Prof. Bing Gu

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Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 May 2008 in Journal of Applied Physics

Journal Article

Ultrafast optical nonlinearities and figures of merit in acceptor-substituted 3,4,5-trimethoxy chalcone derivatives: Structure-property relationships

Bing Gu

Wei Ji

P. S. Patil

S. M. Dharmaprakash

By performing both

Z

-scan and transient transmission measurements with 130 fs laser pulses in the near infrared region, we investigated structure-property relationships for

χ^{(3)}

in acceptor-substituted 3,4,5-trimethoxy chalcone derivatives. We determined all nonlinear parameters, including two-photon absorption (2PA) cross section, 2PA-induced excited-state absorption (ESA) cross section, microscopic second-order hyperpolarizability, and lifetime of the excited state in these molecules. We found that the microscopic second-order hyperpolarizability

γ_{R}

and 2PA cross section

σ_{2 PA}

in chalcone derivatives increase as the acceptor strength of the molecules increases, which demonstrates an enhancement in optical nonlinearities by simple structural variations. We evaluated the one-photon, two-photon, and effective three-photon figures of merit for acetone solutions of chalcone derivatives at irradiance of

100 GW / {cm}^{2}

. Furthermore, we observed optical limiting behavior in these compounds, which result from both 2PA and 2PA-assisted ESA. These results indicated that chalcone derivatives are a promising candidate for applications on nonlinear photonic devices.

3 March 2008 in Applied Physics Letters

Journal Article

Two-photon-induced excited-state absorption: Theory and experiment

S. M. Dharmaprakash

We develop an open-aperture (OA)

Z

scan and nonlinear transmission theory of two-photon-induced excited-state absorption, under the excitation of spatial Gaussian laser pulses with temporal Gaussian and hyperbolic secant profiles. The found analytic expressions allow us to straightforwardly fit the OA

Z

-scan trace and the nonlinear transmission curve, for convenient extraction of the nonlinear absorption coefficients. As a test, the two-photon-induced excited-state absorption in a chalcone derivative of 3,4-dimethoxy-

4^{'}

-fluorochalcone is explored by performing femtosecond

Z

-scan measurement and is analyzed by our theory.

13 February 2012 in Applied Physics Letters

Journal Article

Spin Hall effect of reflected light from an air-glass interface around the Brewster’s angle

Ling-Jun Kong

Xi-Lin Wang

Si-Min Li

Yongnan Li

Jing Chen

Hui-Tian Wang

We have developed a modified theory of the spin Hall effect of reflected light from a planar interface composed of two dielectric media and obtain the analytical expression valid for any incident angle including the Brewster’s angle. We improved the experimental method and measured the spin-dependent transverse displacement of reflected light from a planar air-glass interface around the Brewster’s angle. The experimental results are in agreement with the theoretical prediction.

26 January 2018 in Photonics Research

Journal Article

Optical forces of focused femtosecond laser pulses on nonlinear optical Rayleigh particles

Liping Gong

Bing Gu

Guanghao Rui

Yiping Cui

Zhuqing Zhu

Qiwen Zhan

The principle of optical trapping is conventionally based on the interaction of optical fields with linear-induced polarizations. However, the optical force originating from the nonlinear polarization becomes significant when nonlinear optical nanoparticles are trapped by femtosecond laser pulses. Herein we develop the time-averaged optical forces on a nonlinear optical nanoparticle using high-repetition-rate femtosecond laser pulses, based on the linear and nonlinear polarization effects. We investigate the dependence of the optical forces on the magnitudes and signs of the refractive nonlinearities. It is found that the self-focusing effect enhances the trapping ability, whereas the self-defocusing effect leads to the splitting of the potential well at the focal plane and destabilizes the optical trap. Our results show good agreement with the reported experimental observations and provide theoretical support for capturing nonlinear optical particles.

19 December 2011 in Optics Express

Journal Article

Two-dimensional microstructures induced by femtosecond vector light fields on silicon

Kai Lou

Sheng-Xia Qian

Xi-Lin Wang

Yongnan Li

Bing Gu

Hui-Tian Wang

We have fabricated the complicated two-dimensional subwave-length microstructures induced by the femtosecond vector light fields on silicon. The fabricated microstructures have the interval between two ripples in microstructures to be around 670–690 nm and the depth of the grooves to be about 300 nm when the pulse fluence of 0.26 J/cm² is slightly higher than the ablated threshold of 0.2 J/cm² for silicon under the irradiation of 100 pulses. The ripples are always perpendicular to the direction of the locally linear polarization. The designable spatial structure of polarization of the femtosecond vector light field can be used to manipulate the fabricated microstructure.

15 October 2007 in Journal of Applied Physics

Journal Article

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

Ya-Xian Fan

In our article [B. Gu, Y. X. Fan, J. Wang, J. Chen, J. P. Ding, H. T. Wang, and B. Guo, Phys. Rev. A 73, 065803 (2006)] we have presented the theory of open-aperture Gaussian-beam Z-scan, based on the Adomian decomposition method, which is available only for the saturable absorption caused by single-photon absorption transition. In the present article, using the same technique (Adomian decomposition method, as a common technique), we develop an open-aperture Z-scan theory for evaluating the property of the saturable absorption originating from two-photon absorption (2PA) transition, when a spatial Gaussian beam is used as the excitation source. We find analytic polynomial expressions of the Z-scan traces for a continuous wave laser or a temporal Gaussian pulsed laser. As the experimental evidence, we investigate the saturable 2PA behaviors caused by the interband two-photon transition in the direct-gap II–VI semiconductors CdS, CdSe, ZnSe, and ZnTe, under the excitation condition of a femtosecond laser with a 140 fs pulse duration, a 1 kHz low repetition rate, and a 1.6 eV photon energy.

About Me

Bing Gu is a professor and researcher at the School of Electronic Science and Engineering, Southeast University. He graduated from the Department of Semiconductor Devices and Microelectronics in 1998 with a B.Sc. From September 2001 to March 2007, he studied for a master’s and doctoral degree in optics at the Department of Physics, Nanjing University, and obtained a D.Sc. He worked at Nanjing Normal University and Nankai University successively. He was a research assistant and visiting scholar at the National University of Singapore and a visiting professor at the University of Dayton. He has been working at the School of Electronic Science and Engineering, Southeast University since March 2012. He is mainly engaged in light field control and nonlinear optics research and conducts research on vector/vortex light fields, optical tweezers technology, nonlinear optical effects excited by new light fields, nonlinear photonic devices, and topological photonics. He won the first prize of the Natural Science Award of the Ministry of Education in 2012, ranking fifth. He is a life member of the Chinese Physical Society, a senior member of the Chinese Optical Society, a member of the Optical Society of America, a member of the International Society of Engineering Optics, etc.

Prof. Bing Gu

Prof. Bing Gu

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