Electrical Tuning of the Fifth‐Order Optical Nonlinearity of Antimony‐Doped Tin Oxide

Abstract

In this work, the electrical tuning of the fifth‐order nonlinear absorption of antimony‐doped tin oxide (ATO) by ionic liquid gating is demonstrated. The pristine ATO film exhibits two‐photon‐induced excited‐state absorption (2PA‐ESA) with laser excitation at 1030 nm. The fifth‐order nonlinear absorption coefficient (γeff) of the ATO film can be monotonically modified in the range of 0.51 to 3.46 cm3 GW−2 by varying the sample bias, with a maximum enhancement factor of 6.8. The fundamental processes occurring during electrical tuning are revealed. The electrostatic and electrochemical capacitance is responsible for the modification in the number of free carriers in the conduction band of ATO. The electrical modulation of the nonlinear absorption of the ATO is ascribed to the voltage‐dependent diameter of the undepleted core of ATO. A smaller voltage results in the charging of ATO and a larger undepleted core, and consequently the size of the active component for 2PA‐ESA is larger. The electrochemical capacitance results from the chemisorption of H+ and OH− on the surface of the ATO, the larger water content in the ionic liquid affording a larger modulation range for the number of free carriers and the γeff.

Enhanced nonlinear optical performance of perovskite films passivated by porphyrin derivatives

“…The measurement details of the Z-scan technique are referred to from previously reported literature. 18,39,68 The cross-section thicknesses of all films were measured by SEM (Fig. 2f and Fig.…”

Defect-Dependent Nonlinear Absorption in the Lead-Free Double-Perovskite Cs2AgBiBr6

“…The results are shown in Figure a for laser excitation at 515 nm and Figure b for laser excitation at 800 nm. In principle, a slope of n from a ln­( E pulse ) vs ln­(1 – T 0 ) plot corresponds to a nominal ( n + 1) photon absorption. , The slope is 0.54 for Cs 2 AgBiBr 6 with 515 nm laser excitation, suggesting that the NLO process is a combination of one-photon absorption (1PA) and 2PA. In contrast, excitation at 800 nm resulted in a slope of 1.54, indicating that 2PA and three-photon absorption (3PA) occur during NLO absorption.…”

“…To determine the β eff of samples, Z -scan traces were fitted using the following equations: T NL false( z false) = ∑ m = 0 ∞ [ − q 0 false( z false) ] m ( m + 1 ) 3 / 2 q 0 false( z false) = β eff I 0 L eff 1 + true( z z 0 true) 2 L eff = 1 − e − α 0 L α 0 where z is the sample coordinate, I 0 is the on-axis irradiance at the focus, z 0 is the diffraction length of the laser beam, α 0 is the linear absorption coefficient of the sample, and L is the thickness of the samples. For processes containing the third- and fifth-order optical nonlinearity, the γ eff values corresponding to different measurement conditions were extracted from the Z-scan curves …”

“…72 ■ ASSOCIATED CONTENT * sı Supporting InformationChi Zhang − School of Chemical Science and Engineering, Tongji University, Shanghai 200092, P. R. China; orcid.org/0000-0002-5237-8916; Email: chizhang@ tongji.edu.cn Zhipeng Huang − School of Chemical Science and Engineering, Tongji University, Shanghai 200092, P. R. China; orcid.org/0000-0002-7113-2903; Email: zphuang@tongji.edu.cn…”

Phthalocyanine‐Based 2D Polymer for Ultrafast Nonlinear Optical Application

“…[10][11][12][13][14][15][16] Unfortunately, their inherent drawbacks, such as limited degree of conjugation, relatively narrow optical absorption band and poor two-photon absorption (or excitedstate absorption) effect, make it difficult for them to exhibit strong ultrafast (irradiated by incident laser with ultrashort pulse width in the picosecond (ps, 10 −12 s) or even femtosecond (fs, 10 −15 s) range RSA effects in near-infrared (NIR) regions, also their poor solubility in most organic solvents hinders their further processing. [17][18][19][20][21][22][23] Therefore, the development of a new material with remarkable ultrafast RSA performance in NIR regions and favorable solution processability is of great academic interest. 2D materials, such as graphene, MXene (Ti 3 C 2 T X ), molybdenum disulfide (MoS 2 ) and black phosphorus (BP), featured by significant optics characteristics including strong excitonic effects, [24][25][26][27] ultrafast and broadband optical response, [28][29][30] have been demonstrated attractive properties in NLO applications.…”