High‐precision phase‐velocity measurements utilizing a continuous‐wave feedback technique

1978 ◽  
Vol 63 (6) ◽  
pp. 1919-1922 ◽  
Author(s):  
K. L. Telschow ◽  
J. W. Stasiak
Keyword(s):  
Phase Velocity ◽  
High Precision ◽  
Continuous Wave ◽  
Velocity Measurements ◽  
Precision Phase

scholarly journals High-precision optical fiber pressure sensor using frequency-modulated continuous-wave laser interference

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025038
Author(s):  
Lang Bai ◽  
Gang Zheng ◽  
Bin Sun ◽  
Xiongxing Zhang ◽  
Qiming Sheng ◽  
...  
Keyword(s):  
Optical Fiber ◽  
High Precision ◽  
Pressure Sensor ◽  
Continuous Wave ◽  
Continuous Wave Laser ◽  
Laser Interference ◽  
Wave Laser

A 2-µm Continuous-Wave Laser System for Safe and High-Precision Dissection During NOTES Procedures

2010 ◽  
Vol 55 (9) ◽  
pp. 2463-2470 ◽  
Author(s):  
Xavier Dray ◽  
Gianfranco Donatelli ◽  
Devi Mukkai Krishnamurty ◽  
Elena Dubcenco ◽  
Ronald J. Wroblewski ◽  
...  
Keyword(s):  
High Precision ◽  
Continuous Wave ◽  
Laser System ◽  
Continuous Wave Laser ◽  
Wave Laser

scholarly journals Densified Pupil Spectrograph as High-precision Radial Velocimetry: From Direct Measurement of the Universe’s Expansion History to Characterization of Nearby Habitable Planet Candidates

2022 ◽  
Vol 163 (2) ◽  
pp. 63
Author(s):  
Taro Matsuo ◽  
Thomas P. Greene ◽  
Mahdi Qezlou ◽  
Simeon Bird ◽  
Kiyotomo Ichiki ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Direct Measurement ◽  
High Precision ◽  
Resolving Power ◽  
Line Of Sight ◽  
High Dispersion ◽  
Velocity Measurements ◽  
Habitable Planet ◽  
Airy Disk

Abstract The direct measurement of the universe’s expansion history and the search for terrestrial planets in habitable zones around solar-type stars require extremely high-precision radial-velocity measures over a decade. This study proposes an approach for enabling high-precision radial-velocity measurements from space. The concept presents a combination of a high-dispersion densified pupil spectrograph and a novel line-of-sight monitor for telescopes. The precision of the radial-velocity measurements is determined by combining the spectrophotometric accuracy and the quality of the absorption lines in the recorded spectrum. Therefore, a highly dispersive densified pupil spectrograph proposed to perform stable spectroscopy can be utilized for high-precision radial-velocity measures. A concept involving the telescope’s line-of-sight monitor is developed to minimize the change of the telescope’s line of sight over a decade. This monitor allows the precise measurement of long-term telescope drift without any significant impact on the Airy disk when the densified pupil spectra are recorded. We analytically derive the uncertainty of the radial-velocity measurements, which is caused by the residual offset of the lines of sight at two epochs. We find that the error could be reduced down to approximately 1 cm s−1, and the precision will be limited by another factor (e.g., wavelength calibration uncertainty). A combination of the high-precision spectrophotometry and the high spectral resolving power could open a new path toward the characterization of nearby non-transiting habitable planet candidates orbiting late-type stars. We present two simple and compact highly dispersed densified pupil spectrograph designs for cosmology and exoplanet sciences.

High-precision phase-shifting interferometry with spherical wavefront reference

2012 ◽  
Vol 52 (1) ◽  
pp. A188 ◽  
Author(s):  
Xianfeng Xu ◽  
Guangcan Lu ◽  
Yanjie Tian ◽  
Guoxia Han ◽  
Hongguang Yuan ◽  
...  
Keyword(s):  
High Precision ◽  
Phase Shifting ◽  
Phase Shifting Interferometry ◽  
Precision Phase ◽  
Spherical Wavefront

Validity of Doppler Measurements of Anterior Cerebral Artery Blood Flow Velocity: Correlation with Brain Blood Flow in Piglets

PEDIATRICS ◽  
1983 ◽  
Vol 72 (4) ◽  
pp. 526-531
Author(s):  
Nancy B. Hansen ◽  
Barbara S. Stonestreet ◽  
Ted S. Rosenkrantz ◽  
William Oh
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Continuous Wave ◽  
Anterior Cerebral Artery ◽  
Brain Blood Flow ◽  
Velocity Measurements ◽  
Doppler Flow ◽  
Continuous Wave Doppler

Continuous wave Doppler ultrasonography through the anterior fontanel has recently been used to assess changes in cerebral blood flow in human neonates. There has been controversy concerning whether measurements of Doppler blood flow velocity indeed correlate with brain blood flow. An in vivo correlation was performed between brain blood flow as measured by the microsphere method and Doppler flow velocity measurements of the cerebral arteries via an artificial fontanel in young piglets. The peak systolic velocity (r = .76, P < .001), end diastolic velocity (r = .72, P < .001) and area under the velocity curve (r = .86, P<.001) all showed significant positive correlations with brain blood flow. The pulsatility index did not correlate with brain blood flow. Although continuous wave Doppler flow velocity measurements of the anterior cerebral artery cannot quantitatively assess cerebral blood flow, this methodology can be used to correlate changes in cerebral blood flow and provide a meaningful trend analysis following physiologic or pharmacologic perturbation of the cerebral circulation.

Measurement Errors in 632.8 nm High Precision Phase-Shifting Fizeau Interferometer

2010 ◽  
Vol 47 (4) ◽  
pp. 041202
Author(s):  
魏豪明 Wei Haoming ◽  
邢廷文 Xing Tingwen ◽  
李云 Li Yun ◽  
刘志祥 Liu Zhixiang
Keyword(s):  
High Precision ◽  
Measurement Errors ◽  
Phase Shifting ◽  
Fizeau Interferometer ◽  
Precision Phase

A high precision phase reconstruction algorithm for multi-laser guide stars adaptive optics

2016 ◽  
Vol 25 (9) ◽  
pp. 094214 ◽  
Author(s):  
Bin He ◽  
Li-Fa Hu ◽  
Da-Yu Li ◽  
Huan-Yu Xu ◽  
Xing-Yun Zhang ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
High Precision ◽  
Reconstruction Algorithm ◽  
Phase Reconstruction ◽  
Laser Guide Stars ◽  
Precision Phase ◽  
Laser Guide
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