Contents
2015
Volume: 3 Issue 5
24 Article(s)
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Fiber Optics and Optical Communications
Mode converter based on dual-core all-solid photonic bandgap fiber
YongJun Zhang, Yuan Wang, ShanYong Cai, MingYing Lan... and WanYi Gu|Show fewer author(s)
In this paper, we present a mode-selective coupler based on a dual-core all-solid photonic bandgap fiber (AS-PBGF). Because they are all-solid, AS-PBGF-based mode converters are easier to splice to other fibers than those based on air-hole photonic crystal fibers. Mode conversions between the LP01 and LP11 modes, LP01 In this paper, we present a mode-selective coupler based on a dual-core all-solid photonic bandgap fiber (AS-PBGF). Because they are all-solid, AS-PBGF-based mode converters are easier to splice to other fibers than those based on air-hole photonic crystal fibers. Mode conversions between the LP01 and LP11 modes, LP01 and LP21 modes, and LP01 and LP01 modes are obtained at the wavelength λ _ 1550 nm. The 3 dB wavelength bandwidth of these mode converters are 47.8, 20.3, and 20.3 nm, respectively..
Photonics Research
- Publication Date: Aug. 13, 2015
- Vol. 3, Issue 5, 220 (2015)
Theoretical investigation of core mode cut-off condition for tapered multicore fiber
Xuanfeng Zhou, Zilun Chen, Hang Zhou, and Jing Hou
Core mode cutoff is a useful concept not only for a tapered single-core fiber (SCF) but also for a tapered multicore fiber (MCF) to realize cladding mode transmission. In this paper, cut-off conditions of either core mode for tapered SCFs or supermodes for MCFs are theoretically investigated. Rigorous analytical formulCore mode cutoff is a useful concept not only for a tapered single-core fiber (SCF) but also for a tapered multicore fiber (MCF) to realize cladding mode transmission. In this paper, cut-off conditions of either core mode for tapered SCFs or supermodes for MCFs are theoretically investigated. Rigorous analytical formulas are derived for the modes of SCF by a three-layer waveguide model, and an approximation formula of the cut-off condition is given for the LP01 mode. The supermodes of MCFs are analyzed by the coupling mode theory, and the cut-off condition is calculated by a numerical method. Simulation results show that the in-phase supermode of MCFs has a similar cut-off condition with that of SCF. Based on this property, a convenient approximate formula is given to estimate the cut-off condition of the in-phase supermode for tapered MCFs..
Photonics Research
- Publication Date: Aug. 14, 2015
- Vol. 3, Issue 5, 224 (2015)
Image Processing
High-resolution pseudo-inverse ghost imaging
Wenlin Gong
We present a pseudo-inverse ghost imaging (PGI) technique which can dramatically enhance the spatial transverse resolution of pseudo-thermal ghost imaging (GI). In comparison with conventional GI, PGI can break the limitation on the imaging resolution imposed by the speckle’s transverse size on the object plane and alsWe present a pseudo-inverse ghost imaging (PGI) technique which can dramatically enhance the spatial transverse resolution of pseudo-thermal ghost imaging (GI). In comparison with conventional GI, PGI can break the limitation on the imaging resolution imposed by the speckle’s transverse size on the object plane and also enables the reconstruction of an N-pixel image from much less than N measurements. This feature also allows high-resolution imaging of gray-scale objects. Experimental and numerical data assessing the performance of the technique are presented..
Photonics Research
- Publication Date: Aug. 21, 2015
- Vol. 3, Issue 5, 234 (2015)
Imaging Systems
Nonorthogonal object identification based on ghost imaging
Xiaofan Gu, and Shengmei Zhao
Ghost imaging could be used to make a quick identification of orthogonal objects by means of photocurrent correlation measurements. In this paper, we extend the method to identify nonorthogonal objects. In the method, an object is illuminated by one photon from an entangled pair, and the other one is diffracted into a Ghost imaging could be used to make a quick identification of orthogonal objects by means of photocurrent correlation measurements. In this paper, we extend the method to identify nonorthogonal objects. In the method, an object is illuminated by one photon from an entangled pair, and the other one is diffracted into a particular direction by a pre-established multiple-exposure hologram in the idler arm. By the correlation measurements, the nonorthogonal object in the signal arm could be discriminated within a very short time. The constraints for the identification of nonorthogonal objects are presented, which show that the nonorthogonal objects can be discriminated when the overlapping portion between any two objects is less than half of all the objects in the set. The numerical simulations further verify the result..
Photonics Research
- Publication Date: Aug. 24, 2015
- Vol. 3, Issue 5, 238 (2015)
INTEGRATED PHOTONICS: CHALLENGES and PERSPECTIVES
Quantum dot lasers for silicon photonics [Invited]
Alan Y. Liu, Sudharsanan Srinivasan, Justin Norman, Arthur C. Gossard, and John E. Bowers
We review recent advances in the field of quantum dot lasers on silicon. A summary of device performance, reliability, and comparison with similar quantum well lasers grown on silicon will be presented. We consider the possibility of scalable, low size, weight, and power nanolasers grown on silicon enabled by quantum dWe review recent advances in the field of quantum dot lasers on silicon. A summary of device performance, reliability, and comparison with similar quantum well lasers grown on silicon will be presented. We consider the possibility of scalable, low size, weight, and power nanolasers grown on silicon enabled by quantum dot active regions for future short-reach silicon photonics interconnects..
Photonics Research
- Publication Date: Jan. 06, 2016
- Vol. 3, Issue 5, B1 (2015)
Introduction for the Integrated Photonics: Challenges and Perspectives feature
Daoxin Dai, Di Liang, and Liu Liu
We give an introduction for the background and motivation of the Integrated Photonics: Challenges and Perspectives feature. A very brief summary for the five invited review articles collected in this feature issue is also given.We give an introduction for the background and motivation of the Integrated Photonics: Challenges and Perspectives feature. A very brief summary for the five invited review articles collected in this feature issue is also given..
Photonics Research
- Publication Date: Oct. 01, 2015
- Vol. 3, Issue 5, IP1 (2015)
Silicon and hybrid silicon photonic devices for intra-datacenter applications: state of the art and perspectives [Invited]
Yu Li, Yu Zhang, Lei Zhang, and Andrew W. Poon
We review the state of the art and our perspectives on silicon and hybrid silicon photonic devices for optical interconnects in datacenters. After a brief discussion of the key requirements for intra-datacenter optical interconnects, we propose a wavelength-division-multiplexing (WDM)-based optical interconnect for intWe review the state of the art and our perspectives on silicon and hybrid silicon photonic devices for optical interconnects in datacenters. After a brief discussion of the key requirements for intra-datacenter optical interconnects, we propose a wavelength-division-multiplexing (WDM)-based optical interconnect for intra-datacenter applications. Following our proposed interconnects configuration, the bulk of the review emphasizes recent developments concerning on-chip hybrid silicon microlasers and WDM transmitters, and silicon photonic switch fabrics for intra-datacenters. For hybrid silicon microlasers andWDM transmitters, we outline the remaining challenges and key issues toward realizing low power consumption, direct modulation, and integration of multiwavelength microlaser arrays. For silicon photonic switch fabrics, we review various topologies and configurations of high-port-count N-by-N switch fabrics using Mach–Zehnder interferometers and microring resonators as switch elements, and discuss their prospects toward practical implementations with active reconfiguration. For the microring-based switch fabrics, we review recent developments of active stabilization schemes at the subsystem level. Last, we outline several large challenges and problems for silicon and hybrid silicon photonics to meet for intra-datacenter applications and propose potential solutions.Optoelectronics;Diode laser arrays;Diode lasers;Laser resonators.
Photonics Research
- Publication Date: Jul. 31, 2015
- Vol. 3, Issue 5, B10 (2015)
Lowering the energy consumption in silicon photonic devices and systems [Invited]
Zhiping Zhou, Bing Yin, Qingzhong Deng, Xinbai Li, and Jishi Cui
We review current silicon photonic devices and their performance in connection with energy consumption. Four critical issues are identified to lower energy consumption in devices and systems: reducing the influence of the thermo-optic effect, increasing the wall-plug efficiency of lasers on silicon, optimizing energy pWe review current silicon photonic devices and their performance in connection with energy consumption. Four critical issues are identified to lower energy consumption in devices and systems: reducing the influence of the thermo-optic effect, increasing the wall-plug efficiency of lasers on silicon, optimizing energy performance of modulators, and enhancing the sensitivity of photodetectors. Major conclusions are (1) Mach–Zehnder interferometer-based devices can achieve athermal performance without any extra energy consumption while microrings do not have an efficient passive athermal solution; (2) while direct bonded III–V-based Si lasers can meet system power requirement for now, hetero-epitaxial grown III–V quantum dot lasers are competitive and may be a better option for the future; (3) resonant modulators, especially coupling modulators, are promising for low-energy consumption operation even when the power to stabilize their operation is included; (4) benefiting from high sensitivity and low cost, Ge/Si avalanche photodiode is the most promising photodetector and can be used to effectively reduce the optical link power budget. These analyses and solutions will contribute to further lowering energy consumption to meet aggressive energy demands in future systems..
Photonics Research
- Publication Date: Aug. 06, 2015
- Vol. 3, Issue 5, B28 (2015)
Silicon and silicon nitride photonic circuits for spectroscopic sensing on-a-chip [Invited]
Ananth Z. Subramanian, Eva Ryckeboer, Ashim Dhakal, Frédéric Peyskens... and Roel Baets|Show fewer author(s)
There is a rapidly growing demand to use silicon and silicon nitride (Si3N4) integrated photonics for sensing applications, ranging from refractive index to spectroscopic sensing. By making use of advanced CMOS technology, complex miniaturized circuits can be easily realized on a large scale and at a low cost covering There is a rapidly growing demand to use silicon and silicon nitride (Si3N4) integrated photonics for sensing applications, ranging from refractive index to spectroscopic sensing. By making use of advanced CMOS technology, complex miniaturized circuits can be easily realized on a large scale and at a low cost covering visible to mid-IR wavelengths. In this paper we present our recent work on the development of silicon and Si3N4-based photonic integrated circuits for various spectroscopic sensing applications. We report our findings on waveguide-based absorption, and Raman and surface enhanced Raman spectroscopy. Finally we report on-chip spectrometers and on-chip broadband light sources covering very near-IR to mid-IR wavelengths to realize fully integrated spectroscopic systems on a chip..
Photonics Research
- Publication Date: Aug. 28, 2015
- Vol. 3, Issue 5, B47 (2015)
InP photonic circuits using generic integration [Invited]
K. A. Williams, E. A. J. M. Bente, D. Heiss, Y. Jiao... and M. K. Smit|Show fewer author(s)
InP integrated photonics has become a critical enabler for modern telecommunications, and is poised to revolutionize data communications, precision metrology, spectrometry, and imaging. The possibility to integrate high-performance amplifiers, lasers, modulators, and detectors in combination with interferometers withinInP integrated photonics has become a critical enabler for modern telecommunications, and is poised to revolutionize data communications, precision metrology, spectrometry, and imaging. The possibility to integrate high-performance amplifiers, lasers, modulators, and detectors in combination with interferometers within one chip is enabling game-changing performance advances, energy savings, and cost reductions. Generic integration accelerates progress through the separation of applications from a common technology development. In this paper, we review the current status in InP integrated photonics and the efforts to integrate the next generation of high-performance functionality on a common substrate using the generic methodology..
Photonics Research
- Publication Date: Aug. 28, 2015
- Vol. 3, Issue 5, B60 (2015)
Laser Materials Processing
Laser-annealing-made amplified spontaneous emission of “giant” CdSe/CdS core/shell nanocrystals transferred from bulk-like shell to quantum-confined core
Chen Liao, Kai Fan, Ruilin Xu, Huichao Zhang... and Jiayu Zhang|Show fewer author(s)
“Giant” CdSe/CdS core/shell nanocrystals (NCs) were synthesized with thick CdS shell (15 monolayers), and the x-ray diffraction (XRD) measurement indicates there is a zinc blende phase in the thick CdS shell, whereas it transformed into wurtzite phase under 5 min radiation with a 400 nm, 594 μJ∕cm2 femtosecond (fs) las“Giant” CdSe/CdS core/shell nanocrystals (NCs) were synthesized with thick CdS shell (15 monolayers), and the x-ray diffraction (XRD) measurement indicates there is a zinc blende phase in the thick CdS shell, whereas it transformed into wurtzite phase under 5 min radiation with a 400 nm, 594 μJ∕cm2 femtosecond (fs) laser beam. The evolution of the NCs’ spontaneous emission under the fs laser radiation was recorded with a Hamamatsu streak camera. The as-synthesized NCs exhibit an amplified spontaneous emission (ASE) at 530 nm, which comes from a bulk-like CdS shell due to the interfacial potential barrier, which could slow down the relaxation of holes from the shell to the core. After being annealed by an fs laser, the ASE of the g-NCs is transferred from a bulk-like CdS shell to a quantum-confined CdSe core because the phase transformation determined with the XRD measurement could remove the interfacial barrier. Besides the ASE at 643 nm, two shorter-wavelength ASE peaks at 589 and 541 nm, corresponding to optical transitions of the second (1P) and third (1D) electron quantization shells of the CdSe core, also appear, thus indicating that Auger recombination is effectively suppressed.materials.
Photonics Research
- Publication Date: Aug. 07, 2015
- Vol. 3, Issue 5, 200 (2015)
Lasers and Laser Optics
73 nJ, 109 fs Yb-doped fiber laser at 19 MHz repetition rate in amplifier similariton regime
Yizhou Liu, Yifan Cui, Jian Zhang, Aimin Wang, and Zhigang Zhang
We report femtosecond pulse generation in an amplifier similariton oscillator and a prechirped fiber amplifier system. The final output power is 1.4 W, and the fundamental repetition rate is 19.1 MHz after a single state fiber amplifier. The pulsewidth is 109 fs.We report femtosecond pulse generation in an amplifier similariton oscillator and a prechirped fiber amplifier system. The final output power is 1.4 W, and the fundamental repetition rate is 19.1 MHz after a single state fiber amplifier. The pulsewidth is 109 fs..
Photonics Research
- Publication Date: Aug. 25, 2015
- Vol. 3, Issue 5, 248 (2015)
Compact Q-switched 2 μm Tm:GdVO4 laser with MoS2 absorber
Pingguang Ge, Jie Liu, Shouzhen Jiang, Yuanyuan Xu, and Baoyuan Man
A molybdenum disulfide (MoS2) saturable absorber was fabricated by thermally decomposing the ammonium thiomolybdate. By using the MoS2 absorber, a compact diode-pumped passively Q-switched Tm:GdVO4 laser has been demonstrated. A stable Q-switched laser with repetition rates from 25.58 to 48.09 kHz was achieved. MaximumA molybdenum disulfide (MoS2) saturable absorber was fabricated by thermally decomposing the ammonium thiomolybdate. By using the MoS2 absorber, a compact diode-pumped passively Q-switched Tm:GdVO4 laser has been demonstrated. A stable Q-switched laser with repetition rates from 25.58 to 48.09 kHz was achieved. Maximum average output power was 100 mW with the shortest pulse duration of 0.8 μs. Maximum pulse energy is 2.08 μJ at center of 1902 nm..
Photonics Research
- Publication Date: Aug. 31, 2015
- Vol. 3, Issue 5, 256 (2015)
Subnanosecond KTiOPO4 optical parametric oscillator intracavity pumped by a Kerr-lens, mode-locked YVO4/Nd:YVO4 laser coupled with an acousto-optic modulator
Hongwei Chu, Jia Zhao, Kejian Yang, Shengzhi Zhao... and Wenchao Qiao|Show fewer author(s)
A Kerr-lens, mode-locked YVO4∕Nd:YVO4 laser coupled with an acousto-optic modulator (AOM) Q-switching near 1064 nm was employed to pump an intracavity KTiOPO4 (KTP) optical parametric oscillator. A subnanosecond signal wave near 1572 nm with low repetition rate was realized. At an AOM repetition rate of 8 kHz, the maxiA Kerr-lens, mode-locked YVO4∕Nd:YVO4 laser coupled with an acousto-optic modulator (AOM) Q-switching near 1064 nm was employed to pump an intracavity KTiOPO4 (KTP) optical parametric oscillator. A subnanosecond signal wave near 1572 nm with low repetition rate was realized. At an AOM repetition rate of 8 kHz, the maximum output power was 165 mW. The highest average pulse energy, the shortest duration, and the highest peak power of a mode-locking signal pulse were estimated to be ～10.3 μJ, ～120 ps, and ～82 kW, respectively..
Photonics Research
- Publication Date: Jan. 06, 2016
- Vol. 3, Issue 5, 260 (2015)
Microscopy
Deep-UV fluorescence lifetime imaging microscopy
Christiaan J. de Jong, Alireza Lajevardipour, Mindaugas Gecevi?ius, Martynas Beresna... and Saulius Juodkazis|Show fewer author(s)
A novel fluorescence lifetime imaging microscopy (FLIM) working with deep UV 240–280 nm wavelength excitations has been developed. UV-FLIM is used for measurement of defect-related fluorescence and its changes upon annealing from femtosecond laser-induced modifications in fused silica. This FLIM technique can be used wA novel fluorescence lifetime imaging microscopy (FLIM) working with deep UV 240–280 nm wavelength excitations has been developed. UV-FLIM is used for measurement of defect-related fluorescence and its changes upon annealing from femtosecond laser-induced modifications in fused silica. This FLIM technique can be used with microfluidic and biosamples to characterize temporal characteristics of fluorescence upon UV excitation, a capability easily added to a standardmicroscope-based FLIM. UV-FLIMwas tested to show annealing of the defects induced by silica structuringwith ultrashort laser pulses. Frequency-domain fluorescencemeasurementswere converted into the time domain to extract long fluorescence lifetimes from defects in silica..
Photonics Research
- Publication Date: Sep. 28, 2015
- Vol. 3, Issue 5, 283 (2015)
Nonlinear Optics
Enhanced optical Kerr nonlinearity of MoS2 on silicon waveguides
Linghai Liu, Ke Xu, Xi Wan, Jianbin Xu... and Hon Ki Tsang|Show fewer author(s)
A quasi-two-dimensional layer of MoS2 was placed on top of a silicon optical waveguide to form a MoS2–silicon hybrid structure. Chirped pulse self-phase modulation measurements were carried out to determine the optical Kerr nonlinearity of the structure. The observed increase in the spectral broadening of the optical pA quasi-two-dimensional layer of MoS2 was placed on top of a silicon optical waveguide to form a MoS2–silicon hybrid structure. Chirped pulse self-phase modulation measurements were carried out to determine the optical Kerr nonlinearity of the structure. The observed increase in the spectral broadening of the optical pulses in the MoS2–silicon waveguide compared with the silicon waveguides indicated that the third-order nonlinear effect in MoS2 is about 2 orders of magnitude larger than that in silicon. The measurements show that MoS2 has an effective optical Kerr coefficient of about 1.1 × 10?16 m2∕W. This work reveals the potential application of MoS2 to enhance the nonlinearity of hybrid silicon optical devices..
Photonics Research
- Publication Date: Aug. 07, 2015
- Vol. 3, Issue 5, 206 (2015)
Multicolored sideband generation based on cascaded four-wave mixing with the assistance of spectral broadening in multiple thin plates
Peng Wang, Jun Liu, Fangjia Li, Xiong Shen, and Ruxin Li
The generation of multicolored sidebands with the spectrum from 377 to 970 nm in a 0.5-mm-thick N-WG280 Schott glass based on a cascaded four-wave mixing (CFWM) process is demonstrated. The experimental setup is compact and economical. A pulse with a broadened spectrum from 670 to 900 nm is generated by utilizing two 0The generation of multicolored sidebands with the spectrum from 377 to 970 nm in a 0.5-mm-thick N-WG280 Schott glass based on a cascaded four-wave mixing (CFWM) process is demonstrated. The experimental setup is compact and economical. A pulse with a broadened spectrum from 670 to 900 nm is generated by utilizing two 0.18-mm-thick fused silica glass plates and is used to provide two input beams for the CFWM process. The new frequency components generated from the self-phase modulation effect in the two thin glass plates contribute to the broadening of the total spectral range of the generated multicolored sidebands..
Photonics Research
- Publication Date: Aug. 13, 2015
- Vol. 3, Issue 5, 210 (2015)
Broadband ultrafast nonlinear optical response of few-layers graphene: toward the mid-infrared regime
Lili Miao, Yaqin Jiang, Shunbin Lu, Bingxin Shi... and Shuangchun Wen|Show fewer author(s)
Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by tGapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared (mid-IR) regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene (～10?7 cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics, potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices..
Photonics Research
- Publication Date: Aug. 13, 2015
- Vol. 3, Issue 5, 214 (2015)
Dynamics of lossless polarization attraction
Matteo Barozzi, and Armando Vannucci
We study a nonlinear lossless polarizer (NLP), a fiber-based device able to control the polarization of an optical signal while preserving its energy. The NLP exploits the lossless polarization attraction (LPA) generated by the Kerr interactions between the signal and a fully polarized continuous wave (CW) pump. By empWe study a nonlinear lossless polarizer (NLP), a fiber-based device able to control the polarization of an optical signal while preserving its energy. The NLP exploits the lossless polarization attraction (LPA) generated by the Kerr interactions between the signal and a fully polarized continuous wave (CW) pump. By employing a copropagating pump, we show that the effectiveness of LPA depends on the joint action of the Kerr nonlinearity and the mutual delay between signal and pump. We find the optimal pump wavelength placement and demonstrate that true LPA occurs only within a limited range of delay values. Thus, we explain why the copropagating NLP is more flexible and power efficient compared with the traditional counterpropagating NLP..
Photonics Research
- Publication Date: Aug. 21, 2015
- Vol. 3, Issue 5, 229 (2015)
Optical Devices
Arbitrary focusing lens by holographic metasurface
Rongzhen Li, Zhongyi Guo, Wei Wang, Jingran Zhang... and Jun Gao|Show fewer author(s)
In this paper, an ultrathin metalens has been proposed based on a holographic metasurface that consists of elongated apertures in 40 nm gold film, which exhibit intriguing properties such as on- and off-axis focusing and also can concentrate light into multiple, discrete spots for circularly polarized incident lights. In this paper, an ultrathin metalens has been proposed based on a holographic metasurface that consists of elongated apertures in 40 nm gold film, which exhibit intriguing properties such as on- and off-axis focusing and also can concentrate light into multiple, discrete spots for circularly polarized incident lights. First, the spatial transmission phase distributions of the designed metalens with arbitrary focusing can be obtained by computergenerated holography. Then, the discrete phase distributions can be continuously encoded by subwavelength nanoapertures with spatially varying orientations in gold film. The simulation results show that our designed metalens can work efficiently for different types of focusing. Finally, our metasurface shows superior broadband characteristics between 670 and 810 nm, and the corresponding focal lengths of the designed lenses also can be efficiently modulated with the incident lights at different wavelengths..
Photonics Research
- Publication Date: Aug. 31, 2015
- Vol. 3, Issue 5, 252 (2015)
Faraday anomalous dispersion optical filter at 133Cs weak 459 nm transition
Xiaobo Xue, Duo Pan, Xiaogang Zhang, Bin Luo... and Hong Guo|Show fewer author(s)
A 459 nm Faraday anomalous dispersion optical filter (FADOF) working at the side wings of the cesium 6S1∕2 → 7P1∕2 transition with weak oscillator strength is achieved. The transmittance of the higher side wing reaches 98% at a temperature of 179°C and magnetic field above 323 G. The experimental results coincide A 459 nm Faraday anomalous dispersion optical filter (FADOF) working at the side wings of the cesium 6S1∕2 → 7P1∕2 transition with weak oscillator strength is achieved. The transmittance of the higher side wing reaches 98% at a temperature of 179°C and magnetic field above 323 G. The experimental results coincide with the theoretical predictions in 1982 and 1995, which were not realized in experiments for over three decades. Due to its high transmittance, high accuracy, and narrow linewidth, the 459 nm FADOF can be applied in underwater optical communications, the building of active optical clocks, and laser frequency stabilization in active optical clocks..
Photonics Research
- Publication Date: Sep. 11, 2015
- Vol. 3, Issue 5, 275 (2015)
Optical Manipulation
Ray-optics model for optical force and torque on a spherical metal-coated Janus microparticle
Jing Liu, Chao Zhang, Yiwu Zong, Honglian Guo, and Zhi-Yuan Li
In this paper, we develop a theoretical method based on ray optics to calculate the optical force and torque on a metallo-dielectric Janus particle in an optical trap made from a tightly focused Gaussian beam. The Janus particle is a 2.8 μm diameter polystyrene sphere half-coated with gold thin film several nanometers In this paper, we develop a theoretical method based on ray optics to calculate the optical force and torque on a metallo-dielectric Janus particle in an optical trap made from a tightly focused Gaussian beam. The Janus particle is a 2.8 μm diameter polystyrene sphere half-coated with gold thin film several nanometers in thickness. The calculation result shows that the focused beam will push the Janus particle away from the center of the trap, and the equilibrium position of the Janus particle, where the optical force and torque are both zero, is located in a circular orbit surrounding the laser beam axis. The theoretical results are in good agreement qualitatively and quantitatively with our experimental observation. As the ray-optics model is simple in principle, user friendly in formalism, and cost effective in terms of computation resources and time compared with other usual rigorous electromagnetics approaches, the developed theoretical method can become an invaluable tool for understanding and designing ways to control the mechanical motion of complicated microscopic particles in various optical tweezers..
Photonics Research
- Publication Date: Sep. 11, 2015
- Vol. 3, Issue 5, 265 (2015)
Optical Resonators
Observation of high-Q optomechanical modes in the mounted silica microspheres
Zhen Shen, Zhong-Hao Zhou, Chang-Ling Zou, Fang-Wen Sun... and Guang-Can Guo|Show fewer author(s)
An efficient method to mount a coupled silica microsphere and tapered fiber system is proposed and demonstrated experimentally. For the purpose of optomechanical studies, high-quality-factor optical (Qo ～ 108) and mechanical modes (Qm ～ 0.87 × 104) are maintained after the mounting process. For the mounted microspAn efficient method to mount a coupled silica microsphere and tapered fiber system is proposed and demonstrated experimentally. For the purpose of optomechanical studies, high-quality-factor optical (Qo ～ 108) and mechanical modes (Qm ～ 0.87 × 104<)sup>) are maintained after the mounting process. For the mounted microsphere, the coupling system is more stable and compact and, thus, is beneficial for future studies and applications based on optomechanical interactions. Especially, the packaged optomechanical system, which is tested in a vacuum chamber, paves the way toward quantum optomechanics research in cryostat..
Photonics Research
- Publication Date: Aug. 24, 2015
- Vol. 3, Issue 5, 243 (2015)
High-Q silica microdisk optical resonators with large wedge angles on a silicon chip
Guanyu Li, Pei Liu, Xiaoshun Jiang, Chao Yang... and Min Xiao|Show fewer author(s)
We experimentally demonstrate high optical quality factor silica microdisk resonators on a silicon chip with large wedge angles by reactive ion etching. For 2-μm-thick microresonators, we have achieved wedge angles of 59°, 63°, 70°, and 79° with optical quality factors of 2.4 × 107, 8.1 × We experimentally demonstrate high optical quality factor silica microdisk resonators on a silicon chip with large wedge angles by reactive ion etching. For 2-μm-thick microresonators, we have achieved wedge angles of 59°, 63°, 70°, and 79° with optical quality factors of 2.4 × 107, 8.1 × 106, 5.9 × 106, and 7.4 × 106, respectively, from ～80 μmdiameter microresonators in the 1550 nm wavelength band. Also, for 1-μm-thick microresonators, we have obtained an optical quality factor of 7.3 × 106 with a wedge angle of 74°..
Photonics Research
- Publication Date: Jan. 06, 2016
- Vol. 3, Issue 5, 279 (2015)
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