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Now showing items 33 - 48 of 143

  • IMAGING DEVICE AND METHOD

    The resolution of conventional imaging devices is restricted by the diffraction limit. 'Perfect' imaging devices which can achieve a resolution beyond the diffraction limit have been considered impossible to implement. However, the present disclosure provides an imaging device which can achieve improved resolution beyond the diffraction limit and which can be implemented in practice. Said imaging device comprises: a. a lens having a refractive index that varies according to a predetermined refractive index profile; b. a source; c. an outlet for decoupling waves from the device; and d.a reflector provided around the lens, the source and the outlet, wherein the reflector and the refractive index profile of the lens are together arranged to direct waves transmitted in any of a plurality of directions from the source to the outlet.
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  • HIGH-SPEED OPTICAL SAMPLING BY TEMPORAL STRETCHING USING FOUR-WAVE MIXING

    Systems and methods are provided for ultrafast optical waveform sampling based on temporal stretching of an input signal waveform. Temporal stretching is performed using a time lens based on four-wave mixing in a nonlinear medium. The signal is passed through an input dispersive element. The dispersed signal is sent into the time lens, which comprises a chirped pump pulse and a nonlinear medium. The chirped pump pulse is combined with the signal. The four-wave mixing process occurs in the nonlinear device or medium, which results in the generation of a signal at a new optical frequency (idler). The idler is spectrally separated from the signal and pump pulse using a bandpass filter and sent into an output dispersive element. The output dispersive element is longer than the input dispersive element and the temporal stretching factor is given by the ratio between the dispersions of these two elements.
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  • UWB monocycle pulse generation using two-photon absorption in a silicon waveguide

    Yue, Yang   Huang, Hao   Zhang, Lin   Wang, Jian   Yang, Jeng-Yuan   Yilmaz, Omer F.   Levy, Jacob S.   Lipson, Michal   Willner, Alan E.  

    We propose and experimentally demonstrate ultrawideband monocycle pulse generation using nondegenerate two-photon absorption in a silicon waveguide. The free-carrier absorption induced pulse tail at the rising edge of inverted probe pulse is largely compensated by the overlapped pump pulse and results in a symmetric negative monocycle pulse. A 143 ps Gaussian monocycle pulse is successfully obtained with a 131.7% fractional 10 dB bandwidth using a 68 ps pulsed pump. The 10 dB bandwidth and center frequency of the RF spectrum for the generated monocycle pulse can be largely tuned using an optical delay line. An operational bandwidth of 30 nm is demonstrated experimentally with stable performance, and larger optical bandwidth is expected. (C) 2012 Optical Society of America
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  • CMOS-compatible athermal silicon microring resonators.

    Guha, Biswajeet   Kyotoku, Bernardo B C   Lipson, Michal  

    We propose a new class of resonant silicon optical devices, consisting of a ring resonator coupled to a Mach-Zehnder interferometer, which is passively temperature compensated by tailoring the optical mode confinement in the waveguides. We demonstrate operation of the device over a wide temperature range of 80 degrees. The fundamental principle behind this work can be extended to other photonic devices based on resonators such as modulators, routers, switches and filters.
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  • Sub-nm resolution cavity enhanced microspectrometer

    Kyotoku, Bernardo B. C.   Chen, Long   Lipson, Michal  

    A novel on-chip spectrometer device using combined functionalities of a micro-ring resonator and a planar diffraction grating is proposed. We investigate the performance of this architecture by implementing it in a silicon-on-insulator platform. We experimentally demonstrate such a device with 100 channels, 0.1 nm channel spacing and a channel crosstalk less than -10 dB. The entire device occupies an area of less than 2 mm(2). Based on our initial results we envision that this device enables the possibility of the realization of low-cost and high-resolution ultra-compact spectroscopy. (C) 2009 Optical Society of America
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  • MICROFLUIDIC CHIP HAVING ON-CHIP ELECTRICALLY TUNABLE HIGH-THROUGHPUT NANOPHOTONIC TRAP

    In one implementation, a microfluidic device based on optical trapping of particles is disclosed to include a substrate structured to include a fluidic channel which can carry a fluid having particles; and an optical waveguide loop formed on the substrate to include one or more waveguide sections that reside within the fluidic channel, an input optical port for the optical waveguide to receive an input optical beam, and an optical power splitter coupled to the optical waveguide loop to split the received input optical beam into two counter- propagating optical beams that prorogate in the optical waveguide loop in opposite directions and interfere with each other to form standing optical waves in at least the one or more waveguide sections that reside within the fluidic channel to optically trap particles at or near a surface of the one or more waveguide sections that reside within the fluidic channel. This device further includes an electrically controllable phase control device formed on the substrate and coupled to a location of the optical waveguide loop and operable to control an optical delay experienced by guided light at the coupled location, wherein the electrically controllable phase control device is configured to respond to an electrical control signal to adjust an amount of the optical delay at the coupled location to cause a shift in locations of nodes of each optical standing wave to change trapping locations of the trapped particles in the fluidic channel.
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  • Reconfigurable nanophotonic silicon probes for sub-millisecond deep-brain optical stimulation

    Mohanty, Aseema   Li, Qian   Tadayon, Mohammad Amin   Roberts, Samantha P.   Bhatt, Gaurang R.   Shim, Euijae   Ji, Xingchen   Cardenas, Jaime   Miller, Steven A.   Kepecs, Adam   Lipson, Michal  

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  • OPTICAL FORCE BASED BIOMOLECULAR ANALYSIS IN SLOT WAVEGUIDES

    An architecture for the handling and transport of nanoscopic matter in lab on a chip devices using optical forces. A slot waveguide is used to focus and harness optical energy to trap and transport nanoscale objects. The slot waveguide is a unique structure that has several advantageous features, such as high optical confinement, and enables nanoparticles to interact fully with a propagating optical mode.
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  • Broadband Operation of Nanophotonic Router for Silicon Photonic Networks-on-Chip

    Biberman, Aleksandr   Lee, Benjamin G.   Sherwood-Droz, Nicolas   Lipson, Michal   Bergman, Keren  

    A nonblocking four-port bidirectional multiwave-length message router for use in photonic network-on-chip (NoC) architectures implementing two-dimensional mesh or torus topologies is fully characterized with bit-error-rate measurements and eye diagrams using three wavelength-parallel 10-Gb/s channels. The experiments demonstrate the feasibility of using this advanced switching subsystem within dynamically routed multiwave-length photonic NoCs.
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  • OPTOMECHANICAL OSCILLATOR NETWORK, CONTROL AND SYNCHRONIZATION METHODS, AND APPLICATIONS

    A synchronizable optomechanical oscillator (OMO) network including at least two dissimilar silicon nitride (Si3N4) optomechanical resonators that can be excited to evolve into self-sustaining optomechanical oscillators (OMOs) coupled only through an optical radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states.
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  • On-chip supercontinuum optical trapping and resonance excitation of microspheres.

    Nitkowski, Arthur   Gondarenko, Alexander   Lipson, Michal  

    We demonstrate the simultaneous optical manipulation and analysis of microscale particles in a microfluidic channel. Whispering gallery modes (WGMs) in dielectric microspheres are excited using the evanescent field from a silicon nitride waveguide. A supercontinuum source is used to both trap the microspheres to the surface of the waveguide and excite their resonant modes. All measurements are in plane, thus providing an integrated optofluidic platform for lab-on-a-chip biosensing applications.
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  • High-Speed 2 x 2 Switch for Multiwavelength Silicon-Photonic Networks-On-Chip

    Lee, Benjamin G.   Biberman, Aleksandr   Sherwood-Droz, Nicolas   Poitras, Carl B.   Lipson, Michal   Bergman, Keren  

    We report the fabrication and experimental verification of a multiwavelength high-speed 2 x 2 silicon photonic switch for ultrahigh-bandwidth message routing in optical on-chip networks. The structure employs only two microring resonators in order to implement the bar and cross states of the switch. These states are toggled using an optical pump at 1.5-mu m wavelengths in-plane with the waveguide devices, though electronic, rather than optical, control schemes are envisioned for more complex systems built from these devices. Experiments characterize bit-error-rate performance in the bar and cross states during static and dynamic operation. The all-optical demonstration exhibits the ability of the switch to implement ultra-short transition times (<2ns), high extinction ratios (>10 dB), and lowpower penalties (dB) at a data rate of 10 Gb/s. Further performance improvements are expected by using electronic carrier injection via p-i-n diodes surrounding the ring waveguides. The 2 x 2 switching functionality facilitates the design of more complex routing structures, allowing the implementation of high-functionality integrated optical networ ks.
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  • Low modal volume dipole-like dielectric slab resonator

    Gondarenko, Alexander   Lipson, Michal  

    We propose a novel geometry in a silicon planar resonator with an ultra-small modal volume of 0.01(lambda/2n)(3). The geometry induces strong electric field discontinuities to decrease the modal volume of the cavity below 1(lambda/2n)(3) The proposed structure and other common resonators such as 1D and 2D photonic crystal resonators are compared for tradeoffs in confinement and quality factors. (C) 2008 Optical Society of America
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  • Nonlinear optics in photonic nanowires RID E-8011-2010 RID E-8009-2010

    Foster, Mark A.   Turner, Amy C.   Lipson, Michal   Gaeta, Alexander L.  

    We review recent research on nonlinear optical interactions in waveguides with sub-micron transverse dimensions, which are termed photonic nanowires. Such nanowaveguides, fabricated from glasses or semiconductors, provide the maximal confinement of light for index guiding structures enabling large enhancement of nonlinear interactions and group-velocity dispersion engineering. The combination of these two properties make photonic nanowires ideally suited for many nonlinear optical applications including the generation of single-cycle pulses and optical processing with sub-mW powers. (C) 2008 Optical Society of America.
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  • On-chip gas detection in silicon optical microcavities

    Robinson, Jacob T.   Chen, Long   Lipson, Michal  

    We demonstrate a chip-scale photonic system for the room-temperature detection of gas composition and pressure using a slotted silicon microring resonator. We measure shifts in the resonance wavelength due to the presence and pressure of acetylene gas and resolve differences in the refractive index as small as 10(-4) in the near-IR. The observed sensitivity of this device ( enhanced due to the slot-waveguide geometry) agrees with the expected value of 490 nm/refractive index unit. (c) 2008 Optical Society of America.
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  • Tunable superluminal propagation on a silicon microchip RID A-7548-2010

    Manipatruni, Sasikanth   Dong, Po   Xu, Qianfan   Lipson, Michal  

    We demonstrate tunable superluminal propagation in a silicon microphotonic device in a solid-state room-temperature device of tens of micrometers in dimension allowing easy integration with high-bandwidth room-temperature systems. We achieve tunable negative delays up to 85 ps and effective group indices tunable between -1158 and -312. (C) 2008 Optical Society of America
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