Using a low coherence interferometry （LCI） model, a comparison of broadband single-Gaussian and multi-Gaussian light sources has been undertaken. For single-Gaussian sources, the axial resolution improves with the s...Using a low coherence interferometry （LCI） model, a comparison of broadband single-Gaussian and multi-Gaussian light sources has been undertaken. For single-Gaussian sources, the axial resolution improves with the source bandwidth, confirming the coherence length relation that the resolution for single Gaussian sources improves with increasing spectral bandwidth. However, narrow bandwidth light sources result in interferograms with overlapping strata peaks and the loss of individual strata information. For multiple-Gaussian sources with the same bandwidth, spectral side lobes increase, reducing A-scan reliability to show accurate layer information without eliminating the side lobes. The simulations show the conditions needed for the resolution of strata information for broadband light sources using both single and multiple Gaussian models. The potential to use the model to study optical coherence tomography （OCT） light sources including super luminescent diodes （SLDs）, as reviewed in this paper, as well as optical delay lines and sample structures could better characterize these LCI and OCT elements. Forecasting misinformation in the interferogram may allow preliminary corrections. With improvement to the LCI-OCT model, more applications are envisaged.展开更多
The present paper is aimed to study the effect of Gaussian laser light on first and second sound waves in superfluid helium theoretically using optoacoustic method. The mechanism applied in this study is electrostrict...The present paper is aimed to study the effect of Gaussian laser light on first and second sound waves in superfluid helium theoretically using optoacoustic method. The mechanism applied in this study is electrostriction mechanism. This study considers crystal parts of superfluid helium with a zero absorption coefficient applying electrostriction mechanism. Affecting Gaussian laser light on these crystal parts, a spectrum of cylindrical first and second sound waves and cylindrical slow and rapid waves is obtained. Meanwhile, frequency of waves amplitudes proportionate to time period of laser light is calculated.展开更多
文摘Using a low coherence interferometry （LCI） model, a comparison of broadband single-Gaussian and multi-Gaussian light sources has been undertaken. For single-Gaussian sources, the axial resolution improves with the source bandwidth, confirming the coherence length relation that the resolution for single Gaussian sources improves with increasing spectral bandwidth. However, narrow bandwidth light sources result in interferograms with overlapping strata peaks and the loss of individual strata information. For multiple-Gaussian sources with the same bandwidth, spectral side lobes increase, reducing A-scan reliability to show accurate layer information without eliminating the side lobes. The simulations show the conditions needed for the resolution of strata information for broadband light sources using both single and multiple Gaussian models. The potential to use the model to study optical coherence tomography （OCT） light sources including super luminescent diodes （SLDs）, as reviewed in this paper, as well as optical delay lines and sample structures could better characterize these LCI and OCT elements. Forecasting misinformation in the interferogram may allow preliminary corrections. With improvement to the LCI-OCT model, more applications are envisaged.
文摘The present paper is aimed to study the effect of Gaussian laser light on first and second sound waves in superfluid helium theoretically using optoacoustic method. The mechanism applied in this study is electrostriction mechanism. This study considers crystal parts of superfluid helium with a zero absorption coefficient applying electrostriction mechanism. Affecting Gaussian laser light on these crystal parts, a spectrum of cylindrical first and second sound waves and cylindrical slow and rapid waves is obtained. Meanwhile, frequency of waves amplitudes proportionate to time period of laser light is calculated.
