Stuttgart 2012 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 54: Poster 3
Q 54.55: Poster
Donnerstag, 15. März 2012, 16:30–19:00, Poster.I+II
Towards highly efficient whispering gallery supported THz detection — •Florian Sedlmeir1,2, Dmitry V. Strekalov3, Sebastian Bauerschmidt1,2, Sascha Preu2, Stefan Malzer2, Gottfried H. Döhler1, Harald G. L. Schwefel1,2, and Gerd Leuchs1,2 — 1Max Planck Institut für die Physik des Lichts, Erlangen, Deutschland — 2Universität Erlangen-Nürnberg, Erlangen, Deutschland — 3Jet Propulsion Laboratory, Pasadena, CA, United States
Efficient detection of weak terahertz signals is a very challenging task. Here we present a new concept and first experimental results of measuring weak terahertz signals using a triply-resonant, phase-matched whispering gallery mode resonator (WGMR). The idea is based on sum-frequency generation in a highly nonlinear χ(2)-material (LiTaO3). There, a THz signal and a near infrared pump beam is converted into a near infrared idler beam, which can easily be detected. In order to increase the conversion efficiency the crystal is shaped with a diamond turning machine into a WGMR, where long interactions lengths are possible.
We will present efficient coupling of near infrared light into high quality (Q) modes with Q∼ 108, as well as sufficient Q∼ 200 in the THz domain. Due to the extremely high refractive index nTHz∼6, highly efficient coupling into the WGMR in the THz domain is challenging and novel methods ranging from high index waveguides to grating enhanced evanescent coupling will be discussed. First steps towards measuring the near infrared sidebands will be presented.