Three-dimensional imaging with a terahertz quantum cascade laser

Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser.

We demonstrate coherent three-dimensional terahertz imaging by frequency modulation of a quantum cascade laser in a compact and experimentally simple self-mixing scheme. Through this approach, we can realize significantly faster acquisition rates compared to previous schemes employing longitudinal mechanical scanning of a sample. We achieve a depth resolution of better than 0.1 μm with a power ...

Local Reconstruction for Three Dimensional Terahertz Imaging Using a CW Quantum Cascade Laser

This paper reports on the local reconstruction of a region-of-interest from 3D terahertz imaging data obtained via a quantum cascade laser (QCL). It is an important step in understanding the trade-off between wavelet based techniques and traditional filtered back projection (FBP) for local reconstruction of terahertz images. The advantage of local reconstruction is a reduction in measurement ti...

Coherent three-dimensional terahertz imaging through self-mixing in a quantum cascade laser

High-spectral-resolution terahertz imaging with a quantum-cascade laser.

We report on a high-spectral-resolution terahertz imaging system operating with a multi-mode quantum-cascade laser (QCL), a fast scanning mirror, and a sensitive Ge:Ga detector. By tuning the frequency of the QCL, several spectra can be recorded in 1.5 s during the scan through a gas cell filled with methanol (CH3OH). These experiments yield information about the local absorption and...

Terahertz imaging through self-mixing in a quantum cascade laser.

We demonstrate terahertz (THz) frequency imaging using a single quantum cascade laser (QCL) device for both generation and sensing of THz radiation. Detection is achieved by utilizing the effect of self-mixing in the THz QCL, and, specifically, by monitoring perturbations to the voltage across the QCL, induced by light reflected from an external object back into the laser cavity. Self-mixing im...