Co-reporter:Dong Wu;Jian-Nan Wang;Li-Gang Niu;Xu Lin Zhang;Si Zhu Wu;Luke P. Lee;Hong Bo Sun
Advanced Optical Materials 2014 Volume 2( Issue 8) pp:751-758
Publication Date(Web):
DOI:10.1002/adom.201400175
The small field-of-view (FOV) limits the range of vision in various detecting/imaging devices from biological microscopes to commercial cameras and military radar. To date, imaging with FOV over 90° has been realized with fish-eye lenses, catadioptric lens, and rotating cameras. However, these devices suffer from inherent imaging distortion and require multiple bulky elements. Inspired by compound eyes found in nature, here a small-size (84 μm), distortion-free, wide-FOV imaging system is presented via an advanced 3D artificial eye architecture. The 3D artificial eye structure is accomplished by exploiting an effective optical strategy — high-speed voxel-modulation laser scanning (HVLS). The eye features a hexagonal shape, high fill factor (FF) (100%), large numerical aperture (NA) (0.4), ultralow surface roughness (2.5 nm) and aspherical profile, which provides high uniformity optics (error < ±6%) and constant resolution (FWHM = 1.7 ± 0.1 μm) in all directions. Quantitative measurement shows the eye reduces imaging distortion by two/three times under 30°/45° incidence, compared with a single lens. The distortion-free FOV can be controlled from 30° to 90°.
Co-reporter:Bin-Bin Xu, Lei Wang, Zhuo-Chen Ma, Ran Zhang, Qi-Dai Chen, Chao Lv, Bing Han, Xin-Ze Xiao, Xu-Lin Zhang, Yong-Lai Zhang, Kosei Ueno, Hiroaki Misawa, and Hong-Bo Sun
ACS Nano 2014 Volume 8(Issue 7) pp:6682
Publication Date(Web):June 4, 2014
DOI:10.1021/nn5029345
We report polarized femtosecond laser-light-mediated growth and programmable assembly of photoreduced silver nanoparticles into triply hierarchical micropatterns. Formation of erected arrays of nanoplates with a thickness as small as λ/27 (λ, the writing laser wavelength) level is demonstrated. The growth mechanism of nanoplates has been clarified: (i) the excited surface plasmons enhance the local electric field and lead to spatially selective growth of silver atoms at the opposite ends of dipoles induced on early created silver seeds; (ii) the optical attractive force overcomes electrostatic repulsion in the enhanced local electric field to assemble the silver nanoparticles directly. The triply hierarchical micropattern shape and location, the nanoplate orientation, and thickness are all attained in controlled fashion.Keywords: laser nanofabrication; nanoplate; SERS; silver; surface plasmons
Co-reporter:Ya-Wei Hao, Hai-Yu Wang, You-Ju Huang, Bing-Rong Gao, Qi-Dai Chen, Liang-Bin Li and Hong-Bo Sun
Journal of Materials Chemistry A 2013 vol. 1(Issue 34) pp:5244-5249
Publication Date(Web):11 Jun 2013
DOI:10.1039/C3TC30879K
The excited state relaxation of two types of azobenzene derivative excited at 350 nm in the short-wavelength (S2(π, π*)) band was studied by transient absorption spectroscopy. We compared the relaxation dynamics and the time-resolved anisotropic relaxation properties of these two molecules in liquid solution and in bulk film. The average relaxation life-time for Azo-2 in bulk film (13.2 ps) is much slower than that of Azo-2 (4.06 ps) and Azo-1(1.31 ps) in liquid solution. The time-resolved polarization anisotropy spectroscopy measurements of these samples also showed significant differences. The value of anisotropy for Azo-2 remained almost constant at about 0.2 in bulk film but decayed slowly from 0.3 in liquid solution. The value for Azo-1 in liquid solution decayed very fast from 0.4 to 0.2 within 6 ps. Our results gave new evidence for the existence of a converted inversion channel. We also concluded that the concerted inversion process and the conventional rotation process govern the relaxation for the photon-induced switches of azobenzene and its derivatives under short-wavelength band excitation.
Co-reporter:Lin Ren, De-Gong Wang, Li-Gang Niu, Bin-Bin Xu, Jun-Feng Song, Qi-Dai Chen and Hong-Bo Sun
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 24) pp:9590-9593
Publication Date(Web):22 Mar 2013
DOI:10.1039/C3CP44051F
We report the fabrication of three-dimensional periodic metal nickel nanostructures achieved by the combination of femtosecond laser-induced two-photon polymerization and electroless plating technology. We can control the deposition speed of 10 nm per second by adjusting the reaction time. The thermal stability is good under 500 °C for the three-dimensional graphite-lattice polymer structure with 200 nm nickel film. Optical reflectivity and thermal emission measurements under 550 °C showed that the fabricated metallic structure was thermally excited and emitted light at λ = 4.50, 4.95 μm. The emission peak wavelengths agree with the absorption peaks. These data demonstrate that creating metallic photonic crystals by incorporation of metals to laser-fabricated templates is a simple and cost-efficient method. The emitters can work at such low temperatures, which is more important for realistic operation in applications.
Co-reporter:Bin-Bin Xu, Ran Zhang, Huan Wang, Xue-Qing Liu, Lei Wang, Zhuo-Chen Ma, Qi-Dai Chen, Xin-Ze Xiao, Bing Han and Hong-Bo Sun
Nanoscale 2012 vol. 4(Issue 22) pp:6955-6958
Publication Date(Web):28 Aug 2012
DOI:10.1039/C2NR31614E
Gold nanodots were used as the precursory material to form micronanopatterns under pinpoint scanning by a tightly focused femtosecond laser beam. Different from the widely reported metal ions photoreduction mechanism, here gradient force in an optical trap generated around the laser focus is considered as the major mechanism for particle accumulation (focusing). It has been proven to be an effective method for gold micronanostructure fabrication, and the electronic resistivity of the resulting metals reached as high as 5.5 × 10−8 Ω m, only twice that of the bulk material (2.4 × 10−8 Ω m). This merit makes it a novel free interconnection technology for micronanodevice fabrication.
Co-reporter:Ran Zhang, Bin-Bin Xu, Xue-Qing Liu, Yong-Lai Zhang, Ying Xu, Qi-Dai Chen and Hong-Bo Sun
Chemical Communications 2012 vol. 48(Issue 47) pp:5913-5915
Publication Date(Web):25 Apr 2012
DOI:10.1039/C2CC31604H
We present a facile production approach to highly efficient SERS test strips by physical vapor deposition of silver on paper, which contains natural wrinkle and fibril structures. The SERS test strips open the door to highly sensitive (e.g., 10−10 M) SERS detection in a convenient fashion.
Co-reporter:Dong Wu;Jian-Nan Wang;Si-Zhu Wu;Shuai Zhao;Hao Zhang;Hong-Bo Sun;Lei Jiang
Advanced Functional Materials 2011 Volume 21( Issue 15) pp:2927-2932
Publication Date(Web):
DOI:10.1002/adfm.201002733
Abstract
Rice leaves with anisotropic sliding properties have the ability to directionally control the movement of water microdroplets. However, the realization of artificial anisotropic sliding biosurfaces has remained challenging. It is found, by a systematic investigation, that the height of 200-μm-width groove arrays on rice leaves reaches up to 45 μm, far greater than the smaller microgrooves that are widely adopted for the study of anisotropic wetting. A new model based on three-level microstructures (macro/micro/nano) is developed to interpret the anisotropic sliding behavior. Moreover, artificial rice leaves with different macrogrooves are demonstrated by combining micro/nanostructures and macrogrooves, which are prepared by photolithography, PDMS imprinting, and micro/nanostructure coating. Sliding-angle measurement further prove that the third-level macrogroove arrays are the determining factor for anisotropic sliding. Finally, a new testing method, curvature-assisted droplet oscillation (CADO), is developed to quantitatively reveal the anisotropic dynamic behavior of biomimetic rice-leaf-like surfaces.
Co-reporter:Jie Yang ; Hong-Hua Fang ; Ran Ding ; Shi-Yang Lu ; Yong-Lai Zhang ; Qi-Dai Chen ;Hong-Bo Sun
The Journal of Physical Chemistry C 2011 Volume 115(Issue 18) pp:9171-9175
Publication Date(Web):April 20, 2011
DOI:10.1021/jp110646n
We have developed an improved physical vapor transport method. This method enables us to decrease the sublimation temperature of small organic molecules, and slow the weight loss process, and then regulate the degree of vapor saturation of materials. Large-size single-crystalline materials with high quality are successfully prepared from small organic functional molecules. The slice crystals are found to be single crystalline with high quality. The surface morphologies and structural information of grown crystals were characterized by optical microscope, atomic force microscopy (AFM), and X-ray diffraction (XRD) analysis. The results indicate that the growth mechanism of single crystals is a 2D nucleation, with elementary steps, large straight steps, and layer-by-layer growth.
Co-reporter:Hong Xia;Juan Wang;Ye Tian;Xiao-Bo Du;Yong-Lai Zhang;Yan He;Hong-Bo Sun
Advanced Materials 2010 Volume 22( Issue 29) pp:
Publication Date(Web):
DOI:10.1002/adma.201090096
Co-reporter:Hong Xia;Juan Wang;Ye Tian;Xiao-Bo Du;Yong-Lai Zhang;Yan He;Hong-Bo Sun
Advanced Materials 2010 Volume 22( Issue 29) pp:3204-3207
Publication Date(Web):
DOI:10.1002/adma.201000542
Co-reporter:Juan Wang, Yan He, Hong Xia, Li-Gang Niu, Ran Zhang, Qi-Dai Chen, Yong-Lai Zhang, Yan-Feng Li, Shao-Jiang Zeng, Jian-Hua Qin, Bing-Cheng Lin and Hong-Bo Sun
Lab on a Chip 2010 vol. 10(Issue 15) pp:1993-1996
Publication Date(Web):27 May 2010
DOI:10.1039/C003264F
This paper demonstrates the embellishment of existing microfluidic devices with integrated three dimensional (3D) micronanostructures via femtosecond laser micronanofabrication, which, for the first time, proves two-photon photopolymerization (TPP) to be a powerful technology for chip functionalization. As representative examples, microsieves with various pore shape and adjustable pore size were successfully fabricated inside a conventional glass-based microfluidic channel prepared by wet etching for microparticle separation. Moreover, a fish scale like microfilter was also fabricated and appointed as a one-way valve, which showed excellent performance as we expected. These results indicate that such embellishment of microfluidic devices is simple, low cost, flexible and easy to access. We believe that, combined with TPP, the application of lab-on-chip devices would be further extended.
Co-reporter:Si-Zhu Wu, Dong Wu, Jia Yao, Qi-Dai Chen, Jian-Nan Wang, Li-Gang Niu, Hong-Hua Fang and Hong-Bo Sun
Langmuir 2010 Volume 26(Issue 14) pp:12012-12016
Publication Date(Web):May 25, 2010
DOI:10.1021/la1015753
In this paper, one simple method to control two-direction anisotropic wetting by regular micropearl arrays was demonstrated. Various micropearl arrays with large area were rapidly fabricated by a kind of improved laser interference lithography. Specially, we found that the parallel contact angle (CA) θ2 decreased from 93° to 67° as the intensity ratio of four laser beams increased from 2:1 to 30:1, while the perpendicular CA θ1 determined by the thickness of the resin remained constant. This was interpreted as the decrease of height variations Δh from 1100 to 200 nm along the parallel direction caused by the increase of the intensity ratio. According to this rule, both θ1 and θ2 could be simultaneously controlled by adjusting the height variation Δh and the resin thickness. Moreover, by combining appropriate design and low surface energy modification, a natural anisotropic rice leaf exhibiting CAs of 146° ± 2°/153° ± 3° could be mimicked by our anisotropic biosurface with the CAs 145° ± 1°/150° ± 2°. We believe that these controlled anisotropic biosurfaces will be helpful for designing smart, fluid-controllable interfaces that may be applied in novel microfluidic devices, evaporation-driven micro/nanostructures, and liquid microdroplet directional transfer.
Co-reporter:Ran Zhang, Bin-Bin Xu, Xue-Qing Liu, Yong-Lai Zhang, Ying Xu, Qi-Dai Chen and Hong-Bo Sun
Chemical Communications 2012 - vol. 48(Issue 47) pp:NaN5915-5915
Publication Date(Web):2012/04/25
DOI:10.1039/C2CC31604H
We present a facile production approach to highly efficient SERS test strips by physical vapor deposition of silver on paper, which contains natural wrinkle and fibril structures. The SERS test strips open the door to highly sensitive (e.g., 10−10 M) SERS detection in a convenient fashion.
Co-reporter:Lin Ren, De-Gong Wang, Li-Gang Niu, Bin-Bin Xu, Jun-Feng Song, Qi-Dai Chen and Hong-Bo Sun
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 24) pp:NaN9593-9593
Publication Date(Web):2013/03/22
DOI:10.1039/C3CP44051F
We report the fabrication of three-dimensional periodic metal nickel nanostructures achieved by the combination of femtosecond laser-induced two-photon polymerization and electroless plating technology. We can control the deposition speed of 10 nm per second by adjusting the reaction time. The thermal stability is good under 500 °C for the three-dimensional graphite-lattice polymer structure with 200 nm nickel film. Optical reflectivity and thermal emission measurements under 550 °C showed that the fabricated metallic structure was thermally excited and emitted light at λ = 4.50, 4.95 μm. The emission peak wavelengths agree with the absorption peaks. These data demonstrate that creating metallic photonic crystals by incorporation of metals to laser-fabricated templates is a simple and cost-efficient method. The emitters can work at such low temperatures, which is more important for realistic operation in applications.
Co-reporter:Ya-Wei Hao, Hai-Yu Wang, You-Ju Huang, Bing-Rong Gao, Qi-Dai Chen, Liang-Bin Li and Hong-Bo Sun
Journal of Materials Chemistry A 2013 - vol. 1(Issue 34) pp:NaN5249-5249
Publication Date(Web):2013/06/11
DOI:10.1039/C3TC30879K
The excited state relaxation of two types of azobenzene derivative excited at 350 nm in the short-wavelength (S2(π, π*)) band was studied by transient absorption spectroscopy. We compared the relaxation dynamics and the time-resolved anisotropic relaxation properties of these two molecules in liquid solution and in bulk film. The average relaxation life-time for Azo-2 in bulk film (13.2 ps) is much slower than that of Azo-2 (4.06 ps) and Azo-1(1.31 ps) in liquid solution. The time-resolved polarization anisotropy spectroscopy measurements of these samples also showed significant differences. The value of anisotropy for Azo-2 remained almost constant at about 0.2 in bulk film but decayed slowly from 0.3 in liquid solution. The value for Azo-1 in liquid solution decayed very fast from 0.4 to 0.2 within 6 ps. Our results gave new evidence for the existence of a converted inversion channel. We also concluded that the concerted inversion process and the conventional rotation process govern the relaxation for the photon-induced switches of azobenzene and its derivatives under short-wavelength band excitation.
