TY  - JOUR
VL  - 19
UR  - https://doi.org/10.1021/acs.nanolett.9b01623
A1  - Mitrofanov, O
EP  - 4626
N2  - Strong coupling of an intersubband (ISB) electron transition in quantum wells to a subwavelength plasmonic nanoantenna can give rise to intriguing quantum phenomena, such as ISB polariton condensation, and enable practical devices including low threshold lasers. However, experimental observation of ISB polaritons in an isolated subwavelength system has not yet been reported. Here, we use scanning probe near-field microscopy and Fourier-transform infrared (FTIR) spectroscopy to detect formation of ISB polariton states in a single nanoantenna. We excite the nanoantenna by a broadband IR pulse and spectrally analyze evanescent fields on the nanoantenna surface. We observe the distinctive splitting of the nanoantenna resonance peak into two polariton modes and two ?-phase steps corresponding to each of the modes. We map ISB polariton dispersion using a set of nanoantennae of different sizes. This nano-FTIR spectroscopy approach opens doors for investigations of ISB polariton physics in the single subwavelength nanoantenna regime.
ID  - discovery10075995
N1  - This version is the author accepted manuscript. For information on re-use, please refer to the publisher?s terms and conditions.
PB  - American Chemical Society
TI  - Observation of Intersubband Polaritons in a Single Nanoantenna Using Nano-FTIR Spectroscopy
Y1  - 2019/07/10/
JF  - Nano Letters
AV  - public
KW  - Intersubband polariton
KW  -  near-field microscopy
KW  -  quantum well
KW  -  nanoantenna
KW  -  nano-FTIR
IS  - 7
SP  - 4620
SN  - 1530-6984
ER  -