An innovative laser, capable of emitting a very focused beam has been obtained thanks to the double nature of the Terahertz waves. The study, published in Light: Science & Applications, was carried out by a group of researchers from CNR NANO - the Nanoscience Institute of the National Research Council and the University of Pisa, in collaboration with SNS - Scuola Normale Superiore and the University of Cambridge.
Terahertz waves, which easily penetrate plastic, textiles and other materials, are the new frontier in radiology applied to the detection of hidden weapons or bio-agents, or defects in materials, packaging materials or artwork.
Terahertz waves are electromagnetic waves “in between” microwaves and infrared light and have a hybrid nature: they propagate with the properties of waves – like radio waves – and with those of light. That is why they can be manipulated, combining the techniques of these two fields, using both antennas and lenses or mirrors.
This is what was done in the new laser by Luca Masini, Alessandro Pitanti, Lorenzo Baldacci, Miriam Vitiello from CNR NANO, coordinated by Alessandro Tredicucci, University of Pisa, with the aim to generate a highly collimated Terahertz wave beam to overcome the limits of microlasers available today.
"The original idea" – explained Luca Masini from CNR NANO and SNS – "is to use the two natures of Terahertz radiation in one device: that of light and that of microwaves. In fact, to generate the radiation, the device treats it as if it were light, using a disk of artificial material consisting of semiconductor layers, whereas, to propagate it outwards, it manipulates it like a wave, using an embedded gold antenna. The result is a vertical and very focused emission that allows this laser to be used in devices for the spectroscopic analysis of materials and to be integrated into the new miniaturized laboratories, the so-called Labs-On-a-Chip”.
Terahertz waves, considered to be the X-rays of the future for the great potential in imaging applications (from body scanners to poison detection, to the recent water-saving applications), coupled with the low health risks, are the new frontier in photonics.
The laser was developed in the context of the European ERC SouLMan project led by Alessandro Tredicucci, University of Pisa, who said: "Generating Terahertz radiation has been a scientific challenge for many years. Now, the new challenge is to create a technology with increasingly less complex devices. Our laser, which for the first time uses a hybrid approach, goes in this direction as it allows the miniaturization of the device and a reduction of power consumption for its operation."
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