Abstract-µJ-level multi-cycle terahertz generation in a periodically poled Rb:KTP crystal

 

Wenlong Tian, Giovanni Cirmi, Halil T. Olgun, Patrick Mutter, Carlota Canalias, Andrius Zukauskas, Lu Wang, Elias Kueny, Frederike Ahr, Anne-Laure Calendron, Fabian Reichert, Kore Hasse, Yi Hua, Damian N. Schimpf, Hüseyin Çankaya, Mikhail Pergament, Michael Hemmer, Nicholas Matlis, Valdas Pasiskevicius, Fredrik Laurell, Franz X. Kärtner

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-46-4-741

We demonstrate multi-cycle terahertz (MC-THz) generation in a 15.5 mm long periodically poled rubidium (Rb)-doped potassium titanyl phosphate (Rb:PPKTP) crystal with a poling period of 300 µm. By cryogenically cooling the crystal to 77 K, up to 0.72 µJ terahertz energy is obtained at a frequency of 0.5 THz with a 3 GHz bandwidth. A maximum internal optical-to-terahertz conversion efficiency of 0.16% is achieved, which is comparable with results achieved using periodically poled lithium niobate crystal. Neither photorefractive effects nor damage was observed with up to 900mJ/cm2$900{\mathrm{m}\mathrm{J}/\mathrm{c}\mathrm{m}}^2$, showing the great potential of Rb:PPKTP for multi-millijoule-level MC-THz generation.

© 2021 Optical Society of America

NATO launches first scientific cooperation initiative with Algeria

For the first time, the NATO Science for Peace and Security (SPS) Programme is supporting a multi-year research project with Algeria. The new activity will develop an innovative detection system to help in the fight against terrorism while engaging key partners in practical cooperation.

https://www.nato.int/cps/en/natohq/news_148023.htm

Experts involved in the SPS project “Implementation of a Terahertz Imaging and Detection System” gathered at NATO Headquarters to kick off the innovative scientific project between NATO and Algeria

Kicked off at NATO Headquarters on 26 October 2017, the new project brings together the Université Savoie Mont Blanc (France), Ecole Militaire Polytechnique (Algeria) and KTH Royal Institute of Technology (Sweden) to work on the design and development of a terahertz (THz) imaging and detection system. This new system will be able to detect hazardous objects like concealed weapons or explosives and will help to secure vulnerable places from terrorist threats, such as airports, railway stations, critical infrastructure as well as government buildings.

“THz frequency range is a scientific field that has seen rapid technological advances and growth in interest for its potential application in a number of domains, ranging from security, imaging, detection, and product inspection to chemical spectroscopy, astronomy, telecommunication, material characterisation and medical applications,” said Professor Jean-Louis Coutaz from Université Savoie Mont Blanc, which is leading this research initiative.

The kick-off meeting marked the start of the project which will strengthen ties between NATO, France and two partner countries, Algeria and Sweden, through practical cooperation. By providing cutting-edge technological solutions in support of the fight against terrorism, this SPS project is also contributing to NATO’s wider efforts to project stability beyond Alliance borders. It also represents an important milestone in NATO’s engagement with partners in the south. “By building expert networks, north to south, this activity will help to develop scientific skills and technology to counter emerging threats,” said Professor Fredrik Laurell from Sweden.

The new system is to be installed at the Ecole Militaire Polytechnique of Bordj El Barhri, Algeria. In the long run, this experimental set-up will provide an important basis for further scientific research in this field in Algeria. “This SPS project, for the first time, will provide terahertz imaging capabilities for Algeria. This will enable scientific research in this field, fostering a generation of young scientists from Algeria,” said Dr Deniz Beten, Senior SPS and Partnership Cooperation Advisor. Dr Mohamed Lazoul, from Ecole Militaire Polytechniqueand SPS Project Co-Director, stated that “the system will improve the capability of our institution in this cutting-edge technology and will allow significant sharing of expertise and know-how in the field of terahertz imaging detection, that will be a key technology in support of the fight against terrorism in the years to come.”

NATO’s SPS Programme is supporting practical cooperation between the Alliance and partner countries in civil science, technology, innovation and knowledge exchange.

Abstract-All-dielectric KTiOPO4 metasurfaces based on multipolar resonances in the terahertz region

Jingyi Tian, Yuanqing Yang, Min Qiu, Fredrik Laurell, Valdas Pasiskevicius, and Hoon Jang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-20-24068

We employ ferroelectrics to study the multipolar scattering in all-dielectric metasurfaces based on KTiOPO4 (KTP) micro-disks for efficient manipulation of electromagnetic waves in the THz spectral region (0.6-1.5 THz). By adjusting the aspect ratio of the disks near the multipolar resonances, we show that the KTP disk array can form a multifunctional metasurface that covers the entire range of the electromagnetic response with resonantly enhanced anisotropic properties. The proposed ferroelectric metasurfaces will provide a versatile platform to manipulate THz waves, and open possibilities to monolithically combine it with THz generation.

© 2017 Optical Society of America

Abstract-Terahertz parametric generation and amplification from potassium titanyl phosphate in comparison with lithium niobate and lithium tantalate

Ming-Hsiung Wu, Yu-Chung Chiu, Tsong-Dong Wang, Gang Zhao, Andrius Zukauskas, Fredrik Laurell, and Yen-Chieh Huang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-23-25964

We report superior terahertz parametric generation from potassium titanyl phosphate (KTP) over congruent-grown lithium niobate (CLN) and lithium tantalate (CLT) in terms of parametric gain and laser damage resistance. Under the same pump and crystal configurations, the signal emerged first from KTP, 5% Mg-doped CLN, CLN, and then finally from CLT. The signal growth rate in KTP was comparable to that in 5%-Mg-doped CLN, but the signal power from KTP reached a much higher value after all the other crystals were damaged by the pump laser. We further demonstrate seeded terahertz parametric amplification in an edge-cut KTP at 5.74 THz. The THz parametric amplifier (TPA) employs a 17-mm long KTP gain crystal, pumped by a passively Q-switched pump laser at 1064 nm and seeded by a continuous-wave diode laser tuned to the signal wavelength at 1086.2 nm. With 5.8-mJ energy in a 520-ps pump pulse and 100-mW seed signal power, we measured 5-W peak-power THz output from the KTP TPA with 22% pump depletion. In comparison, we measured no detectable THz output power from a similar edge-cut CLN TPA under the same pump power, detection scheme, and crystal configuration, when tuning the seed laser wavelength to 1072.2 nm and attempting to generate a radiation at 2.1 THz.

© 2016 Optical Society of America

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