Related Experiment Video
Updated: Apr 6, 2026
10:39
Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
Published on: October 11, 2016
10.2K
Advanced method of phase shift measurement from variances of interferogram differences
Applied Optics
|July 21, 2015
Summary
This study introduces a novel Fourier domain method for precise phase shift measurement using interferogram variances. Enhancing accuracy involves true variance calculation and spatial apodization, validated by simulations and experiments.
Area of Science:
- Optical metrology
- Interferometry
- Signal processing
Background:
- Accurate phase shift measurement is crucial in various optical applications.
- Traditional methods may face limitations in precision.
- Fourier domain analysis offers potential for improved measurement techniques.
Purpose of the Study:
- To propose a new approach for phase shift measurement using interferogram differences.
- To enhance measurement accuracy through specific data processing techniques.
- To validate the proposed method with numerical simulations and experimental data.
Main Methods:
- Fourier domain analysis of interferogram differences.
- Calculation of true variance of interferogram differences.
- Application of spatial apodization to interferograms.
Main Results:
- The proposed method demonstrates increased accuracy in phase shift measurement.
- True variance calculation and spatial apodization are key factors for accuracy improvement.
- Simulations and experiments confirm the effectiveness of the approach.
Conclusions:
- The novel Fourier domain approach provides a more accurate method for phase shift measurement.
- The study highlights the importance of true variance and spatial apodization for enhanced precision.
- This technique has potential applications in optical metrology and related fields.
Related Concept Videos
01:10Interference: Path Lengths
2.5K
Consider two sources of sound, that may or may not be in phase, emitting waves at a single frequency, and consider the frequencies to be the same.
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
2.5K
01:15NMR Spectroscopy: Chemical Shift Overview
4.1K
The position of the absorption signal of a sample is reported relative to the position of the signal of tetramethylsilane (TMS), which is added as an internal reference while recording spectra. The difference between the absorption frequencies of the sample and TMS (in Hz) is divided by the spectrometer operating frequency (in MHz) to obtain a dimensionless quantity called the chemical shift. It is reported on the δ (delta) scale and expressed in parts per million.
For instance, the proton...
For instance, the proton...
4.1K
01:15Gain
614
Gain and phase shift are properties of linear circuits that describe the effect a circuit has on a sinusoidal input voltage or current. The circuit's behavior that contains reactive elements will depend on the frequency of the input sinusoid. As a result, it is observed that the gain and phase shift will all be frequency functions.
Gain:
Suppose Vin is the input and Vout is the output signal to a circuit.
Gain:
Suppose Vin is the input and Vout is the output signal to a circuit.
614
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
2.3K
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single...
2.3K
01:24Properties of Fourier Transform II
916
The Fourier Transform (FT) is an essential mathematical tool in signal processing, transforming a time-domain signal into its frequency-domain representation. This transformation elucidates the relationship between time and frequency domains through several properties, each revealing unique aspects of signal behavior.
The Frequency Shifting property of Fourier Transforms highlights that a shift in the frequency domain corresponds to a phase shift in the time domain. Mathematically, if x(t) has...
The Frequency Shifting property of Fourier Transforms highlights that a shift in the frequency domain corresponds to a phase shift in the time domain. Mathematically, if x(t) has...
916
01:21Time and frequency -Domain Interpretation of Phase-lag Control
449
Phase-lag controllers are widely used in control systems to improve stability and reduce steady-state errors. A dimmer switch controlling the brightness of a light bulb serves as a practical example of phase-lag control, gradually adjusting the bulb's brightness. Mathematically, phase-lag control or low-pass filtering is represented when the factor 'a' is less than 1.
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any...
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any...
449