Z-scan theory of two-photon absorption saturation and experimental evidence

Gu, Bing; Fan, Ya-Xian; Chen, Jing; Wang, Hui-Tian; He, Jun; Ji, Wei

doi:10.1063/1.2795997

Cited by 72 publications

(50 citation statements)

References 24 publications

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“…Moreover, the material has a larger band gap of 4.05 eV (estimated from the absorption spectrum of TTCS crystal, not shown here) which leads to lowering the value of b. A similar type of variation in b value was observed in semiconducting materials like ZnSe, CdS, CdSe, whose energy gap and b values are 2.67, 2.42, 1.71 eV and 3.0, 6.4, 9.5 cm/GW respectively [22]. Fig.…”

Section: Resultssupporting

confidence: 56%

Two-photon absorption and optical limiting in tristhiourea cadmium sulphate

Dhanuskodi

Girisun

Smijesh

et al. 2010

Chemical Physics Letters

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Section: Resultssupporting

confidence: 56%

Two-photon absorption and optical limiting in tristhiourea cadmium sulphate

Dhanuskodi

Girisun

Smijesh

et al. 2010

Chemical Physics Letters

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“…This finding clearly confirms the dominance of 2PA in the present experiment [3] . In another calculation, using the dispersion scaling rule given by Sheik-Bahae et al, the normalized 2PA maxima (peak) near the wavelength of 355 nm is obtained by taking the bandgap of the material of 5.2 eV (Fig.…”

supporting

confidence: 81%

Observation of enhanced two-photon absorption in ZnS quantum dots at an ultraviolet wavelength

Kumbhakar¹,

Chattopadhyay²,

Sarkar³

et al. 2011

中国光学快报

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Two-photon absorption (2PA) in zinc sulphide (ZnS) and Mn 2+ -doped ZnS quantum dots is reported by the z-scan technique, with nanosecond pulsed laser radiation at 355 nm. The observed values of the 2PA cross section of all the samples are 10 5 times larger than that of bulk ZnS. OCIS codes: 190.0190, 160.4236, 190.4180. doi: 10.3788/COL201109.101902. Researchers have recently expanded their research interests to find highly potential multiphoton active materials [1−10] . Amongst others, zinc sulphide (ZnS) and Mn 2+ -doped ZnS (ZnS:Mn) quantum dots (QDs) have been found to be potential materials because of their visible luminescence and interesting nonlinear optical (NLO) properties [5−8,10−12] . Reports on the multiphoton absorption properties of ZnS QDs have been published previously. For example, two-photon absorption (2PA) has been reported by Zheng et al. with picosecond laser radiation at 532 nm in 0.5% Mn 2+ -doped ZnS QDs [7] . Some enhancements in 2PA have been reported in ZnSe/ZnS core/shell at 806 nm and in ZnS quantum structures at 532-nm laser pulses [13,14] . However, to date, there has been no report on the measurement of NLO properties of ZnS and ZnS:Mn QDs in the ultraviolet (UV) region. In this letter, we present our observation of 2PA in undoped ZnS and ZnS:Mn QDs at an UV wavelength of 355 nm. The obtained values of the 2PA cross section in the studied samples are ∼ 10 5 times larger than that of the available reported value of bulk ZnS [11] . The samples used in this work are freshly prepared through the chemical precipitation method [11] . The synthesized undoped ZnS and 1% and 2.5% Mn 2+ -doped ZnS samples are henceforth denoted as R I , R II , and R III , respectively, unless otherwise specified. The UV-visible absorption characteristics of the samples, as obtained from the measurement in a spectrophotometer (Hitachi U-3010), are shown in Fig. 1. An X-ray diffraction measurement of the samples ensures the average particle size (radius) to be ∼1.5 nm [10] . The experimental z-scan set-up used for the measurement of NLO properties is a standard one [2,8,15] . However, in the present experiment, the excitation source of 355-nm radiation is obtained through a third harmonic generation from a Q-switched Nd:YAG laser (10 ns, 10 Hz repetition rate). To avoid the absorption of the input beam in the lens material itself, a quartz lens with a focal length of 7.5 cm is used to focus the 355-nm radiation. The beam waist (w 0 ) and the confocal parameter (z 0 ) at the focus are 7 and 350 µm, respectively. After they are dispersed in methanol, the as-synthesized nanopowders are kept in a quartz cuvette with a path length (L) of 2 mm for the z-scan measurement, satisfying the thick sample condition (L > n 0 z 0 ) in the present experiment. Here, n 0 is the linear refractive index of the samples at a 355-nm wavelength. In Fig. 1, the values of the linear absorption coefficient (α) of R I , R II , and R III samples are 0.50, 0.33, and 0.47 cm −1 , respectively, at the excitation wavelength of 355 ...

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“…To investigate the saturation intensity (I s ) of the Bi 2 Te x Se 3−x nanosheets, a hyperbolic approach saturation numerically model for semiconductors is used, which is expressed as4041 , where and are the intensity-dependent and low-intensity coefficients, respectively. The best fit is shown in the inset of Fig.…”

Section: Resultsmentioning

confidence: 99%

Ultra-broadband Nonlinear Saturable Absorption for Two-dimensional Bi2TexSe3−x Nanosheets

Wang

Liu

Yuan

et al. 2016

Sci Rep

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We report the ultra-broadband nonlinear optical (NLO) response of Bi2TexSe3−x nanosheets produced by a facile solvothermal method. Our result show that the extracted basic optical nonlinearity parameters of Bi2TexSe3−x nanosheets, αNL, Imχ(3), and FOM reach ~104 cm/GW, ~10−8 esu and ~10−13 esu cm, respectively, which are several orders of magnitude larger than those of bulk dielectrics. We further observed the excitation intensity dependence of the NLO absorption coefficient and the NLO response sensitivity. The mechanisms of those phenomena were proposed based on physical model. The wavelength dependence of the NLO response of Bi2TexSe3−x nanosheets was investigated, and we determined that the Bi2TexSe3−x nanosheets possess an ultra-broadband nonlinear saturable absorption property covering a range from the visible to the near-infrared band, with the NLO absorption insensitive to the excitation wavelength. This work provide fundamental and systematic insight into the NLO response of Bi2TexSe3−x nanosheets and support their application in photonic devices in the future.

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Z-scan theory of two-photon absorption saturation and experimental evidence

Cited by 72 publications

References 24 publications

Two-photon absorption and optical limiting in tristhiourea cadmium sulphate

Two-photon absorption and optical limiting in tristhiourea cadmium sulphate

Observation of enhanced two-photon absorption in ZnS quantum dots at an ultraviolet wavelength

Ultra-broadband Nonlinear Saturable Absorption for Two-dimensional Bi2TexSe3−x Nanosheets

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