Share Email Print
cover

Proceedings Paper

Continuous wave terahertz emitter arrays for spectroscopy and imaging applications
Author(s): S. Bauerschmidt; S. Preu; S. Malzer; G. H. Döhler; L. J. Wang; H. Lu; A. C. Gossard
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

We report on arrays of THz-emitters based on n-i-pn-i-p-superlattice photomixers for imaging and spectroscopic applications. The output power of a n-i-pn-i-p superlattice photomixers recently has reached nearly 1 μW at 1 THz with a broadband antenna. There are no fundamental physical limitations at this stage for further improvement. Tunable continuous wave (CW) THz-sources for imaging and spectroscopy are highly desired tools for security and environmental applications. In particular, most stand-off imaging applications require a rather high THz power to allow for a sufficient dynamic range, and a narrow illumination spot size for high spatial resolution. Both goals can be reached by using an array of mutually coherent photomixers. We have simulated beam patterns for an arbitrary number of mutually coherent single sources with respect to a small beam size and high peak intensity. Here, we confirm the simulations experimentally by an array of 4 sources with a 4 inch THz optics. The beam profile is measured in the target plane at a stand-off distance of 4.2 m. As a result, the beam diameter is reduced by a factor of 6 and the peak intensity is enhanced by a factor of close to (4)2 = 16, in excellent agreement with our simulations. Such an arrangement allows not only for high resolution stand-off imaging but also for spectroscopic investigations at stand-off distances. The THz frequency can be tuned over more than a decade (i.e. 0.1 to 2.5 THz) by tuning the wavelength of the mixing lasers. The spectral linewidth of the THz sources is only limited by the linewidths of the mixing lasers and can be made extremely narrow. A straightforward demonstration is achieved by water vapor spectroscopy in laboratory air with a single source.

Paper Details

Date Published: 27 April 2010
PDF: 11 pages
Proc. SPIE 7671, Terahertz Physics, Devices, and Systems IV: Advanced Applications in Industry and Defense, 76710D (27 April 2010); doi: 10.1117/12.850090
Show Author Affiliations
S. Bauerschmidt, Max-Planck Institute for the Science of Light (Germany)
S. Preu, Max-Planck Institute for the Science of Light (Germany)
S. Malzer, Max-Planck Institute for the Science of Light (Germany)
G. H. Döhler, Max-Planck Institute for the Science of Light (Germany)
L. J. Wang, Max-Planck Institute for the Science of Light (Germany)
H. Lu, Univ. of California, Santa Barbara (United States)
A. C. Gossard, Univ. of California, Santa Barbara (United States)


Published in SPIE Proceedings Vol. 7671:
Terahertz Physics, Devices, and Systems IV: Advanced Applications in Industry and Defense
Mehdi Anwar; Nibir K. Dhar; Thomas W. Crowe, Editor(s)

© SPIE. Terms of Use
Back to Top