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Noise induced

Annegret Meermeier, Svenja Gremmler, Kerstin Richert, Til Eckermann, Markus Lappe
Saccadic adaptation is an oculomotor learning process that maintains the accuracy of eye movements to ensure effective perception of the environment. Although saccadic adaptation is commonly considered an automatic and low-level motor calibration in the cerebellum, we recently found that strength of adaptation is influenced by the visual content of the target: pictures of humans produced stronger adaptation than noise stimuli. This suggests that meaningful images may be considered rewarding or valuable in oculomotor learning...
October 1, 2017: Journal of Vision
Vincent Nadon, Annelies Bockstael, Dick Botteldooren, Jérémie Voix
Purpose: In spite of all the efforts to implement workplace hearing conservation programs, noise-induced hearing loss remains the leading cause of disability for North American workers. Nonetheless, an individual's susceptibility to noise-induced hearing loss can be estimated by monitoring changes in hearing status in relation to the level of ambient noise exposure. The purpose of this study was to validate an approach that could improve workplace hearing conservation practices. The approach was developed using a portable and robust system designed for noisy environments and consisted of taking continuous measurements with high temporal resolution of the health status of the inner ear using otoacoustic emissions (OAEs)...
October 12, 2017: American Journal of Audiology
H Ahmad, A S Sharbirin, M Z Samion, M F Ismail
A compact all-fiber multimode interferometer (MMI) designed to produce a switchable multi-wavelength thulium-doped fiber laser (TDFL) is proposed and demonstrated. The TDFL fiber ring cavity employs a 60-cm-long multimode fiber into the cavity to induce multimode interference and provide intensity-dependent loss in order to generate a multi-wavelength output. The suppression of mode competition and the overall stability of the TDFL are further improved by exploiting the filtering capability of a Sagnac loop...
July 20, 2017: Applied Optics
Zhengqian Luo, Runhua Yang, Tuanjie Du, Qiujun Ruan, Weiwei Li, Nan Chen
In this paper, we report the intermode beating mode-locking of a 2  μm Tm(3+)-doped fiber laser (TDFL) pumped by a 1565 nm continuous-wave multi-longitudinal-mode laser. Because strong intermode beating of the 1565 nm pump source induces the periodic modulation of 2 μm intracavity power, stable mode-locking of the TDFL is successfully established by precisely matching the 2 μm cavity frequency with the intermode-beating frequency of the 1565 nm pump source. The mode-locked laser, without requiring any specific mode-locking element, can stably emit the rectangular nanosecond pulses...
August 1, 2017: Applied Optics
Hangzhou Wang, Liwen Nan, Hui Huang, Ping Yang, Hong Song, Jiwan Han, Yuanqian Wu, Tingting Yan, Zhuoli Yuan, Ying Chen
Adaptive measurement is a major concern when using miniature spectrometers in extreme environments, especially when the ambient temperatures and incident light intensities vary greatly. In this study, parameters, including the signal output and the relevant noise and signal-to-noise ratio (SNR) of a fiber optic spectrometry system composed of a photodiode array miniature spectrometer and external driver electronics were examined at multiple integration times from -50°C to 30°C, well below the specified operating temperature of this spectrometer...
October 1, 2017: Applied Optics
Boyu Xu, Changqiao Liu, Xiaofeng Jin, Xiangdong Jin, Xianbin Yu, Hao Chi, Shilie Zheng, Xianmin Zhang
In this paper, the frequency-dependent noise figure of a continuous photonic time-stretch system is theoretically analyzed and experimentally demonstrated. Mathematic analysis discloses that the frequency-dependent noise figure in the continuous photonic time-stretch system is mainly owing to the dispersion-induced phase shift in the link. In the experiment, a completely continuous signal is reconstructed with time-interleaved joining of four sections of time-stretched signals from optical wavelength-division de-multiplexing channels...
October 10, 2017: Applied Optics
Xueliang Li, Tianwen Geng, Shuang Ma, Yatian Li, Shijie Gao, Zhiyong Wu
The performance of coherent free-space optical (CFSO) communication with phase modulation is limited by both phase fluctuations and intensity scintillations induced by atmospheric turbulence. To improve the system performance, one effective way is to use digital phase estimation. In this paper, a CFSO communication system with quadrature phase-shift keying modulation is studied. With consideration of the effects of log-normal amplitude fluctuations and Gauss phase fluctuations, a two-stage Mth power carrier phase estimation (CPE) scheme is proposed...
June 1, 2017: Applied Optics
Tim Stangner, Hanqing Zhang, Tobias Dahlberg, Krister Wiklund, Magnus Andersson
Wide field-of-view imaging of fast processes in a microscope requires high light intensities motivating the use of lasers as light sources. However, due to their long spatial coherence length, lasers are inappropriate for such applications, as they produce coherent noise and parasitic reflections, such as speckle, degrading image quality. Therefore, we provide a step-by-step guide for constructing a speckle-free and high-contrast laser illumination setup using a rotating ground glass diffuser driven by a stepper motor...
July 1, 2017: Applied Optics
Scott Davies, Nicole Haddad, Jenny Q Ouyang
A major challenge in urban ecology is to identify the environmental factors responsible for phenotypic differences between urban and rural individuals. However, the intercorrelation between the factors that characterize urban environments, combined with a lack of experimental manipulations of these factors in both urban and rural areas, hinder efforts to identify which aspects of urban environments are responsible for phenotypic differences. Among the factors modified by urbanization, anthropogenic sound, particularly traffic noise, is especially detrimental to animals...
October 2017: Biology Letters
Franz R Villaruel, Franca Lacroix, Christian Sanio, Daniel W Sparks, C Andrew Chapman, Nadia Chaudhri
The infralimbic medial prefrontal cortex (IL) is important for suppressing learned behavior after extinction, but whether this function extends to responses acquired through appetitive Pavlovian conditioning is unclear. We trained male, Long-Evans rats to associate a white-noise conditional stimulus (CS; 10 s; 14 presentations per session) with 10% liquid sucrose (0.2 mL per CS presentation), and recorded entries into the fluid port during the CS. The CS was presented without sucrose in subsequent extinction and test sessions...
October 17, 2017: Cerebral Cortex
Remzi Dogan, Alev Pektas Sjostrand, Alper Yenıgun, Ersin Karatas, Abdurrahim Kocyigit, Orhan Ozturan
OBJECTIVE: The objective of this study was to investigate the influence of Ginkgo Biloba in early treatment of noise induced hearing loss on expression of IL-6, IL-1 Beta, TNF-alfa, HSP-70, HSF-1 and COX-2 in the rat cochlea. METHODS: Thirty two female rats were randomly divided into four groups (Acoustic Trauma, Ginkgo Biloba, Acoustic Trauma+Ginkgo Biloba, Non Treatment). Auditory brainstem response (ABR) was applied in all the groups. At the end of the study, IL-1Beta, IL-6, TNF-alpha, HSP-70, HSF-1 and COX-2 were studied in cochlear tissue with ELISA and Western blot analysis...
October 14, 2017: Auris, Nasus, Larynx
Xin Wen, Yashuai Han, Jinyu Liu, Jun He, Junmin Wang
A 2.8-dB polarization squeezing of the Stokes operatorS^2for the rubidium D1 line (795 nm) is achieved, with the lowest squeezing band at an audio frequency of 2.6 kHz. It is synthetized by a bright coherent beam and a squeezed vacuum, which are orthogonally polarized and share same frequency. Two methods are applied to support the optical parametric oscillator: an orthogonally-polarized locking beam that precludes residual unwanted interference and quantum noise locking method that locks the squeezing phase...
August 21, 2017: Optics Express
Chong Wang, Haiyun Xia, Mingjia Shangguan, Yunbin Wu, Lu Wang, Lijie Zhao, Jiawei Qiu, Renjun Zhang
Atmospheric depolarization ratio and wind velocity are measured simultaneously by a single versatile coherent Doppler lidar (CDL). Backscattering components at parallel and perpendicular polarization states are obtained by using a single balanced detector, adopting time-division multiplexing technique. Thus systematic error induced by the non-uniform response of different detectors in traditional lidars is avoided. The operation mode of the instrument can be switched from polarization CDL to traditional CDL by the user depending on atmospheric conditions and desired performance...
August 21, 2017: Optics Express
Yan Zhang, Ping Wang, Lixin Guo, Wei Wang, Hongxin Tian
The average bit error rate (ABER) performance of an orbital angular momentum (OAM) multiplexing-based free-space optical (FSO) system with multiple-input multiple-output (MIMO) architecture has been investigated over atmospheric turbulence considering channel estimation and space-time coding. The impact of different types of space-time coding, modulation orders, turbulence strengths, receive antenna numbers on the transmission performance of this OAM-FSO system is also taken into account. On the basis of the proposed system model, the analytical expressions of the received signals carried by the k-th OAM mode of the n-th receive antenna for the vertical bell labs layered space-time (V-Blast) and space-time block codes (STBC) are derived, respectively...
August 21, 2017: Optics Express
Xi Chen, Zhenhua Feng, Ming Tang, Songnian Fu, Deming Liu
As a promising solution for short-to-medium transmission systems, direct detection optical orthogonal frequency division multiplexing (DDO-OFDM) or discrete multi-tone (DMT) has been intensively investigated in last decade. Benefitting from the advantages of peak-to-average power (PAPR) reduction and signal-to-noise ratio (SNR) equalization, precoding techniques are widely applied to enhance the performance of DDO-OFDM systems. However, the conventional method of partitioning precoding sets limits the ability of precoding schemes to optimize the SNR variation and the allocation of modulation formats...
September 18, 2017: Optics Express
Avi Motil, Roy Davidi, Raanan Hadar, Moshe Tur
It has been recently shown that in stimulated Brillouin amplification (pulsed pump & CW probe) the line-shape of the normalized logarithmic Brillouin Gain Spectrum (BGS) broadens with increasing gain. Most pronounced for short pump pulses, a linewidth increase of ~3 MHz (~1.5 MHz) per dB of additional gain was observed for a pump pulse width of 15 ns (30 ns), respectively. This gain-dependency of the shape of the BGS compromises the accuracy of the otherwise attractive, highly dynamic and distributed slope-assisted BOTDA techniques, where measurand-induced gain variations of a single probe, are converted to strain/temperature values through a calibration factor that depends on the line-shape of the BGS...
September 18, 2017: Optics Express
Zhaoyang Li, Shigeki Tokita, Satoshi Matsuo, Keiichi Sueda, Takashi Kurita, Toshiyuki Kawasima, Noriaki Miyanaga
Herein, a theory for modeling the problem of scattering pulse-induced temporal contrast degradation in chirped-pulse amplification (CPA) lasers is introduced. Using this model, the temporal evolutions of the scattering and signal pulses were simulated, the temporal contrasts for different cases were compared, and finally the theoretical prediction was verified by an experimental demonstration. The result shows that the picosecond and the nanosecond temporal contrast is mainly determined by the scattering pulses generated in the stretcher and the compressor, respectively...
September 4, 2017: Optics Express
Lan Luo, Xiaodong Qiu, Linguo Xie, Xiong Liu, Zhaoxue Li, Zhiyou Zhang, Jinglei Du
In this paper, a method to improve the precision of prism-coupler-based surface plasmon resonance (SPR) sensors using weak-value amplification (WVA) is presented. A general theory model to describe the post-selected SPR sensing system is established and the polarization-dependent amplitude and phase evolutions induced by the SPR are regarded as the weak interactions in the WVA formalism. As a consequence of WVA, the detected signal can be enhanced with respect to the technical noise which is dependent on the post-selected light intensity...
September 4, 2017: Optics Express
Xin Fu, Ping Lu, Wenjun Ni, Hao Liao, Deming Liu, Jiangshan Zhang
A demodulation method for interferometric fiber sensors (IFSs) is proposed in this article. The phase variation induced by the measurands can be estimated by calculating the Fourier phase at the intrinsic spatial frequencies of the fiber sensor. Theoretical analysis of the demodulation method is discussed in detail. Numerical simulations are put forward to demonstrate the consistency of the demodulation results under different wavelength sampling interval and noise level, showing a better stability compared with the conventional peak wavelength tracking technique...
September 4, 2017: Optics Express
Wenhai Yang, Xiaoli Jin, Xudong Yu, Yaohui Zheng, Kunchi Peng
We investigate the dependence of the measured squeezing level on the local oscillator (LO) intensity noise. The theoretical results indicate that it produces a large measurement error with the increase of the LO intensity noise, but the measurement error has immunity to the product P of the common mode rejection ratio (CMRR) with the LO intensity noise. According to the investigation results and the LO intensity noise, we employ a detector with the CMRR of 67 dB to detect the quantum noise at audio frequencies, the product P of the CMRR with the LO intensity noise is 20 dB below the shot noise limit (SNL), which can induce the measurement error of 0...
October 2, 2017: Optics Express
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