Apertureless near-field terahertz imaging using the self-mixing effect in a quantum cascade laser

We report two-dimensional apertureless near-field terahertz (THz) imaging using a quantum cascade laser(QCL)source and a scattering probe. A near-field enhancement of the scattered field amplitude is observed for small tip-sample separations, allowing image resolutions of ∼1 μm (∼λ/100) and ∼7 μm to be achieved along orthogonal directions on the sample surface. This represents the highest resolution demonstrated to date with a THz QCL. By employing a detection scheme based on self-mixing interferometry, our approach offers experimental simplicity by removing the need for an external detector and also provides sensitivity to the phase of the reinjected field.

[1]  J. Aizpurua,et al.  Terahertz near-field nanoscopy of mobile carriers in single semiconductor nanodevices. , 2008, Nano letters.

[2]  David A. Ritchie,et al.  THz and sub‐THz quantum cascade lasers , 2009 .

[3]  Peter Uhd Jepsen,et al.  Bendable, low-loss Topas fibers for the terahertz frequency range. , 2009, Optics express.

[4]  F. Keilmann,et al.  Near-field probing of vibrational absorption for chemical microscopy , 1999, Nature.

[5]  C. Boccara,et al.  THz emission microscopy with sub-wavelength broadband source. , 2008, Optics express.

[6]  R. Kersting,et al.  Terahertz microscopy of charge carriers in semiconductors , 2006 .

[7]  Edmund H. Linfield,et al.  Coherent three-dimensional terahertz imaging through self-mixing in a quantum cascade laser , 2013 .

[8]  Fritz Keilmann,et al.  Enhanced dielectric contrast in scattering-type scanning near-field optical microscopy , 2000 .

[9]  Martin Koch,et al.  THz near-field imaging , 1998 .

[10]  F. Keilmann,et al.  Complex optical constants on a subwavelength scale. , 2000, Physical review letters.

[11]  H. Beere,et al.  Research data supporting "Fast terahertz imaging using a quantum cascade amplifier" , 2015 .

[12]  Edmund H. Linfield,et al.  Terahertz quantum cascade lasers with >1 W output powers , 2014 .

[13]  Igal Brener,et al.  Terahertz near-field microscopy based on a collection mode detector , 2000 .

[14]  R. Kersting,et al.  Terahertz imaging with nanometer resolution , 2003 .

[15]  Hanspeter Helm,et al.  Terahertz near-field imaging of electric and magnetic resonances of a planar metamaterial. , 2009, Optics express.

[16]  James A. Harrington,et al.  Waveguide mode imaging and dispersion analysis with terahertz near-field microscopy , 2009 .

[17]  Qing Hu,et al.  Ground state terahertz quantum cascade lasers , 2012 .

[18]  J. M. Chamberlain,et al.  Terahertz near-field imaging using subwavelength plasmonic apertures and a quantum cascade laser source. , 2011, Optics letters.

[19]  Edmund H. Linfield,et al.  2.9THz quantum cascade lasers operating up to 70K in continuous wave , 2004 .

[20]  Yah Leng Lim,et al.  Terahertz imaging through self-mixing in a quantum cascade laser. , 2011, Optics letters.

[21]  Hongkyu Park,et al.  Subsurface nanoimaging by broadband terahertz pulse near-field microscopy. , 2015, Nano letters.

[22]  G. Scalari,et al.  Quantum cascade lasers: 20 years of challenges. , 2015, Optics express.

[23]  Koji Ishibashi,et al.  An on-chip near-field terahertz probe and detector , 2008 .

[24]  D. Mittleman,et al.  A study of background signals in terahertz apertureless near-field microscopy and their use for scattering-probe imaging , 2009 .

[25]  J. W. Lee,et al.  Fourier-transform terahertz near-field imaging of one-dimensional slit arrays: mapping of electric-field-, magnetic-field-, and Poynting vectors. , 2007, Optics express.

[26]  Andreas Bitzer,et al.  Terahertz near-field imaging of metallic subwavelength holes and hole arrays , 2008 .

[27]  Christoph Lienau,et al.  Apertureless near-field optical microscopy: Tip–sample coupling in elastic light scattering , 2003 .

[28]  Aurèle J. L. Adam,et al.  Review of Near-Field Terahertz Measurement Methods and Their Applications , 2011 .

[29]  Oleg Mitrofanov,et al.  Near-field microscope probe for far infrared time domain measurements , 2000 .

[30]  A. Taylor,et al.  Surface plasmons in terahertz metamaterials. , 2008, Optics express.

[31]  H. Beere,et al.  Differential near-field scanning optical microscopy with THz quantum cascade laser sources. , 2009, Optics express.

[32]  Yuh-Jing Hwang,et al.  All-terahertz fiber-scanning near-field microscopy. , 2009, Optics letters.

[33]  D. W. van der Weide,et al.  Spectroscopic THz near-field microscope. , 2008, Optics express.

[34]  Cyril C. Renaud,et al.  Imaging and Analysis of THz Surface Plasmon Polariton Waves with the Integrated Sub-wavelength Aperture Probe , 2011 .