging to the families of Coreidae and Pentatomidae. Nowadays no
reliable automatic method to discriminate between...
We report on the development of novel optical components based on metamaterials, carried out in the last years, for mm and sub-mm astronomical instrumentation. Using the mesh-filter technology, we have realised transmissive and reflective half-wave plates, flat lenses, anti-reflection coatings, absorbers, etc. The metal-mesh technology, based on copper grids embedded within polypropylene...
Nowadays, Teraherz (THz) waves are receiving huge attention in the frame of cultural heritage [1], [2]. THz imaging and spectroscopy are, indeed, useful tools for gathering high-resolution (of the order of mm) information about construction modality, preparing drawings and author’s re-paintings, conservation state of artworks as well as to identify previous restoration actions, mainly of...
The abstract is in attachment
We report a study at a mesoscopic level on the THz dynamics of three aliphatic alcohols (2-propanol, methanol, and ethanol), one diol (ethylene glycol), and the corresponding water solutions at room temperature, using a time domain ellipsometer. The dielectric response of the pure liquids is nicely fitted using a generalized Debye-Lorentz model, which considers hydrogen-bond rupture and...
The THz spectrum offers the potential of a plethora of applications, ranging from the imaging through non transparent media to wireless-over-fiber communications and THz-photonics. The latter framework would greatly benefit from the development of optical-to-THz wavelength converters. Exploiting Difference Frequency Generation in a nonlinear all dielectric nanoantenna, we propose a compact...
Terahertz (THz)-band communications are a key enabler for ultrahigh bandwidth and ultralow latency communication paradigms. When integrated with other THz-band applications, such as localization, sensing, and imaging, THz technologies may lead
to the deployment of intelligent wireless communication systems. However, communications at THz are quite challenging due to the severe attenuation of...
Terahertz/Infrared (THz/IR) radiation and technologies have found incredible development in the last few decades due to their applications in many different fields, ranging from indoor and outdoor communication, security, environmental monitoring, biological research, medical applications and finally as a spectroscopic investigation tool in condensed matter [1]. However, many of these...
Coatings play a crucial role for the functionality of vacuum chambers in particle accelerators, serving dual purposes by efficiently facilitating pumping and mitigating electron cloud effects. However, their impact on the surface resistance of chamber walls raises concerns, potentially influencing machine performances and imposing limitations on achievable energies and currents. Therefore, an...
