Article abstract

Nature Photonics 3, 732 - 737 (2009)
Published online: 22 November 2009 | doi:10.1038/nphoton.2009.218

Subject Categories: Lasers, LEDs and light sources | Terahertz optics

Tuning a terahertz wire laser

Qi Qin1, Benjamin S. Williams1,2, Sushil Kumar1, John L. Reno3 & Qing Hu1

Tunable terahertz lasers are desirable in applications in sensing and spectroscopy because many biochemical species have strong spectral fingerprints at terahertz frequencies. Conventionally, the frequency of a laser is tuned in a similar manner to a stringed musical instrument, in which pitch is varied by changing the length of the string (the longitudinal component of the wave vector) and/or its tension (the refractive index). However, such methods are difficult to implement in terahertz semiconductor lasers because of their poor outcoupling efficiencies. Here, we demonstrate a novel tuning mechanism based on a unique ‘wire laser’ device for which the transverse dimension w is less doubleλ. Placing a movable object close to the wire laser manipulates a large fraction of the waveguided mode propagating outside the cavity, thereby tuning its resonant frequency. Continuous single-mode redshift and blueshift tuning is demonstrated for the same device by using either a dielectric or metallic movable object. In combination, this enables a frequency tuning of ~137 GHz (3.6%) from a single laser device at ~3.8 THz.

  1. Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
  2. Department of Electrical Engineering and California NanoSystems Institute, University of California, Los Angeles, California 90095, USA
  3. Sandia National Laboratories, Department 1123, MS 0601, Albuquerque, New Mexico 87185-0601, USA

Correspondence to: Qing Hu1 e-mail:


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