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Articles 1 to 20 of 127 Next Page >>

January


Ptychographic ultrafast pulse reconstruction

  • Thomas Feurer, Dirk Spangenberg, Erich Rohwer, and Michael Bruegmann
  • received 11/21/2014; accepted 01/28/2015; posted 01/28/2015; Doc. ID 227132
  • [full text: PDF (539) KB)]
  • Abstract: We demonstrate a new ultrafast pulse reconstruction modality which is somewhat reminiscent of frequency resolved optical gating but uses a modified setup and a conceptually different reconstruction algorithm that is derived from ptychography. Even though it is a second order correlation scheme it shows no time ambiguity. Moreover, the number of spectra to record is considerably smaller than in most other related schemes which, together with a robust algorithm, leads to extremely fast convergence of the reconstruction.

Keywords (OCIS):

  • (320.2250) Ultrafast optics : Femtosecond phenomena
  • (320.7100) Ultrafast optics : Ultrafast measurements
  • (320.7160) Ultrafast optics : Ultrafast technology

CW-pumped wavelength conversion in low-loss silicon nitride waveguides

  • Clemens Krueckel, Victor Torres-Company, Peter Andrekson, Daryl Spencer, Jared Bauters, Martijn Heck, and John Bowers
  • received 12/16/2014; accepted 01/28/2015; posted 01/28/2015; Doc. ID 230655
  • [full text: PDF (473) KB)]
  • Abstract: In this paper we introduce a CMOS-compatible low-loss Si3N4 waveguide platform for nonlinear integrated optics. The waveguide has a moderate nonlinear coefficient of 285 /W/km, but the achieved propagation loss of only 0.06 dB/cm and the ability to handle high optical power facilitate an optimal waveguide length for wavelength conversion. We observe a constant quadratic dependence of the four-wave mixing (FWM) process on the continuous-wave (CW) pump when operating in the C-band. This indicates the waveguide has negligible high-power constraints owing to nonlinear losses. We achieve a conversion efficiency of -26.1 dB and idler power generation of -19.6 dBm. With these characteristics, we present for the first time to the best of our knowledge CW-pumped data conversion in a non-resonant Si3N4 waveguide.

Keywords (OCIS):

  • (130.3120) Integrated optics : Integrated optics devices
  • (190.4360) Nonlinear optics : Nonlinear optics, devices
  • (190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
  • (190.4390) Nonlinear optics : Nonlinear optics, integrated optics

Coupling-length phase matching for efficient third harmonic generation based on parallel coupled waveguides

  • Tianye Huang, Ping Shum, Michelle Shao, Timothy Lee, Zhifang Wu, Huizi Li, Tingting Wu, Meng Zhang, Xuan Dinh, and Gilberto Brambilla
  • received 01/07/2015; accepted 01/28/2015; posted 01/28/2015; Doc. ID 231772
  • [full text: PDF (2225) KB)]
  • Abstract: We study third harmonic generation (THG) in parallel coupled waveguides where spatial modulation of mode intensity can provide quasi-phase matching, named as coupling-length phase matching (CLPM), for efficient nonlinear frequency conversion. Different types of CLPM are investigated for THG, and it is found that two sets of CLPM conditions can be practically implemented with traditional waveguides. These two CLPM conditions are further investigated by considering nonlinear phase modulations, which can degrade the CLPM-based THG conversion. However, up to 45% efficiency is still possible in this scheme. The greatest significance of this approach is that the requirement of perfect phase matching in a single waveguide is no longer necessary, leading to an alternative waveguide design for THG.

Keywords (OCIS):

  • (190.2620) Nonlinear optics : Harmonic generation and mixing
  • (230.1150) Optical devices : All-optical devices
  • (190.4975) Nonlinear optics : Parametric processes
  • (250.4390) Optoelectronics : Nonlinear optics, integrated optics

Two mode injection locked FP laser receiver: A regenerator for long distance stable fiber delivery of radio frequency standards

  • Adonis Bogris, Dimitris Syvridis, and Thomas Nikas
  • received 12/22/2014; accepted 01/27/2015; posted 01/28/2015; Doc. ID 231204
  • [full text: PDF (434) KB)]
  • Abstract: We propose and experimentally validate a new robust and cost effective optical receiver – regenerator scheme for long distance microwave frequency standard dissemination, based on the properties of dual wavelength injection locked Fabry – Perot (FP) lasers. The regenerator FP laser is injection locked to one of its longitudinal modes by the incoming intensity modulated light carrying the microwave frequency standard. The light of a local CW laser is also injected in the regenerator FP, locking it to an adjacent mode. The dual injection locked laser reproduces the sinusoidal microwave frequency standard on both wavelengths. The regenerated original signal is transmitted to the next node, whilst the local wavelength is fed back to the previous node for phase error extraction and link compensation. Allan deviation measurements prove the robust performance of the proposed regenerator.

Keywords (OCIS):

  • (070.1170) Fourier optics and signal processing : Analog optical signal processing
  • (140.3520) Lasers and laser optics : Lasers, injection-locked
  • (060.5625) Fiber optics and optical communications : Radio frequency photonics

A digital image frequency spectrum method for analyzing speckle displacement in frequency domain

  • Yuming He, Hui Ge, Dabiao Liu, Bo Zhang, Lei Shen, and Song Guo
  • received 11/20/2014; accepted 01/27/2015; posted 01/28/2015; Doc. ID 227100
  • [full text: PDF (1800) KB)]
  • Abstract: A novel method called a digital image frequency spectrum (DIFS) method, used for analyzing digital speckle patterns with deformation in frequency domain is proposed. Two sub-images in the same position of two digital speckle patterns before and after deformation are used to form a Young’s fringe. And the parallel Young’s fringes pattern is automatically analyzed in frequency domain. We find that the displacement between the two sub-images can be directly obtained and a matching procedure used in the digital image correlation (DIC) is unnecessary when the DIFS is applied. Experimental results show that the novel method has a good accuracy in speckle displacement analysis and uses less time in computing integer-pixel displacement procedure.

Keywords (OCIS):

  • (070.4790) Fourier optics and signal processing : Spectrum analysis
  • (100.2000) Image processing : Digital image processing
  • (110.6150) Imaging systems : Speckle imaging
  • (120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure

1 J Operation of Monolithic Composite Ceramics with Yb:YAG Thin Layers – Multi-TRAM at 10 Hz and 100 Hz repetition rates

  • Martin Divoky, Shigeki Tokita, Junji Kawanaka, Sungin Hwang, Toshiyuki Kawashima, Hirofumi Kan, Tomas Mocek, and Antonio Lucianetti
  • received 11/06/2014; accepted 01/27/2015; posted 01/28/2015; Doc. ID 226398
  • [full text: PDF (1177) KB)]
  • Abstract: Experimental amplification of 10 ns pulses to energy of 1 J at repetition rate of 10-100 Hz in cryogenic multi-pass total-reflection active-mirror (TRAM) amplifier for the first time is reported. By using a monolithic multi-TRAM, which is a YAG ceramic composite with three thin Yb:YAG active layers, efficient energy extraction was achieved without parasitic lasing. Detailed measurement of output characteristics of the laser amplifier is presented; results are discussed and compared with numerical calculations.

Keywords (OCIS):

  • (140.0140) Lasers and laser optics : Lasers and laser optics
  • (140.3280) Lasers and laser optics : Laser amplifiers
  • (140.3460) Lasers and laser optics : Lasers
  • (140.3480) Lasers and laser optics : Lasers, diode-pumped
  • (140.3580) Lasers and laser optics : Lasers, solid-state
  • (140.3615) Lasers and laser optics : Lasers, ytterbium

Simultaneous photoacoustic microscopy of microvascular anatomy, oxygen saturation, and blood flow

  • Song Hu, Bo Ning, Matthew Kennedy, Adam Dixon, Naidi Sun, Rui Cao, Brian Soetikno, Ruimin Chen, Qifa Zhou, Kirk Shung, and John Hossack
  • received 12/03/2014; accepted 01/26/2015; posted 01/28/2015; Doc. ID 228595
  • [full text: PDF (4265) KB)]
  • Abstract: Capitalizing on the optical absorption of hemoglobin, photoacoustic microscopy (PAM) is uniquely capable of anatomical and functional characterization of the intact microcirculation in vivo. However, PAM of the metabolic rate of oxygen (MRO2) at the microscopic level remains an unmet challenge, mainly due to the lack of ability to simultaneously quantify microvascular diameter, oxygen saturation of hemoglobin (sO2), and blood flow at the same spatial scale. To fill this technical gap, we have developed a multi-parametric PAM platform. By analyzing both the sO2-encoded spectral dependence and flow-induced temporal decorrelation of photoacoustic signals generated by the raster-scanned mouse ear vasculature, we demonstrated—for the first time—simultaneous wide-field PAM of all three parameters down to the capillary level in vivo.

Keywords (OCIS):

  • (110.5120) Imaging systems : Photoacoustic imaging
  • (170.3880) Medical optics and biotechnology : Medical and biological imaging
  • (170.2655) Medical optics and biotechnology : Functional monitoring and imaging

Non-classical correlations between THz-bandwidth photons mediated by rotational quanta in hydrogen molecules

  • Philip Bustard, Paul Hockett, Michael Spanner, Jennifer Erskine, Duncan England, Rune Lausten, Joshua Nunn, and Benjamin Sussman
  • received 12/17/2014; accepted 01/26/2015; posted 01/28/2015; Doc. ID 230953
  • [full text: PDF (479) KB)]
  • Abstract: Quantum photonics offers much promise for the development of new technologies. The ability to control the interaction of light and matter at the level of single quantum excitations is a prerequisite for the construction of potentially powerful devices. Here we use the rotational levels of a room temperature ensemble of hydrogen molecules to couple two distinct optical modes at the single photon level using THz bandwidth femtosecond pulses. We observe photon correlations which violate a Cauchy-Schwarz inequality, thereby verifying the creation of a non-classical state. This work demonstrates the rich potential of molecules for use in ultrafast quantum photonic devices.

Keywords (OCIS):

  • (020.1670) Atomic and molecular physics : Coherent optical effects
  • (270.1670) Quantum optics : Coherent optical effects
  • (290.5860) Scattering : Scattering, Raman
  • (320.7110) Ultrafast optics : Ultrafast nonlinear optics

Integral decomposition and polarization properties of depolarizing Mueller matrices

  • Razvigor Ossikovski and Oriol Arteaga
  • received 12/18/2014; accepted 01/26/2015; posted 01/28/2015; Doc. ID 231041
  • [full text: PDF (551) KB)]
  • Abstract: We show that, by suitably defining the integral decomposition of a depolarizing Mueller matrix, it becomes possible to fully interpret the polarization response of the medium or structure under study in terms of mean values and variances - covariances of a set of six integral polarization properties. The latter appear as natural counterparts of the elementary (differential) polarization properties stemming from the differential decomposition of the Mueller matrix. However, unlike the differential decomposition, the integral one is always mathematically and physically realizable and is furthermore unambiguously defined inasmuch as a nondepolarizing estimate of the initial Mueller matrix is secured. The theoretical results are illustrated on an experimental example.

Keywords (OCIS):

  • (260.0260) Physical optics : Physical optics
  • (260.2130) Physical optics : Ellipsometry and polarimetry
  • (260.5430) Physical optics : Polarization

Experimental investigation of chirp properties induced by signal amplification in quantum-dot semiconductor optical amplifiers

  • Motoharu Matsuura, Hiroaki Ohta, and Ryota Seki
  • received 11/27/2014; accepted 01/25/2015; posted 01/28/2015; Doc. ID 228630
  • [full text: PDF (393) KB)]
  • Abstract: We experimentally show the dynamic frequency chirp properties induced by signal amplification in a quantum-dot semiconductor optical amplifier (QD-SOA) for the first time, to the best of our knowledge. We also compare the red and blue chirp peak values and temporal chirp changes while changing the gain and injected signal powers of the QD-SOA with those of a common SOA.

Keywords (OCIS):

  • (060.2330) Fiber optics and optical communications : Fiber optics communications
  • (060.2630) Fiber optics and optical communications : Frequency modulation
  • (230.5590) Optical devices : Quantum-well, -wire and -dot devices
  • (230.4480) Optical devices : Optical amplifiers

Markovian optical modes

  • Gabriel Martinez-Niconoff, Marco Antonio Rodriguez, Gerardo Gonzalez, Patricia Vara, Román Su\'arez-Xique Suárez-Xique, and Adrian Dominguez
  • received 11/11/2014; accepted 01/25/2015; posted 01/26/2015; Doc. ID 226548
  • [full text: PDF (439) KB)]
  • Abstract: We describe the transition of a set of optical modes following a Markov chain process, where the mean value of the amplitude converge to a new type of partially coherent mode, with the property that the coherence features are easily tunable with the parameters of the chain. The amplitude of the resulting mode depends on the probability transition of the chain. As a prototype we establish an analogy with gambler`s chain ruin, using as a basis for the vector space the Bessel modes of integer order. Computer simulations are shown.

Keywords (OCIS):

  • (030.0030) Coherence and statistical optics : Coherence and statistical optics
  • (030.4070) Coherence and statistical optics : Modes

Excitation of multiple resonances in 1D Anderson localized systems for efficient light amplification

  • Young Kim, Seung Ho Choi, and Kyung Min Byun
  • received 12/18/2014; accepted 01/24/2015; posted 01/28/2015; Doc. ID 230970
  • [full text: PDF (1564) KB)]
  • Abstract: Excitation of hybridized multiple resonances can be an effective route for coherent light generation in irregular 1D systems larger than the localization length of light. Necklace states are often considered to have nonlocalized states without high transmission. However, we propose that some hybridized/coupled states can have high resonant tunneling with spatially extended fields. If strong localization properties are preserved in hybridized resonances, the excitation of such states allows for deposition of the excitation energy deep into the structure and spatial overlap with local gain regions. This result could allow for better utilizing hybridized resonances in biological or natural photonic systems.

Keywords (OCIS):

  • (030.6600) Coherence and statistical optics : Statistical optics
  • (140.2050) Lasers and laser optics : Dye lasers
  • (140.4780) Lasers and laser optics : Optical resonators
  • (230.4170) Optical devices : Multilayers
  • (260.5740) Physical optics : Resonance
  • (290.4210) Scattering : Multiple scattering

Infrared hyperspectral upconversion imaging

  • Peter Tidemand-Lichtenberg, Louis Kehlet, Jeppe Dam, and Christian Pedersen
  • received 11/06/2014; accepted 01/24/2015; posted 01/28/2015; Doc. ID 226394
  • [full text: PDF (664) KB)]
  • Abstract: In this paper hyperspectral imaging in the mid-IR spectral region is demonstrated based on nonlinear frequency upconversion and subsequent imaging using a standard Si-based CCD camera. A series of upconverted images are acquired with different phase match conditions for the nonlinear frequency conversion process. From this, a sequence of monochromatic images in the 3.2 to 3.4 µm range is generated. The target used in the experiment consists of a standard USAF resolution target combined with a polystyrene film, resulting in both spatial and spectral information in the infrared signal.

Keywords (OCIS):

  • (110.3080) Imaging systems : Infrared imaging
  • (190.7220) Nonlinear optics : Upconversion
  • (300.6340) Spectroscopy : Spectroscopy, infrared
  • (110.4234) Imaging systems : Multispectral and hyperspectral imaging
  • (280.4788) Remote sensing and sensors : Optical sensing and sensors
  • (110.3010) Imaging systems : Image reconstruction techniques

Ultra-thin triple-layer Fabry-Perot/SPP aluminum absorber in visible and near-infrared region

  • Yang Yang Li and Shiwei Shu
  • received 09/12/2014; accepted 01/23/2015; posted 01/28/2015; Doc. ID 222830
  • [full text: PDF (448) KB)]
  • Abstract: We report a novel type of ultra-thin absorber that can achieve near perfect absorption in the visible and near-infrared regions by utilizing the Fabry-Perot and the surface plasmon polariton (SPP) effects. The absorber consists of an Al/dielectric/Al triple-layered structure with the top Al layer consisting of an array of holes. The absorption features can be easily controlled by tuning the structural parameters, particularly the porous features of the top Al layer. When the porous features in the top Al layer are significantly smaller than the wavelength, light absorption is enabled through the Fabry-Perot effect. On the other hand, when the porous features in the top layer are at the subwavelength scale, new absorption peaks emerge due to the SPP effect. Furthermore, when the top Al layer consists of an array of hollow rings, the electric field at the interface between the top Al layer and the middle dielectric layer is greatly enhanced due to the plasmonic effect, indicating that the ultra-thin absorber reported here may be suitable for novel applications, e.g., the surface-enhanced Raman spectroscopy (SERS) substrates

Keywords (OCIS):

  • (240.0310) Optics at surfaces : Thin films
  • (260.3160) Physical optics : Interference
  • (350.2450) Other areas of optics : Filters, absorption

Time-stretch high-speed microscopic imaging system based on temporally and spectrally shaped amplified spontaneous emission

  • Cheng Lei, Hongwei Chen, Fangjian Xing, Minghua Chen, Sigang Yang, and Shizhong Xie
  • received 11/26/2014; accepted 01/23/2015; posted 01/26/2015; Doc. ID 228618
  • [full text: PDF (1086) KB)]
  • Abstract: In this paper, a time-stretch high-speed microscopic imaging system based on temporally and spectrally shaped amplified spontaneous emission (ASE) is proposed and experimentally demonstrated. We significantly reduced the complexity and cost of the light source by applying ASE in the time-stretch microscopic imaging system. Furthermore, by slicing the spectrum of the ASE with a Fabry–Perot (F-P) filter, the random intensity vibration of filtered ASE can be significantly suppressed, which would notably simplify the image recovery process afterwards. The resolution of the proposed system is better than 35 μm and the effective 1-D scan rate could reach 50 MHz.

Keywords (OCIS):

  • (140.0140) Lasers and laser optics : Lasers and laser optics
  • (170.0110) Medical optics and biotechnology : Imaging systems
  • (260.2030) Physical optics : Dispersion

Proximity effect assisted absorption enhancement in thin film with locally clustered nanoholes

  • Xiaofeng Li, Shaolong Wu, Yaohui Zhan, and Cheng Zhang
  • received 12/08/2014; accepted 01/23/2015; posted 01/26/2015; Doc. ID 229342
  • [full text: PDF (590) KB)]
  • Abstract: We focus on the light-trapping characteristics of a thin film with locally clustered nanoholes, with considering that the clustering effect is usually encountered in preparing the nanostructures. Our full-wave finite-element simulation indicates that an intentionally introduced clustering effect could be employed for improving the light-trapping performance of the nanostructured thin film. For a 100-nm-thick amorphous silicon film, an optimal nanohole-clustering design is able to double the integrated optical absorption over solar spectrum, compared to the planar counterpart, as well as shows much improved optical performance than that of the unclustered setup. A further insight into the underlying physics explains the outstanding light-trapping capability in terms of the increased available modes, a stronger power coupling efficiency, a higher fraction of electric field concentrated in absorbable material, and a higher density of photon states arising from the nanhole-clustering configuration.

Keywords (OCIS):

  • (040.5350) Detectors : Photovoltaic
  • (310.6860) Thin films : Thin films, optical properties
  • (350.6050) Other areas of optics : Solar energy

Volcanic CO2 detection with a DFM/OPA-based lidar

  • Luca Fiorani, Simone Santoro, Stefano Parracino, Marcello Nuvoli, Carmine Minopoli, and Alessandro Aiuppa
  • received 12/17/2014; accepted 01/23/2015; posted 01/26/2015; Doc. ID 230650
  • [full text: PDF (524) KB)]
  • Abstract: The DFM/OPA-based lidar BILLI was used to investigate the volcanic plume released by the hydrothermal vent of Pisciarelli, in the Campi Flegrei volcano. BILLI remotely measured CO2 concentrations in cross sections of the near-vent plume using the differential absorption technique. To our knowledge, this is the first example of lidar-based measurement of volcanic CO2. The spatial resolution was 1.5 m and the temporal resolution 20 s.

Keywords (OCIS):

  • (010.1110) Atmospheric and oceanic optics : Aerosols
  • (010.3640) Atmospheric and oceanic optics : Lidar
  • (280.1910) Remote sensing and sensors : DIAL, differential absorption lidar
  • (010.1030) Atmospheric and oceanic optics : Absorption

574 nm – 647 nm wavelength tuning by second harmonic generation from diode-pumped PPKTP waveguides

  • Ksenia Fedorova, Grigorii Sokolovskii, Philip Battle, Daniil Livshits, and Edik Rafailov
  • received 12/22/2014; accepted 01/23/2015; posted 01/26/2015; Doc. ID 231250
  • [full text: PDF (2680) KB)]
  • Abstract: We present a compact all-room-temperature continuous wave laser source in the visible spectral region between 574 nm and 647 nm by frequency-doubling of a broadly tunable InAs/GaAs quantum-dot external-cavity diode laser in a periodically-poled potassium titanyl phosphate crystal containing three waveguides with different cross-sectional areas (4x4µm², 3x5µm² and 2x6µm²). The influence of a waveguide’s design on tunability, output power and mode distribution of second harmonic generated light, as well as possibilities to increase the conversion efficiency via an optimization of a waveguide’s cross-sectional area, was systematically investigated. A maximum output power of 12.04 mW with a conversion efficiency of 10.29% at 605.6 nm was demonstrated in the wider waveguide with the cross-sectional area of 4x4µm².

Keywords (OCIS):

  • (140.3600) Lasers and laser optics : Lasers, tunable
  • (140.7300) Lasers and laser optics : Visible lasers
  • (190.2620) Nonlinear optics : Harmonic generation and mixing
  • (190.4360) Nonlinear optics : Nonlinear optics, devices
  • (230.7370) Optical devices : Waveguides
  • (250.5960) Optoelectronics : Semiconductor lasers

Ultrastable fiber amplifier delivering 145 fs pulses with 6 μJ energy at 10 MHz repetition rate

  • Marcel Wunram, Patrick Storz, Daniele Brida, and Alfred Leitenstorfer
  • received 12/09/2014; accepted 01/22/2015; posted 01/23/2015; Doc. ID 229404
  • [full text: PDF (593) KB)]
  • Abstract: A high-power femtosecond Yb:fiber amplifier operating with exceptional noise performance and long-term stability is demonstrated. It generates a 10 MHz train of 145 fs pulses at 1.03 μm with peak powers above 36 MW. The system features a relative amplitude noise of 2.6·10^-8 Hz^-1/2 at 1 MHz and drifts of the 60 W average power below 0.3% over 72 hours of continuous operation. The passively phase-stable Er:fiber seed system provides ultrabroadband pulses that are synchronized at a repetition rate of 40 MHz. This combination aims at new schemes for sensitive experiments in ultrafast scientific applications.

Keywords (OCIS):

  • (060.2320) Fiber optics and optical communications : Fiber optics amplifiers and oscillators
  • (140.3280) Lasers and laser optics : Laser amplifiers
  • (140.7090) Lasers and laser optics : Ultrafast lasers

Internal gain in Er-doped As2S3 chalcogenide planar waveguides

  • Kunlun Yan, Khu Vu, and Stephen Madden
  • received 12/15/2014; accepted 01/22/2015; posted 01/23/2015; Doc. ID 230680
  • [full text: PDF (690) KB)]
  • Abstract: Low loss Erbium doped As2S3 planar waveguides are fabricated by cothermal evaporation and plasma etching. Internal gain in the telecommunications band is demonstrated for the first time in any chalcogenide glass, and additionally in a thin film planar waveguide amplifier configuration.

Keywords (OCIS):

  • (130.3060) Integrated optics : Infrared
  • (140.5680) Lasers and laser optics : Rare earth and transition metal solid-state lasers
  • (230.4480) Optical devices : Optical amplifiers

Articles 1 to 20 of 127 Next Page >>





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