Abstract
We present an experimental and theoretical comparison of two different scattering-type scanning near-field optical microscopy (s-SNOM) based techniques in the terahertz regime; nanoscale reflection-type terahertz time-domain spectroscopy (THz nanoscopy) and nanoscale laser terahertz emission microscopy, or laser terahertz emission nanoscopy (LTEN). We show that complementary information regarding a material's charge carriers can be gained from these techniques when employed back-to-back. For the specific case of THz nanoscopy and LTEN imaging performed on a lightly p-doped InAs sample, we were able to record waveforms with detector signal components demodulated up to the 6th and the 10th harmonic of the tip oscillation frequency, and measure a THz near-field confinement down to 11 nm. A computational approach for determining the spatial confinement of the enhanced electric field in the near-field region of the conductive probe is presented, which manifests an effective "tip sharpening" in the case of nanoscale LTEN due to the alternative geometry and optical nonlinearity of the THz generation mechanism. Finally, we demonstrate the utility of the finite dipole model (FDM) in predicting the broadband scattered THz electric field,...Continue Reading
References
Nov 1, 2003·Optics Letters·Toshihiko KiwaKodo Kawase
Dec 15, 2007·Science·M M QazilbashD N Basov
Jun 11, 2008·Optics Express·H-G von RibbeckF Keilmann
Oct 8, 2008·Nano Letters·A J HuberR Hillenbrand
Jul 9, 2007·Optics Express·A CvitkovicR Hillenbrand
Oct 15, 1989·Optics Letters·M ExterD Grischkowsky
Jul 1, 2010·Optics Express·Hui ZhanDaniel M Mittleman
Jun 23, 2012·Nature·Jianing ChenFrank H L Koppens
Apr 27, 2013·Nanotechnology·Hannah J JoyceMichael B Johnston
Oct 15, 2013·Nature Nanotechnology·Z FeiD N Basov
May 2, 2013·The Journal of Physical Chemistry Letters·Alexander A GovyadinovRainer Hillenbrand
Nov 1, 2016·Nature Nanotechnology·Pablo Alonso-GonzálezRainer Hillenbrand
Dec 13, 2016·Nature Nanotechnology·Markus A HuberRupert Huber
May 13, 2017·Scientific Reports·Filchito Renee BagsicanIwao Kawayama
May 3, 2018·Optics Express·Daniel M Mittleman
Apr 2, 2019·Advanced Materials·Xinzhong ChenMengkun Liu
Sep 13, 2019·Optics Express·Neda Alsadat AghamiriYohannes Abate