A 1.8 μm optical parametric oscillator pumped by a diode end-pumped acousto-optically Q-switched Nd:YAG is demonstrated. A 30-mm-long KTiOPO 4 crystal cut with an angle of θ = 59.4, φ = 0 is employed as the OPO crystal. 685 mW signal laser at 1.8 μm is obtained at the diode pump power of 13 W and the pulse repetition rate of 25 kHz. Simultaneously, 265 mW idler emission at 2.6 μm is obtained. The corresponded diode-to-OPO conversion efficiency is 7.3%. The pulse width of the signal and idler wave are measured to be 4.5 and 2.5 ns, respectively. This gives a peak power of 6.1 and 4.2 kW, respectively. © 2012 Pleiades Publishing, Ltd.

Bai Fen;Wang Qingpu;Liu Zhaojun;Zhang Xingyu;Wan Xuebin;Lan Weixia;Shen Hongbin;Zhang Sasa;Jin Guofan

Laser Physics

2012

A diode-pumped passively Q-switched Nd:YAG/BaWO4/KTP yellow laser is presented for the first time. The obtained maximum average output power, conversion efficiency, pulse energy were 1.21 W, 9.06%, and 68.5 μJ, respectively. © OSA 2012.

Xu Huihua;Zhang Xingyu;Wang Qingpu;Wang Weitao;Wang Cong;Li Lei;Cong Zhenhua;Liu Zhaojun;Chen Xiaohan;Fan Shuzhen;Jin Guofan;Zhang Huaijin

CLEO Applications and Technology CLEO at 2012

2012

Zhang Haosu;Zhu Jun;Zhu Zhendong;Jin Guofan

Optical Engineering

2014

Plasmonic nanostructures separated by nanogaps enable strong electromagnetic-field confinement on the nanoscale for enhancing light-matter interactions, which are in great demand in many applications such as surface-enhanced Raman scattering (SERS). A simple M-shaped nanograting with narrow V-shaped grooves is proposed. Both theoretical and experimental studies reveal that the electromagnetic field on the surface of the M grating can be pronouncedly enhanced over that of a grating without such grooves, due to field localization in the nanogaps formed by the narrow V grooves. A technique based on room-temperature nanoimprinting lithography and anisotropic reactive-ion etching is developed to fabricate this device, which is cost-effective, reliable, and suitable for fabricating large-area nanostructures. As a demonstration of the potential application of this device, the M grating is used as a SERS substrate for probing Rhodamine 6G molecules. Experimentally, an average SERS enhancement factor as high as 5×10⁸ has been achieved, which verifies the greatly enhanced light-matter interaction on the surface of the M grating over that of traditional SERS surfaces. M for Nano: An M-shaped plasmonic nanograting with nanogaps is proposed and fabricated by using room-temperature nanoimprinting and anisotropic reactive-ion etching, and enables strong field localization in the nanogaps. Surface-enhanced Raman scattering (SERS) experiments show an average SERS enhancement factor as high as 5×10⁸ by using the M-grating substrate, which reveals its potential as a replicable, large-area, highly active SERS substrate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhu Zhendong;Bai Benfeng;Zhang Haosu;Zhang Mingqian;You Oubo;Tan Qiaofeng;Wang Jia;Jin Guofan;Li Qunqing;Fan Shoushan;Duan Huigao

Small

2014

Multiple three-dimensional (3D) display technologies are reviewed. The display mechanisms discussed in this paper are classified into two categories: holographic display in wave optics and light field display in ray optics, which present the 3D optical wave field in two different ways. Key technical characteristics of the optical systems and the depth cues of human visual system are analyzed. It is to be expected that these 3D display technologies will achieve practical applications with the increase of the optical system bandwidth. © 2014 Chinese Optics Letters.

Zhang Hao;Zhao Yan;Cao Liangcai;Jin Guofan

Chinese Optics Letters

2014

© 2014 SPIE. The emerging field of metasurfaces has offered unprecedented functionalities for shaping wave fronts and optical responses. Here, we realize a new class of metasurfaces with nanorod array, which can generate abrupt interfacial phase changes to control local wave front at subwavelength scale. The physical mechanism under the phase modulation is geometry phase in essence, thus can achieve broadband operation, as well as helicity-dependent property. Multiple applications have been demonstrated, such as anomalous refraction, ultrathin dual-polarity metalenses, helicity-dependent unidirectional surface plasmon polariton (SPP) excitation, and three-dimensional (3D) holography.

Huang Lingling;Bai Benfeng;Tan Qiaofeng;Jin Guofan;Chen Xianzhong;Zhang Shuang;Zentgraf Thomas

Proceedings of SPIE the International Society for Optical Engineering

2014

© 2016 Elsevier B.V. This article proposes a surface-plasmon-enhanced GaN-LED based on the multilayered rectangular nano-grating. This structure contains a SiO2 film, an Ag film and a HfO2 film sequentially coated on the rectangularly-patterned p-GaN layer. The Ag film is used to enhance the internal quantum efficiency. The HfO2 cover-layer symmetrizes the distribution of refractive index besides the Ag film to improve the light extraction efficiency and surface-plasmon (SP) extraction efficiency. The inserted SiO2 layer is utilized to further improve the SP extraction efficiency. The properties of SP modes and Purcell effect in this structure are investigated. The photoluminescence experiments demonstrate that its peak intensity of top-emission is about 2.5 times greater than that from the reference structure covered by a single-layer Ag film on the rectangularly-patterned p-GaN layer.

Zhu Jun;Zhang Haosu;Zhu Zhendong;Jin Guofan;Li Qunqing

Optics Communications

2017

© OSA 2016. We propose an efficient algorithm using layered stereogram based inverse Fresnel diffraction for 3-D computer-generated holograms. Experiments demonstrate the proposed method can reconstruct quality 3-D images with accurate depth cues.

Zhang Hao;Cao Liangcai;Zong Song;Jin Guofan

Optics Infobase Conference Papers

2016

© 2017, Tsinghua University Press and Springer-Verlag Berlin Heidelberg. Multistep plasmonic nanostructures can induce the deep modulation of electromagnetic-field interactions on the nanoscale for positioning hotspots, and this generation of enhanced fields is important in many optical applications. In this article, a new strategy is proposed for fabricating a plasmonic doublestacked nanocone (DSC) nanostructure. In the DSC structure, a tunable plasmonic hybrid mode proceeds from the strong coupling of the plasmonic resonance of a fundamental cavity mode with a localized surface plasmon gap mode. In the nanostructure, the far-field response is deeply modulated and the hottest spots can be effectively positioned on the top surface of the DSC nanostructure. A controllable and cost-effective mask-reconfiguration technique for manufacturing the multiscale nanostructure is developed, which guarantees the generation of the introduced crucial stage on the DSC nanostructure. To evaluate the features of the plasmonic resonance, the DSC nanostructure is used as a surface-enhanced Raman scattering (SERS) substrate for detecting 4-mercaptopyridine molecules under specific excitation conditions. Its good performance, with an average measured SERS enhancement factor as high as 10⁸, demonstrates its strong plasmonic-mode hybridization and extreme field enhancement. [Figure not available: see fulltext.].

Zhu Zhendong;Gao Sitian;Li Wei;Shi Yushu;Wang Xueshen;Wang Qixia;Zeng Fa;You Oubo;Bai Benfeng;Tan Qiaofeng;Jin Guofan;Li Qunqing;Fan Shoushan

Nano Research

2017

© 2018 Optical Society of America. Grating-based single-shot digital lens-free holography with spatial spectral multiplexing is proposed to realize full field-of-view (FOV) imaging for weak-scattering objects. Multiple object waves are generated by a one-dimensional grating that is placed in near contact with the object to avoid the cross talk among different diffraction orders during reconstruction. A multiplexed off-axis hologram is created by interference between the object waves and reference wave and captured by an image sensor in one shot. Multiple imaging areas corresponding to the captured object waves can be simultaneously retrieved during reconstruction. A formula which guarantees full FOV imaging without cross talk or information loss is presented. The imaging experiments of a USAF resolution target are presented to demonstrate the feasibility of this method.

Zhang Wenhui;Cao Liangcai;Jin Guofan;Brady David

Applied Optics

2018