Which of the following is a common metrological application of interferometry?

Explanation:

Interferometry:

• Interferometry is a precise measurement technique that uses the phenomenon of interference of light waves to measure small distances, surface irregularities, and refractive index changes. Interferometry is widely used in metrology, which is the science of measurement, to ensure the accuracy and precision of measurements in various applications.

Working Principle: In interferometry, a beam of light is split into two or more paths. These beams travel different paths and are then recombined to create an interference pattern. The resulting interference pattern is a function of the differences in the path lengths that the light has traveled. By analyzing the interference pattern, precise measurements of distance, surface profiles, and other parameters can be obtained.

Advantages:

• High precision and accuracy in measurements.
• Non-contact measurement, making it suitable for delicate surfaces.
• Can measure very small distances and changes in distances.
• Capability to measure a wide range of physical properties.

Disadvantages:

• Requires a stable environment to avoid disturbances in the interference pattern.
• Complex setup and analysis, requiring specialized equipment and expertise.
• High sensitivity to vibrations and temperature changes, which can affect accuracy.

Applications: Interferometry is commonly used in various metrological applications, such as:

• Inspecting machine parts for straightness: Interferometry is extensively used to inspect the straightness of machine parts. By analyzing the interference patterns, deviations from the straightness can be detected with high precision.
• Surface topography measurements: Used to measure the surface roughness and flatness of materials.
• Thickness measurements: Used to measure the thickness of thin films and coatings.
• Refractive index measurements: Used to measure changes in the refractive index of materials.
• Displacement measurements: Used to measure small displacements and vibrations in mechanical systems.