Continuous-wave coherent imaging with terahertz quantum cascade lasers using electro-optic harmonic sampling

Marco Ravaro (1) , Vishal Jagtap (1) , Giorgio Santarelli (2) , Carlo Sirtori (1) , Lianhe Li (3) , S.P. Khanna (3) , Edmund H. Linfield (3) , Stefano Barbieri (1)

1 MPQ (UMR_7162) - Laboratoire Matériaux et Phénomènes Quantiques
2 lp2n-06,lp2n-14
3 School of Electronics and Electrical Engineering

We demonstrate a coherent imaging system based on a terahertz (THz) frequency quantum cascade laser (QCL) phase-locked to a near-infrared fs-laser comb. The phase locking enables coherent electro-optic sampling of the continuous-wave radiation emitted by the QCL through the generation of a heterodyne beat-note signal. We use this beat-note signal to demonstrate raster scan coherent imaging using a QCL emitting at 2.5 THz. At this frequency the detection noise floor of our system is of 3 pW/Hz and the long-term phase stability is <3°/h, limited by the mechanical stability of the apparatus.

Mots clés: quantum cascade laser; terahertz; imaging

Domaines: Optique [physics.optics]

Marco Ravaro, Vishal Jagtap, Giorgio Santarelli, Carlo Sirtori, Lianhe Li, et al.. Continuous-wave coherent imaging with terahertz quantum cascade lasers using electro-optic harmonic sampling. Applied Physics Letters, 2013, 102, pp.091107. ⟨10.1063/1.4793424⟩. ⟨hal-00809317⟩