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Coherence theory of a laser beam passing through a moving diffuser
Mon, 2013-06-03 02:00 — GuestGaoming Li, Yishen Qiu, Hui Li
Abstract: We present the general coherence theory for laser beams passing through a moving diffuser. The temporal coherence of laser beams passing through a moving diffuser depends on two characteristic temporal scales: the laser coherence time and the mean time it takes the diffuser to move past a ... [Opt. Express 21, 13032-13039 (2013)]
Dual-wavelength laser source for onboard atom interferometry
Tue, 2011-11-01 02:00 — GuestV. Ménoret, R. Geiger, G. Stern, N. Zahzam, B. Battelier, A. Bresson, A. Landragin, P. Bouyer
We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the ... [Opt. Lett. 36, 4128-4130 (2011)]
- 4 comments
- Feed: Optics Letters
- Original article
- 122104 reads
Single pulse coherence measurements in the water window at the free-electron laser FLASH
Mon, 2013-06-03 02:00 — GuestD. D. Mai, J. Hallmann, T. Reusch, M. Osterhoff, S. Düsterer, R. Treusch, A. Singer, M. Beckers, T. Gorniak, T. Senkbeil, R. Dronyak, J. Gulden, O. M. Yefanov, A. Al-Shemmary, A. Rosenhahn, A. P. Mancuso, I. A. Vartanyants, T. Salditt
The spatial coherence of free-electron laser radiation in the water window spectral range was studied, using the third harmonic (λ_3rd = 2.66 nm) of DESY’s Free-electron LASer in Hamburg (FLASH). Coherent single pulse diffraction patterns of ... [Opt. Express 21, 13005-13017 (2013)]
- 1 comment
- Feed: Optics Express
- Original article
- 1838 reads
Feature tracking for projection registration in laboratory-scale reflective tomography laser radar imaging
Fri, 2010-05-21 21:11 — GuestPublication year: 2010
Source: Optics Communications, In Press, Uncorrected Proof, Available online 21 May 2010
Xiaofeng, Jin , Jianfeng, Sun , Yi, Yan , Yu, Zhou , Liren, Liu
In range-resolved reflective tomography laser radar imaging system, for accurate image reconstruction, all projections must be aligned to the center of target rotation. Due to the unknown location of the axis of rotation and random target translation, the center of target rotation in each projection cannot be measured accurately and images reconstructed based on range-resolved projections without registration would be dislocated. Here, we apply a feature tracking method to align projections data for tomographic reconstruction in laboratory-scale laser radar imaging. The target was placed on a spin table with an unknown and fixed axis, and the oscillatory motion of the...
Limitations of synthetic aperture laser optical feedback imaging
Thu, 2012-11-01 02:00 — GuestWilfried Glastre, Olivier Jacquin, Olivier Hugon, Hugues Guillet de Chatellus, Eric Lacot
In this paper we study the origin and the effect of amplitude and phase noise on laser optical feedback imaging associated with a synthetic aperture (SA) imaging system. Amplitude noise corresponds to photon noise and acts as an additive noise; it can be reduced by increasing the global measurement ... [J. Opt. Soc. Am. A 29, 2247-2255 (2012)]
Influence of metal substrates on the detection of explosive residues with laser-induced breakdown spectroscopy
Fri, 2013-02-01 02:00 — GuestJennifer L. Gottfried
Laser-induced breakdown spectroscopy is a promising approach for explosive residue detection, but several limitations to its widespread use remain. One issue is that the emission spectra of the residues are dependent on the substrate composition because some of the substrate is usually entrained in ... [Appl. Opt. 52, B10-B19 (2013)]
- 4 comments
- Feed: Applied Optics
- Original article
- 31961 reads
Investigation on LD end-pumped passively Q-switched c-cut Nd: YVO_4 self-Raman laser
Mon, 2013-06-03 02:00 — GuestShuanghong Ding, Meiqin Wang, Shiwu Wang, Wenhui Zhang
The compact LD end-pumped passively Q-switched c-cut Nd:YVO_4/Cr^4+:YAG self-Raman laser is realized, and its output performance is investigated in detail. The maximum average output power at 1178nm is 800mW with the pulse repetition frequency of 44kHz and pulse width of 2.6ns, and the first Stokes ... [Opt. Express 21, 13052-13061 (2013)]
End-to-End Multicore Multimode Fiber Optic Link Operating up to 120 Gb/s
Wed, 2012-02-15 19:01 — GuestA full multicore fiber optic link is demonstrated, transmitting greater than 100 Gb/s through a single strand of multimode fiber for the first time. The fiber, which consists of seven graded-index multimode cores, is used to transmit up to 120 Gb/s over 100 m using a custom multicore-fiber interfacing transmitter and receiver. 2-D arrays of vertical-cavity surface-emitting lasers (VCSELs) and vertically illuminated photodiodes (PDs) are fabricated with a geometry corresponding to the outer six cores of the seven-core fiber, which is arranged in a hexagonal pattern. Both flip-chip and wire-bonding technologies are used to package the VCSEL and PD chips with multichannel transmitter and receiver integrated circuits. Amplitude and timing margins of the end-to-end signals are analyzed through bit-error-rate (BER) measurements. The effects of electrical and optical crosstalk are shown to result in negligible degradation to the BER performance.
Low Yield of Near-Zero-Momentum Electrons and Partial Atomic Stabilization in Strong-Field Tunneling Ionization
Mon, 2012-08-27 16:00 — GuestAuthor(s): Hong Liu, Yunquan Liu, Libin Fu, Guoguo Xin, Difa Ye, Jie Liu, X. T. He, Yudong Yang, Xianrong Liu, Yongkai Deng, Chengyin Wu, and Qihuang Gong
We measure photoelectron angular distributions of single ionization of krypton and xenon atoms by laser pulses at 1320 nm, 0.2–1.0×1014 W/cm2, and observe that the yield of near-zero-momentum electrons in the strong-field tunneling ionization regime is significantly suppressed. Semiclassical simula...
[Phys. Rev. Lett. 109, 093001] Published Mon Aug 27, 2012
Far-field interference from a sphere and its applications
Tue, 2012-05-01 02:00 — GuestJianmin Li, Ye Tian, Chongxiang Li
A theoretical model of far-field interference from a sphere has been established, and its applications have been investigated. When two coherent parallel laser beams shine on a smooth sphere surface from opposite directions, the reflected lights form interference fringes at far field. The fringes ... [Appl. Opt. 51, 2501-2504 (2012)]
- 1 comment
- Feed: Applied Optics
- Original article
- 2933 reads
Laser-induced microjet: wavelength and pulse duration effects on bubble and jet generation for drug injection
Fri, 2013-05-24 02:00 — GuestAbstract
The expansion of the laser-induced bubble is the main mechanism in the developed microjet injector. In this study, Nd:YAG and Er:YAG lasers are used as triggers of the bubble formation. The impact of the laser parameters on the bubble dynamics is studied and the performance of the injector is evaluated. We found that the main cause of the differences in the bubble behavior comes from the pulse duration and wavelength. For Nd:YAG laser, the pulse duration is very short relative to the bubble lifetime making the behavior of the bubble close to that of the cavitation bubble, while in Er:YAG case, the high absorption in the water and long pulse duration change the initial behavior of the bubble making it close to a vapor bubble. The contraction and subsequent rebound are typical for cavitation bubbles in both cases. The results show that the laser-induced microjet injector generates velocity which is sufficient for the drug delivery for both laser beams of different pulse duration.
Large optical gain AlGaN-delta-GaN quantum wells laser active regions in mid- and deep-ultraviolet spectral regimes
Thu, 2011-04-28 21:00 — GuestJing Zhang, Hongping Zhao, and Nelson Tansu
The gain characteristics of high Al-content AlGaN-delta-GaN quantum wells (QWs) are investigated for mid- and deep-ultraviolet (UV) lasers. The insertion of an ultrathin GaN layer in high Al-content AlGaN QWs leads to valence subbands rearrangement, which in turn results in large optical gain for mi ... [Appl. Phys. Lett. 98, 171111 (2011)] published Thu Apr 28, 2011.
Remembering the laser diode
Fri, 2012-11-30 02:00 — GuestNature Photonics 6, 795 (2012).
doi:10.1038/nphoton.2012.310
Fifty years ago, researchers at a handful of laboratories around the world were reporting lasing from the first semiconductor lasers. Our IT infrastructure today relies on their diligence and success.
Enhancement of third-harmonic emission from femtosecond laser filament screened partially by a thin fiber
Wed, 2010-03-24 07:00 — GuestZhe Zhang, Xin Lu, Yi Zhang, Mulin Zhou, Tingting Xi, Zhaohua Wang, Jie Zhang
The third-harmonic (TH) emission characteristics from femtosecond laser filament, the center of which is screened by a thin metallic fiber, are experimentally investigated. The intensity of the TH emission has been enhanced for 1 order of magnitude by comparing with the undisturbed filament. The ... [Opt. Lett. 35, 974-976 (2010)]
Low Earth orbit satellite-to-ground optical scintillation: comparison of experimental observations and theoretical predictions
Fri, 2011-07-01 02:00 — GuestHarold T. Yura, David A. Kozlowski
Scintillation measurements of a 1064?nm laser at a 5?kHz sampling rate were made by an optical ground station at the European Space Agency observatory in Tenerife, Spain while tracking a low Earth orbit satellite during the spring and summer of 2010. The scintillation index (SI), the variance of ... [Opt. Lett. 36, 2507-2509 (2011)]
Zero-lag synchronization and bubbling in delay-coupled lasers
Tue, 2012-02-21 17:00 — GuestAuthor(s): J. Tiana-Alsina, K. Hicke, X. Porte, M. C. Soriano, M. C. Torrent, J. Garcia-Ojalvo, and I. Fischer
We show experimentally that two semiconductor lasers mutually coupled via a passive relay fiber loop exhibit chaos synchronization at zero lag, and study how this synchronized regime is lost as the lasers’ pump currents are increased. We characterize the synchronization properties of the system with...
[Phys. Rev. E 85, 026209] Published Tue Feb 21, 2012
Estimating cutting front temperature difference in disk and CO2 laser beam fusion cutting
Fri, 2012-03-09 03:00 — GuestPublication year: 2012
Source:Optics & Laser Technology, Volume 44, Issue 5
L.D. Scintilla, L. Tricarico
Ciliary White Light: Optical Aspect of Ultrashort Laser Ablation on Transparent Dielectrics
Fri, 2013-03-01 17:00 — GuestAuthor(s): Yi Liu, Yohann Brelet, Zhanbing He, Linwei Yu, Sergey Mitryukovskiy, Aurélien Houard, Benjamin Forestier, Arnaud Couairon, and André Mysyrowicz
We report on a novel nonlinear optical phenomenon, coined as ciliary white light, during laser ablation of transparent dielectrics. It is observed in 14 different transparent materials including glasses, crystals, and polymers. This phenomenon is also universal with respect to laser polarization, pu...
[Phys. Rev. Lett. 110, 097601] Published Fri Mar 01, 2013
One-year clinical results of Er,Cr:YSGG laser application in addition to scaling and root planing in patients with early to moderate periodontitis
Mon, 2010-06-14 16:15 — Guest
depth between 3–6 mm were examined. For each participant, two treatment types were alternatively applied on the contralateral
quadrants: scaling and root planing (SRP) as control, and SRP followed by Er,Cr:YSGG laser application (SRP+laser), as a test
method. Five clinical parameters: plaque level, bleeding on probing, probing depth, gingival recession and clinical attachment
level were examined at baseline and at 2, 3, 6, 12 months after treatment. Of the total of 1,668 sites examined in all patients,
1,088 sites were found with a probing depth of 3–6 mm. In these sites, differences in clinical parameters between SRP and
SRP+laser-treated quadrants were analyzed, assuming the level of p < 0.05 as significant.
Recursion-relation analysis for optical pumping to polarize nuclei by a sequence of short laser pulses
Thu, 2011-09-01 02:00 — GuestTakashi Nakajima
We carry out the recursion-relation analysis for the optical pumping scheme to polarize nuclei by a sequence of short laser pulses and show that such analysis agrees very well with the numerical solution of density matrix equations. A small difference between the results obtained by the numerical ... [J. Opt. Soc. Am. B 28, 2123-2128 (2011)]
