Jianping Ding

Generation of arbitrary vector beams with a spatial light modulator and a common path interferometric arrangement

We describe a convenient approach for generating arbitrary vector beams in a 4-f system with a spatial light modulator (SLM) and a common path interferometric arrangement. A computer-generated hologram is introduced onto SLM for performing the beam conversion. Optical realization of a variety of polarization configurations confirms the reliability and flexibility of our method.

A new type of vector fields with hybrid states of polarization

We present an idea based on Poincaré sphere and demonstrate the creation of a new type of vector fields, which have hybrid states of polarization. Such a type of hybridly polarized vector fields have completely different property from the reported scalar and vector fields. The novel vector fields are anticipated to result in new effects, phenomena, and applications.

Optical trapping with focused Airy beams.

Airy beams are attractive owing to their two intriguing properties--self-bending and nondiffraction--that are particularly helpful for optical manipulation of particles. We perform theoretical and experimental investigations into the focusing property of Airy beams and provide insight into the trapping ability of tightly focused Airy beams. Experiment on optical tweezers demonstrates that the focused Airy beams can create multiple traps for two-dimensional confining particles, and the stable traps exist in the vicinity of the main intensity lobes in the focused beams. The trapping pattern can be varied with changes in the cross section of the focused beam. The focused Airy beam offers a novel way of optically manipulating microparticles.

Generation of vector beam with space-variant distribution of both polarization and phase

We present an idea to generate an arbitrary space-variant vector beam with structured polarization and phase distributions. The vector beams are synthesized from the left- and right-hand polarized light, each carrying different phase distributions. Both the phase and the state of polarization of vector beams can be tailored independently and dynamically by a spatial light modulator.

Radial Hilbert transform with Laguerre-Gaussian spatial filters

We analyze the point spread function (PSF) of the image processing system for radial Hilbert transform and propose a novel spiral phase filter, called the Laguerre-Gaussian spatial filter (LGSF). Theoretical analysis and real experiments show that the LGSF possesses some advantages in comparison with the conventional spiral phase plate (SPP). For example, the PSF of the imaging system with a LGSF presents smaller suboscillations than that with the conventional SPP, which allows us to realize a radial Hilbert transform for achieving a high contrast edge enhancement with high resolution.

Giant optical nonlinearity of a Bi2Nd2Ti3O12 ferroelectric thin film

We investigate the optical nonlinearity of a Bi2Nd2Ti3O4 ferroelectric thin film using the top-hat Z scan technique at a wavelength of 532nm with 35ps duration pulses. The film exhibits the fast and giant optical nonlinearities having the two-photon absorption coefficient of 3.1×104cm∕GW and the nonlinear refraction coefficient of 0.7cm2∕GW, respectively. The mechanism of the optical nonlinearity is discussed in detail. In particular, we also give two important formulas for the top-hat Z scan, which are very valuable and helpful for estimating the nonlinear optical coefficients when the material possesses the simultaneous nonlinear absorption and nonlinear refraction.

Hybridized surface plasmon polaritons at an interface between a metal and a uniaxial crystal

This work is supported in part by NSFC under Grant No. n10325417, by the State Key Program for Basic Research of nChina under Grant No. 2006CB921805, and by the 111 nProject under Grant No. B07026.

Z-scan theory for material with two- and three-photon absorption

We present a theoretical study on the Z-scan characteristics of thin nonlinear optical media with simultaneous two- and three-photon absorption, a situation that exists, for example, in polydiacetylenes. With the introduction of a coupling function between two- and three-photon absorption, we find a quasi-analytic expression for open aperture Z-scan traces. We make a comparison of the analytic solutions with numerical solutions in detail, showing that they are in good agreement. This theoretical result allows us to easily identify and determine simultaneously the two- and three-photon absorption coefficients from the open aperture Z-scan traces.

Two-dimensional wave-front reconstruction from lateral shearing interferograms.

An algorithm is proposed to reconstruct two-dimensional wave-front from phase differences measured by lateral shearing interferometer. Two one-dimensional phase profiles of object wave-front are computed using Fourier transform from phase differences, and then the two-dimensional wave-front distribution is retrieved by use of least-square fitting. The algorithm allows large shear amount and works fast based on fast Fourier transform. Investigations into reconstruction accuracy and reliability are carried out by numerical experiments, in which effects of different shear amounts and noises on reconstruction accuracy are evaluated. Optical measurement is made in a lateral shearing interferometer based on double-grating.

Theory of Gaussian beam Z scan with simultaneous third- and fifth-order nonlinear refraction based on a Gaussian decomposition method

We present a detailed theoretical investigation on the Gaussian beam Z scan for arbitrary aperture and arbitrary nonlinear refraction phase shifts, based on the Gaussian decomposition method, including cases when the medium exhibits the single (2n+1)th-order nonlinear refraction effect and the simultaneous third- and fifth-order nonlinear refraction effects. We find the optimum sum upper limit, which is of great importance to fit the Z-scan traces and extract the nonlinear refraction coefficients related to the third- and fifth-order effects. This method has not only a high accuracy but is also time saving. We also discuss the influence of two-photon absorption on the Z-scan traces when materials possess the simultaneous third- and fifth-order nonlinear refraction effects associated with the two-photon absorption using the fast Fourier transform.