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Optics Express

Junqiao Wang, Jia Zhang, Yongzhi Tian, Chunzhen Fan, Kaijun Mu, Shu Chen, Pei Ding, Erjun Liang
The development of new substrates for surface-enhanced spectroscopy is primarily motivated by the ability to design such substrates to provide the maximum signal enhancement. In this paper, we theoretically design and investigate a crisscross dimer array as a plasmonic substrate for enhancing coherent anti-Stokes Raman scattering (CARS). The plasmonic film-crisscross dimer array system can excite multiple resonances at optical frequencies. By properly designing structure parameters, three plasmon resonances with large field enhancements and same spatial hot spot regions can spectrally match with the pump, Stokes and anti-Stokes beams, respectively...
January 9, 2017: Optics Express
Iman Kundu, Paul Dean, Alexander Valavanis, Li Chen, Lianhe Li, John E Cunningham, Edmund H Linfield, A Giles Davies
We demonstrate quasi-continuous tuning of the emission frequency from coupled cavity terahertz frequency quantum cascade lasers. Such coupled cavity lasers comprise a lasing cavity and a tuning cavity which are optically coupled through a narrow air slit and are operated above and below the lasing threshold current, respectively. The emission frequency of these devices is determined by the Vernier resonance of longitudinal modes in the lasing and the tuning cavities, and can be tuned by applying an index perturbation in the tuning cavity...
January 9, 2017: Optics Express
Shihua Zhang, Liping Yan, Benyong Chen, Zheyi Xu, Jiandong Xie
As the phase delay between the carrier component of the detected interference signal and the carrier has adverse effect for phase generated carrier (PGC) demodulation, it is essential to compensate the phase delay to improve the accuracy of precision displacement measurement in sinusoidal phase-modulation interferometer (SPMI). In this paper, a real-time phase delay compensation method is proposed by regulating a compensating phase introduced to the carrier to maximize the output of the low pass filter so as to make the carrier synchronize with the interference signal...
January 9, 2017: Optics Express
Meng Xiang, Qunbi Zhuge, Meng Qiu, Xinyu Zhou, Ming Tang, Deming Liu, Songnian Fu, David V Plant
We propose a RF-pilot aided modulation format identification (MFI) technique to enable a hitless flexible coherent transceiver with fast format switching. For the MFI, modulation format information is encoded to the amplitude of the RF-pilot, which can be simultaneously used for the compensation of both laser phase noise and fiber nonlinearity. The proposed MFI technique is able to identify arbitrary modulation formats including multi-dimensional formats and hybrid QAM formats. The high accuracy of the proposed MFI scheme is experimentally demonstrated without sacrificing the tolerance of both laser phase noise and fiber nonlinearity for various modulation formats up to dual-polarization (DP) 64QAM...
January 9, 2017: Optics Express
Eiichi Ishida, Kengo Miura, Yuya Shoji, Hideki Yokoi, Tetsuya Mizumoto, Nobuhiko Nishiyama, Shigehisa Arai
We fabricated a magneto-optical (MO) isolator with a TE mode nonreciprocal phase shift. The isolator is based on a Mach-Zehnder interferometer composed of 3-dB directional couplers, a reciprocal phase shifter, and a nonreciprocal phase shifter. To realize TE mode operation in the optical isolator, we designed a novel waveguide structure composed of a hydrogenated amorphous silicon waveguide with an asymmetric MO garnet lateral clad on a garnet substrate. The isolator operation is successfully demonstrated in a fabricated device showing the different transmittances between forward and backward directions...
January 9, 2017: Optics Express
Youliang Jin, Baoan Song, Zhitai Jia, Yinan Zhang, Changgui Lin, Xunsi Wang, Shixun Dai
A tangencypoint method (TPM) is presented to derive the thickness and optical constants of chalcogenide thin films from their transmission spectra. It solves the problem of the abnormal value of thickness in the strong absorption region obtained by Swanepoel method. The accuracy of the thickness and refractive index is better than 0.5% by using this method. Moreover, comparing with Swanepoel method by using the same simulation and experimental data from the transmission spectrum, the accuracy of the thickness and refractive index obtained by the TPM is higher in the strong absorption region...
January 9, 2017: Optics Express
Taka-Aki Yano, Yuta Tsuchimoto, Remo Proietti Zaccaria, Andrea Toma, Alejandro Portela, Masahiko Hara
We perform a comprehensive numerical analysis on the optical binding forces of a multiple-resonant silicon nanodimer induced by the normal illumination of a plane wave in the visible region. The silicon nanodimer provides either repulsive or attractive forces in water while providing only attractive forces in air. The enhancement of the magnetic dipole mode is attributed to the generation of repulsive forces. The sign (attractive/repulsive) and the amplitude of the optical forces are controlled by incident polarization and separation distance between the silicon nanoparticles...
January 9, 2017: Optics Express
Hao Jia, Lei Zhang, Jianfeng Ding, Lingchen Zheng, Chen Yuan, Lin Yang
We experimentally demonstrate a 4 × 4 microring modulator matrix integrated with the asymmetrical directional couplers based mode multiplexer and de-multiplexer photonic circuit for on-chip optical interconnect. The inter-mode optical crosstalk of the device is less than -20 dB in the wavelength range from 1525 nm to 1565 nm. Data transmission with a throughput capacity of 4 × 4 × 32 Gbps is achieved by utilizing four wavelengths and four spatial modes multiplexing. We envision this structure as a potential solution to increase the communication capacity for on-chip interconnect within limited chip area...
January 9, 2017: Optics Express
Aiqin Tian, Jianping Liu, Liqun Zhang, ZengCheng Li, Masao Ikeda, Shuming Zhang, Deyao Li, Pengyan Wen, Feng Zhang, Yang Cheng, Xiaowang Fan, Hui Yang
By observing the morphology evolution of green InGaN/GaN quantum well (QW) and studying the catholuminescence (CL) property, we investigate indium-segregation-related defects that are formed at green InGaN/GaN QW interfaces. Meanwhile, we also propose the approach and suggest the mechanism to remove them for green InGaN/GaN QW grown on both GaN templates and free-standing GaN substrates. By engineering the interface of green InGaN/GaN QWs, we have achieved green laser diode (LD) structure with low threshold current density of 1...
January 9, 2017: Optics Express
You-Jin Lee, Minho Park, Dong-Myung Lee, Chang-Jae Yu, Jae-Hoon Kim
We proposed a half-wall structure in the in-plane switching (IPS) configuration of the nanoencapsulated liquid crystal (LC) display for reducing a driving voltage. The IPS electrodes were fabricated on top of the half-walls to enhance electric field strength through the whole LC layer. In addition, we demonstrated a self-masking process for the half-wall structure and the IPS electrodes without any additional mask-aligning process.
January 9, 2017: Optics Express
J-C Weeber, J Arocas, O Heintz, L Markey, S Viarbitskaya, G Colas-des-Francs, K Hammani, A Dereux, C Hoessbacher, U Koch, J Leuthold, K Rohracher, A L Giesecke, C Porschatis, T Wahlbrink, B Chmielak, N Pleros, D Tsiokos
Dielectric loaded surface plasmon waveguides (DLSPPWs) comprised of polymer ridges deposited on top of CMOS compatible metal thin films are investigated at telecom wavelengths. We perform a direct comparison of the properties of copper (Cu), aluminum (Al), titanium nitride (TiN) and gold (Au) based waveguides by implementing the same plasmonic waveguiding configuration for each metal. The DLSPPWs are characterized by leakage radiation microscopy and a fiber-to-fiber configuration mimicking the cut-back method...
January 9, 2017: Optics Express
Robert Charles Devlin, Antonio Ambrosio, Daniel Wintz, Stefano Luigi Oscurato, Alexander Yutong Zhu, Mohammadreza Khorasaninejad, Jaewon Oh, Pasqualino Maddalena, Federico Capasso
Vortex beams are characterized by a helical wavefront and a phase singularity point on the propagation axis that results in a doughnut-like intensity profile. These beams carry orbital angular momentum proportional to the number of intertwined helices constituting the wavefront. Vortex beams have many applications in optics, such as optical trapping, quantum optics and microscopy. Although beams with such characteristics can be generated holographically, spin-to-orbital angular momentum conversion has attracted considerable interest as a tool to create vortex beams...
January 9, 2017: Optics Express
Kenichi Maeno, Yasushi Takahashi, Tatsuya Nakamura, Takashi Asano, Susumu Noda
We experimentally study photonic crystal L3 nanocavities whose design Q factors (Q<sub>design</sub>) have been improved with the visualization of leaky components design method. The experimental Q values (Q<sub>exp</sub>) are monotonically increased from 6,000 to 2,100,000 by iteratively modifying the positions of some of the air holes, as determined by the referred design method. We investigate the Q<sub>exp</sub> tolerance to imperfections in the fabricated samples, which reveals that the cavities improved by the visualization method tend to lose some tolerance to structural differences between the fabricated samples and the design values...
January 9, 2017: Optics Express
Jian Zhao, Germain Guiraud, Florian Floissat, Benoit Gouhier, Sergio Rota-Rodrigo, Nicholas Traynor, Giorgio Santarelli
Gain dynamics study provides an attractive method to understand the intensity noise behavior in fiber amplifiers. Here, the gain dynamics of a medium power (5 W) clad-pumped Yb-fiber amplifier is experimentally evaluated by measuring the frequency domain transfer functions for the input seed and pump lasers from 10 Hz to 1 MHz. We study gain dynamic behavior of the fiber amplifier in the presence of significant residual pump power (compared to the seed power), showing that the seed transfer function is strongly saturated at low Fourier frequencies while the pump power modulation transfer function is nearly unaffected...
January 9, 2017: Optics Express
L Xu, S Alam, Q Kang, D P Shepherd, D J Richardson
A high-pulse-energy, diffraction-limited, wavelength-selectable, visible source, based on Raman frequency shifting of a frequency-doubled Yb-doped fiber laser, has been studied. The relative length-scaling laws of Raman gain and self-phase modulation push the design towards short fiber lengths with large core size. It is experimentally demonstrated that the Raman clean-up effect in a graded-index multi-mode fiber is not sufficient to obtain diffraction-limited beam quality in the short fiber length. Thus, a large-core photonic crystal fiber is used to maintain diffraction-limited performance and output pulse energies of ~1 μJ, at a 1-MHz repetition rate and 1...
January 9, 2017: Optics Express
Gaetan Friart, Guy Van der Sande, Mulham Khoder, Thomas Erneux, Guy Verschaffelt
With the development of new applications using semiconductor ring lasers (SRLs) subject to optical feedback, the stability properties of their outputs becomes a crucial issue. We propose a systematic bifurcation analysis in order to properly identify the best parameter ranges for either steady or self-pulsating periodic regimes. Unlike conventional semiconductor lasers, we show that SRLs exhibit both types of outputs for large and well defined ranges of the feedback strength. We determine the stability domains in terms of the pump parameter and the feedback phase...
January 9, 2017: Optics Express
Shujun Xing, Xinzhu Sang, Xunbo Yu, Chen Duo, Bo Pang, Xin Gao, Shenwu Yang, YanXin Guan, Binbin Yan, Jinhui Yuan, Kuiru Wang
A high-efficient computer-generated integral imaging (CGII) method is presented based on the backward ray-tracing technique. In traditional CGII methods, the total rendering time is long, because a large number of cameras are established in the virtual world. The ray origin and the ray direction for every pixel in elemental image array are calculated with the backward ray-tracing technique, and the total rendering time can be noticeably reduced. The method is suitable to create high quality integral image without the pseudoscopic problem...
January 9, 2017: Optics Express
Gennady Rasskazov, Anton Ryabtsev, Kriti Charan, Tianyu Wang, Chris Xu, Marcos Dantus
Ultrashort pulse generation in the 1600 nm wavelength region is required for deep-tissue biomedical imaging. We report on the characterization and adaptive compression of a multi-soliton output spanning >300 nm from a large-mode area photonic-crystal fiber rod for two separate laser setups. Sub-30 fs pulses are generated by first compressing of each soliton individually, and then followed by coherently combining all of the pulses in the train, which are separated by hundreds of femtoseconds. Simulations of the source, together with amplitude and phase coherence measurements are provided...
January 9, 2017: Optics Express
Jose Francisco Miras Domenegueti, Acacio A Andrade, Viviane Pilla, Sergio Carlos Zilio
A low-cost single arm double interferometer was developed for the concurrent measurement of linear thermal expansion (α) and thermo-optic (dn/dT) coefficients of transparent samples with plane and parallel surfaces. Owing to its common-path optical arrangement, the device is compact and stable, and allows the simultaneous measurement of interferences arising from a low-finesse Fabry-Perot etalon and from a Mach-Zehnder-type interferometer. The method was demonstrated with measurements of solid (silica, BK7, SF6) and liquid (water, ethanol and acetone) samples...
January 9, 2017: Optics Express
Jinlong Zhang, Xiaoqing Bu, Hongfei Jiao, Bin Ma, Xinbin Cheng, Zhangshan Wang
Broadband low dispersion (BBLD) mirrors are an essential component in femto-second (fs) pulse laser systems. We designed and produced Ta<sub>2</sub>O<sub>5</sub>-HfO<sub>2</sub>/SiO<sub>2</sub> composite quarter-wave and non-quarter-wave HfO<sub>2</sub>/SiO<sub>2</sub> BBLD mirrors for the 30fs petawatt laser system. The laser damage properties of the BBLD mirrors were investigated in an uncompressed sub-nanosecond laser pulse. It showed that the Ta<sub>2</sub>O<sub>5</sub>-HfO<sub>2</sub>/SiO<sub>2</sub> composite BBLD mirror possessed higher LIDT due to the low electric-field intensity (EFI) in the case of the coating without artificial nodules...
January 9, 2017: Optics Express
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