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Stroboscopic Surface Thermal Lensing for Fast Detection of Thermal Defects in Large-Scaled Coating Films.

Tao C, Zhang D, Hong R, Wang Z - ScientificWorldJournal (2015)

Bottom Line: A stroboscopic surface thermal lensing (SSTL) system for the fast detection of thermal-induced defects in large-scaled optical coating films was constructed.The SSTL signal was generated by a set of double-modulators and captured by a high speed matrix camera, respectively.Based on the STL technique, both the mapping of amplitude and the phase of SSTL signal on the whole area of the coatings can be achieved simultaneously.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Modern Optical System, Optical Instruments and Systems Engineering Research Center, Ministry of Education, University of Shanghai for Science and Technology, Shanghai 200093, China.

ABSTRACT
A stroboscopic surface thermal lensing (SSTL) system for the fast detection of thermal-induced defects in large-scaled optical coating films was constructed. The SSTL signal was generated by a set of double-modulators and captured by a high speed matrix camera, respectively. The spot size of both pump laser and probe laser expanded for larger detection area was finished in a single step. Based on the STL technique, both the mapping of amplitude and the phase of SSTL signal on the whole area of the coatings can be achieved simultaneously.

No MeSH data available.


Related in: MedlinePlus

Pulse sequence of double-modulation of four-point correlation for stroboscopic surface thermal lensing.
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Related In: Results  -  Collection


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fig3: Pulse sequence of double-modulation of four-point correlation for stroboscopic surface thermal lensing.

Mentions: The four-point correlation meets our requirement, in virtue of popular modulation mode, more noise-immunity, online operation and high efficiency. Generally, in sinusoidal wave four frames of equidistant signal data are enough to derive the phase shift θs and the amplitude vs as(2)θsarctan⁡S1−S3S2−S4,vs=S1−S32+S2−S42,where S1, S2, S3, and S4 are stroboscopic STL signals on the pixel (x, y) of the film with phase shift π/2, as shown in Figure 3(c). To obtain these four kinds of signal, the phase shift between the pump and probe triggers pulse sequences specified as in Figures 3(a) and 3(b). And thus at least four phase differences, called in-phase and quadrature phase, are obtained:(3)Δϕt=ϕprobe−ϕpumb=2πfti=0,ππ2,3π2.


Stroboscopic Surface Thermal Lensing for Fast Detection of Thermal Defects in Large-Scaled Coating Films.

Tao C, Zhang D, Hong R, Wang Z - ScientificWorldJournal (2015)

Pulse sequence of double-modulation of four-point correlation for stroboscopic surface thermal lensing.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4464688&req=5

fig3: Pulse sequence of double-modulation of four-point correlation for stroboscopic surface thermal lensing.
Mentions: The four-point correlation meets our requirement, in virtue of popular modulation mode, more noise-immunity, online operation and high efficiency. Generally, in sinusoidal wave four frames of equidistant signal data are enough to derive the phase shift θs and the amplitude vs as(2)θsarctan⁡S1−S3S2−S4,vs=S1−S32+S2−S42,where S1, S2, S3, and S4 are stroboscopic STL signals on the pixel (x, y) of the film with phase shift π/2, as shown in Figure 3(c). To obtain these four kinds of signal, the phase shift between the pump and probe triggers pulse sequences specified as in Figures 3(a) and 3(b). And thus at least four phase differences, called in-phase and quadrature phase, are obtained:(3)Δϕt=ϕprobe−ϕpumb=2πfti=0,ππ2,3π2.

Bottom Line: A stroboscopic surface thermal lensing (SSTL) system for the fast detection of thermal-induced defects in large-scaled optical coating films was constructed.The SSTL signal was generated by a set of double-modulators and captured by a high speed matrix camera, respectively.Based on the STL technique, both the mapping of amplitude and the phase of SSTL signal on the whole area of the coatings can be achieved simultaneously.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Modern Optical System, Optical Instruments and Systems Engineering Research Center, Ministry of Education, University of Shanghai for Science and Technology, Shanghai 200093, China.

ABSTRACT
A stroboscopic surface thermal lensing (SSTL) system for the fast detection of thermal-induced defects in large-scaled optical coating films was constructed. The SSTL signal was generated by a set of double-modulators and captured by a high speed matrix camera, respectively. The spot size of both pump laser and probe laser expanded for larger detection area was finished in a single step. Based on the STL technique, both the mapping of amplitude and the phase of SSTL signal on the whole area of the coatings can be achieved simultaneously.

No MeSH data available.


Related in: MedlinePlus