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Switching the Nonparametric Optical Nonlinearity of Tungsten Oxide by Electrical Modulation
Author(s) -
Li Hui,
Hou Ruipeng,
Sun Yanhui,
Diao Mengjuan,
Liang Ying,
Chen Xin,
Huang Zhipeng,
Wang Jun,
Humphrey Mark G.,
Yu Zhiyang,
Zhang Chi
Publication year - 2021
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202002188
Subject(s) - materials science , saturable absorption , two photon absorption , absorption (acoustics) , optoelectronics , graphene , doping , oxide , modulation (music) , tungsten , wavelength , molecular physics , laser , optics , nanotechnology , physics , fiber laser , acoustics , metallurgy , composite material
Abstract This work shows the electrical switching of the nonparametric optical nonlinearity of tungsten oxide (WO 3− x ). The sign and magnitude of the effective nonlinear absorption coefficient (β eff ) can be modulated via application of an external bias. With laser excitation at 1030 nm, WO 3− x shows a relatively large saturable absorption (SA) under an applied voltage ( V A ) of − 2.5 V, with β eff being as large as −632 cm GW −1 , while reverse saturable absorption (RSA) is found for V A larger than −1.5 V. The electrical switching of the nonlinear optical (NLO) response is reproducible and durable. Both electrostatic and electrochemical dopings of WO 3− x occur during V A variation, with SA resulting mainly from the electrochemical doping (the intercalation of H + into the lattice of WO 3− x ). The wavelength‐dependent NLO performance of pristine WO 3− x is attributed to competition between one‐photon absorption and two‐photon absorption, while the V A ‐derived NLO response is correlated with variation in the band structure and its population. These results suggest a promising approach for the postsynthesis modulation of the NLO response and a potential device configuration for further optoelectric applications.