Optimization of nonlinear optical properties of ZnO micro and nanocrystals for biophotonics

Urban, Ben E.; Lin, Jie; Kumar, O. S. Sunish; Senthilkumar, K.; Fujita, Yasuhisa; Neogi, Arup

doi:10.1364/ome.1.000658

Cited by 34 publications

(24 citation statements)

References 22 publications

(43 reference statements)

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“…A slope close to 2 on the log–log plot indicated a nonlinear two‐photon absorption process. At the same time, second‐harmonic generation and hyper‐Rayleigh scattering, observed in case of MPM of zinc oxide and silver nanoparticles, are ruled out as the mechanisms underlying the observed Zn(PT) 2 PL as signals generated by these processes are spectrally shifted relative to the excitation wavelength shift . No spectral shift in the emission wavelength of Zn(PT) 2 was observed when the excitation wavelength shifted.…”

Section: Resultsmentioning

confidence: 90%

Optical Characterization of Zinc Pyrithione

Sandiford

Holmes

Mangion

et al. 2019

Photochem & Photobiology

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Zinc pyrithione is ubiquitous in commercial products particularly antidandruff shampoos. For the efficacy of zinc pyrithione therapeutic cleansers to be assessed accurately, the distribution of particles on the scalp needs to be visualized. Currently, no technique is available which provides the chemical specificity and sensitivity required. Here, we report application of fluorescence‐lifetime imaging microscopy (FLIM) for high‐contrast mapping of zinc pyrithione distribution on the scalp. Characterization of the zinc pyrithione emission by using both one‐photon excitation at five specific wavelengths and two‐photon excitation in the range of 740–820 nm revealed its FLIM fingerprint—a characteristic short average time‐weighted emission lifetime of ΤZnPT = 250 ps. Bandpass‐filtering FLIM signals at ΤZnPT enabled an efficient discrimination between the zinc pyrithione and major endogenous skin species in comparison with that of the conventional reflectance confocal microscopy. Our findings provide means for in vivo high‐sensitivity assaying and high‐contrast imaging of zinc pyrithione in biological systems.

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Section: Resultsmentioning

confidence: 90%

Optical Characterization of Zinc Pyrithione

Sandiford

Holmes

Mangion

et al. 2019

Photochem & Photobiology

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“…Very recently, use of less toxic and biodegradable polymers during synthesis of ZnO NPs has attracted a lot of research attention due to their potential applicability in targeted drug delivery, bioimaging, and in biophotonic devices [40,41]. Use of biodegradable capping agent such as poly vinyl alcohol (PVA) during synthesis of ZnO NPs has been studied [42,43] and it has been observed that surface-capping by PVA leads to hydrophobicity, enhanced compatibility with organic phases, UV-shielding ability of ZnO NPs.…”

Section: Introductionmentioning

confidence: 99%

Red shift of the band-edge photoluminescence emission and effects of annealing and capping agent on structural and optical properties of ZnO nanoparticles

Verma

Kole

Kumbhakar

2015

Journal of Alloys and Compounds

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“…Among these properties, the optical properties of ZnO nanowires or NRs have been the focus of many studies because this kind of nanoobjects can be easily synthesized and has potential applications in making optoelectronic devices. In recent years, the nonlinear optical properties of ZnO nanoobjects have attracted much attention owing to their possible applications in the field of biophotonics [23][24][25]. Under the excitation of a femtosecond (fs) laser in the near infrared region, upconverted signals such as second harmonic generation (SHG) [26] and two-photon-induced luminescence (TPL) [27][28][29] can be generated in ZnO nanoobjects, making them attractive and promising candidates for bioimaging.…”

Section: Introductionmentioning

confidence: 99%

Competition between second harmonic generation and two-photon-induced luminescence in single, double and multiple ZnO nanorods

Dai¹,

Zeng²,

Lan³

et al. 2013

Opt. Express

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The nonlinear optical properties of single, double and multiple ZnO nanorods (NRs) were investigated by using a focused femtosecond (fs) laser beam. The excitation wavelength of the fs laser was intentionally chosen to be 754 nm at which the energy of two photons is slightly larger than that of the exciton ground state but smaller than the bandgap energy of ZnO. Second harmonic generation (SHG) or/and two-photon-induced luminescence (TPL) were observed and their dependences on excitation density were examined. For single ZnO NRs, only SHG was observed even at the highest excitation density we used in the experiments. The situation was changed when the joint point of two ZnO NRs perpendicular to each other was excited. In this case, TPL could be detected at low excitation densities and it increased rapidly with increasing excitation density. At the highest excitation density of ~15 MW/cm(2), the intensity of the TPL became comparable to that of the SHG. For an ensemble of ZnO NRs packed closely, a rapid increase of TPL with a slope of more than 7.0 and a gradual saturation of SHG with a slope of ~0.34 were found at high excitation densities. Consequently, the nonlinear response spectrum was eventually dominated by the TPL at high excitation densities and the SHG appeared to be very weak. We interpret this phenomenon by considering both the difference in electric field distribution and the effect of heat accumulation. It is suggested that the electric field enhancement in double and multiple NRs plays a crucial role in determining the nonlinear response of the NRs. In addition, the reduction in the bandgap energy induced by the heat accumulation effect also leads to the significant change in nonlinear response. This explanation is supported by the calculation of the electric field distribution using the discrete dipole approximation method and the simulation of temperature rise in different ZnO NRs based on the finite element method.

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Optimization of nonlinear optical properties of ZnO micro and nanocrystals for biophotonics

Cited by 34 publications

References 22 publications

Optical Characterization of Zinc Pyrithione

Optical Characterization of Zinc Pyrithione

Red shift of the band-edge photoluminescence emission and effects of annealing and capping agent on structural and optical properties of ZnO nanoparticles

Competition between second harmonic generation and two-photon-induced luminescence in single, double and multiple ZnO nanorods

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