RESUMO
We investigate the testing of collimation by Talbot interferometry with circular gratings. Circular gratings are immune to misalignment owing to rigid body rotations in a plane perpendicular to the optic axis. Experimental results of the investigation are presented, and they are in good agreement with the theoretical predictions. Experimental results verify that collimation testing with circular gratings can be superior to that with linear dual-field gratings.
RESUMO
A laser speckle shearing interferometric technique is used for measuring the temperature profile inside a gaseous flame. The experimental results are compared with the values obtained by a thermocouple and also by speckle photography. Good agreement is seen among the temperatures measured by speckle shearing interferometry, speckle photography, and the thermocouple. Speckle shearing interferometry is easier to implement than speckle photography. This is because in speckle shearing interferometry the accurate positions of the fringes can be known without point-by-point analysis and correction for the halo effect.
RESUMO
A detailed study for measuring the temperature distribution in axisymmetric flames by using a Talbot interferometer with circular gratings is presented. We increased the sensitivity of the interferometer by optimizing the pitch of the grating and the Talbot plane. We compare the experimental results with the values that were measured with a thermocouple to an accuracy of ±0.2% of full scale ±4 digits. Good agreement is seen between the temperatures measured by use of a thermocouple and those measured by use of Talbot interferometry.
RESUMO
In this work a two-hololens imaging system has been used to measure crack-mouth opening displacement and crack-tip opening displacement to determine the stress intensity factor K(1), the crack-tip plastic zone size r(p)(*) and the rotational factor r in a beam specimen having the central edge crack subjected to three-point bending using focused plane speckle photography. Experimental results are in good agreement with theoretical predictions. Current experimental investigations establish that low-cost holographic optics can be advantageously used in speckle metrology to solve complex problems of fracture mechanics.
RESUMO
Use of a two hololens imaging system in speckle metrology is studied in detail. Theoretical analysis and experimental investigations reveal that an almost diffraction-limited performance in speckle metrology can be achieved over the entire object field that can be imaged by this hololens configuration.