µJ-level multi-cycle terahertz generation in a periodically poled Rb:KTP crystal
Wenlong Tian, Giovanni Cirmi, H. T. Olgun, Patrick Mutter, Carlota Canalias, Andrius Žukauskas, Lu Wang, Emma Kueny, Frederike Ahr, Anne-Laure Calendron, Fabian Reichert, Kore Hasse, Yi Hua, Damian N. Schimpf, Hüseyin Çankaya, Mikhail Pergament, M. Hemmer, Nicholas H. Matlis, Valdas Pašiškevičius, Fredrik Laurell, Franz X. Kärtner
Abstract
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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>900</mml:mn> </mml:mrow> <mml:mspace width="thickmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">m</mml:mi> <mml:mi mathvariant="normal">J</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> , showing the great potential of Rb:PPKTP for multi-millijoule-level MC-THz generation.