Laser interferometer Su-Jin Kim, GNU & Xiaoyu Ding

Laser Interferometer What’s laser interferometer? The principle of standard interferometer Types of interferometers Applications Xiaoyu Ding

What’s a Laser Interferometer Laser Interferometer: – the instrument used for high precision measurements (distance, angles…. etc.) – it uses interferometry as the basis for measurement. – it uses the very small, stable and accurately defined wavelength of laser as a unit of measure. Xiaoyu Ding

Physics Review Diffraction Diffraction of Water Waves Diffraction is a sure sign that whatever is passing through the hole is a wave. Xiaoyu Ding

Physics Review Diffraction of Light Light, just like a water wave, does spread out behind a hole is the hole is sufficiently small. Light is a electromagnetic wave. Xiaoyu Ding Diffraction of light Wave

Physics Review A Double-Slit Interference Experiment Xiaoyu Ding Interference of Light Visible light Color pattern

Principle of Michelson Interferometer Albert Michelson (1852~1931) – the first American scientist to receive a Nobel prize, invented the optical interferometer. – The Michelson interferometer has been widely used for over a century to make precise measurements of wavelengths and distances. Albert Michelson Xiaoyu Ding

Principle of Michelson Interferometer Michelson Interferometer 1)Separation 2)Recombination 3)Interference A Michelson Interferometer for use on an optical table Xiaoyu Ding

Principle of Michelson Interferometer Analyzing Michelson Interferometer – The central spot in the fringe pattern alternates between bright and dark when Mirror M2 moves. Photograph of the interference fringes produced by a Michelson interferometer. If we can know the spacing distance of M2 between two sequent central bright spots and the number of central bright spots appeared, then we can calculate how long M2 moved. Xiaoyu Ding λ/4 -> bright to dark

He Ne nm wave length is used.

Applications Measurement of Distance – 1) frequency stabilized He-Ne laser tube – 2) combination of beam-splitter and retroreflector – 3) a moving retroreflector – 4) detection electronics Aerotech’s LZR3000 Series Laser Interferometer System Xiaoyu Ding

Applications Other Applications – Measure angles, flatness, straightness, velocity and vibrations, etc. Xiaoyu Ding Rearrangements of the light paths

Resolution XL-80 Laser Measurement System Xiaoyu Ding

References PHYSICS FOR SCIENTISTS AND ENGINEERS, Randall D. Knight, Xiaoyu Ding

Laser interferometer Su-Jin Kim Gyeongsang National University

Linear Distance Measurement The positioning accuracy is measured by comparing the position value displayed by machine with the actual position.

Rectangularity Measurement Measurement of the rectangularity between the x-axis and z-axis.

Straightness Measurements Straightness and parallelism measurements with moving board up to 20 mm.

Reference 5Q Theory 5Q

Renishaw TP0 TP0