photoelastic การใช้

• The original detection mechanism used in picosecond ultrasonics is based on the photoelastic effect.
• For materials that do not show photoelastic behavior, it is still possible to study the stress distribution.
• Can anyone give some idea as to how to count the number of fringes in a photoelastic material on being loaded.
• Later developers of the photoelastic modulator include J . C Kemp, S . N Jasperson and S . E Schnatterly.
• Photoelastic modulators are resonant devices where the precise oscillation frequency is determined by the properties of the optical element / transducer assembly.
• The first step is to build a model, using photoelastic materials, which has geometry similar to the real structure under investigation.
• The theory of optical detection in multilayer samples, including both interface motion and the photoelastic effect, is now well-developed.
• The principle of operation of photoelastic modulators is based on the photoelastic effect, in which a mechanically stressed sample exhibits birefringence proportional to the resulting strain.
• The principle of operation of photoelastic modulators is based on the photoelastic effect, in which a mechanically stressed sample exhibits birefringence proportional to the resulting strain.
• The basic design of a photoelastic modulator consists of a piezoelectric transducer and a half wave resonant bar; the bar being a transparent material ( now most commonly fused silica ).
• Most noted for his contributions to the field of optics, he studied the double refraction by compression and discovered the photoelastic effect, which gave birth to the field of optical mineralogy.
• After acoustic reflection from the film-substrate interface, the strain pulse returns to the film surface, where it can be detected by a delayed optical photoelastic detection of coherent picosecond acoustic phonon pulses was proposed by Christian Thomsen and coworkers in a collaboration between Brown University and Bell Laboratories in 1984.
• If the signal is either slowly varying or otherwise constant ( essentially a DC signal ), then acousto-optical modulator, photoelastic modulator at a large enough frequency so that 1 / " f " noise drops off significantly, and the lock-in amplifier is referenced to the operating frequency of the modulator.
• Where " n " is the refraction index, " p " is the photoelastic coefficient of the glass, " k " is the Boltzmann constant, and " ? " is the isothermal compressibility . " T " f is a " fictive temperature ", representing the temperature at which the density fluctuations are " frozen " in the material.