Multi-wavelength laser interferometer

Abstract

A multi-wavelength laser interferometer comprises a laser, an aperture diaphragm, a beam expanding secondary mirror, a pinhole diaphragm, a beam splitter prism, a collimating main mirror, a transmission standard mirror, a piezoelectric ceramic transducer, a to-be-measured plane element, a reflection standard mirror, an imaging lens, a hyperspectral camera and a computer. The collimating main mirror in the interferometer is composed of three lenses, and the imaging lens and the beam expanding secondary mirror are identical in parameter and are both single lenses; and in order to reduce the processing difficulty of the lenses in the interferometer and the difficulty of light path adjustment of a whole system, the beam expanding secondary mirror and the collimating main mirror are each provided with one surface which can be a plane. The multi-wavelength laser interferometer can be used for measuring transmission wavefront or reflected wavefront of the to-be-measured plane optical elementin the wavelength range of 600 nm-1600 nm.

Description

technical field [0001] The invention relates to a planar optical element, in particular to a multi-wavelength laser interferometer for interferometric measurement of a planar optical element. Background technique [0002] Laser interferometry is an optical metrology method based on the principle of light interference. It is currently recognized as one of the most effective and accurate technical means for detecting the surface quality of optical components. The working wavelength of the laser interferometer commonly used at home and abroad is a single wavelength, mostly 632.8nm, 1053nm or 1064nm wavelength. However, for some optical components coated with narrow-band filter films, their reflectivity at 632.8nm, 1053nm or 1064nm wavelength is greater than 99% or transmittance is greater than 99%, which makes the commonly used laser interferometers on the market unable to collect to the desired interference fringes, making it impossible to detect them. [0003] For example, ...

AI Technical Summary

Problems solved by technology

[0007] In order to solve the defect that most laser interferometers on the market have only one output wavelength, the present invention proposes a multi-wavelength laser interferometer

The device can measure the transmitted wavefront or reflected wavefront of planar optical elements in the wavelength range of 600nm~1600nm, and the working wavelength covers 632.8nm, 1053nm and 1064nm, and makes up for the existing single wavelength of 632.8nm, 1053nm and 1064nm Disadvantages of laser interferometers not being able to work at many other wavelengths

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