TY - JOUR
T1 - Perfect absorption by an atomically thin crystal
AU - Horng, Jason
AU - Martin, Eric W.
AU - Chou, Yu Hsun
AU - Courtade, Emmanuel
AU - Chang, Tsu Chi
AU - Hsu, Chu Yuan
AU - Wentzel, Michael Henr
AU - Ruth, Hanna G.
AU - Lu, Tien Chang
AU - Cundiff, Steven T.
AU - Wang, Feng
AU - Deng, Hui
N1 - Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/8
Y1 - 2020/8
N2 - Optical absorption is one of the most fundamental processes in light-matter interactions. The ability to achieve and control high absorption is crucial for a broad range of modern photonic technologies. In nanomaterials of length scales much smaller than a wavelength, optical absorption is typically a weak perturbation. To achieve high absorption, exquisite techniques and structures have been developed, such as coherent interference of multiple laser beams and plasmonic metasurfaces. Here, we show that a robust critical-coupling condition exists to allow perfect absorption of light by a subnanometer-thick two-dimensional semiconductor, when the radiative-decay rate of the exciton resonance balances with its loss rate. We measure an absorption up to 99.6% in a monomolecular MoSe2 crystal placed in front of a flat mirror. We furthermore demonstrate control of the perfect absorption by tuning the exciton-phonon, exciton-exciton, and exciton-photon interactions with temperature, pulsed laser excitation, and a movable mirror, respectively. Our work suggests a mechanism to achieve and control critical coupling in two-dimensional excitonic systems, enabling photonic applications including ultrafast low-power light modulators and sensitive optical sensing.
AB - Optical absorption is one of the most fundamental processes in light-matter interactions. The ability to achieve and control high absorption is crucial for a broad range of modern photonic technologies. In nanomaterials of length scales much smaller than a wavelength, optical absorption is typically a weak perturbation. To achieve high absorption, exquisite techniques and structures have been developed, such as coherent interference of multiple laser beams and plasmonic metasurfaces. Here, we show that a robust critical-coupling condition exists to allow perfect absorption of light by a subnanometer-thick two-dimensional semiconductor, when the radiative-decay rate of the exciton resonance balances with its loss rate. We measure an absorption up to 99.6% in a monomolecular MoSe2 crystal placed in front of a flat mirror. We furthermore demonstrate control of the perfect absorption by tuning the exciton-phonon, exciton-exciton, and exciton-photon interactions with temperature, pulsed laser excitation, and a movable mirror, respectively. Our work suggests a mechanism to achieve and control critical coupling in two-dimensional excitonic systems, enabling photonic applications including ultrafast low-power light modulators and sensitive optical sensing.
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U2 - 10.1103/PhysRevApplied.14.024009
DO - 10.1103/PhysRevApplied.14.024009
M3 - Article
AN - SCOPUS:85092003876
SN - 2331-7019
VL - 14
JO - Physical Review Applied
JF - Physical Review Applied
IS - 2
M1 - 024009
ER -