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Tuning a Tetrahertz Wire LaserTunable 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 much much less than lambda. 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 approximately equal to 137 GHz (3.6%) from a single laser device at approximately equal to 3.8 THz.
Document ID
20100017264
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Qin, Qi
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Williams, Benjamin S.
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Kumar, Sushil
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Reno, John L.
(Sandia National Labs. Albuquerque, NM, United States)
Hu, Qing
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Date Acquired
August 24, 2013
Publication Date
December 1, 2009
Publication Information
Publication: Nature Photonics
Publisher: Macmillan Publishers Limited
Volume: 3
Subject Category
Lasers And Masers
Funding Number(s)
CONTRACT_GRANT: DE-AC04-94AL85000
CONTRACT_GRANT: NNX07AI99G
Distribution Limits
Public
Copyright
Other

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