Focus retrocollimated interferometry for focal-length measurements

Abstract

Focus retrocollimated interferometry is developed for the measurement of focal lengths of optical lenses and systems, and achievable accuracy is discussed. It is shown that this method can be used to measure both short and long focal lengths simply and with high accuracy.

Calibrated precision of ultra-long focal length measurement utilizing Talbot effect and Moiré technique

“…The deviation of standard focal lens will bring errors to calibration of parameters and, following, to the precision of measurement. The deviation of standard focal length is definition as Eq.8 (8) The deviation of focal length deduced by errors of parameters and angle of rotated moiré fringes is shown by Fig.6. It…”

“…Some paper [8] mentioned, by technical modification one can use Talbot methods to measure not only long focal lengths to a relative accuracy of between 0.2% and 3%. When the focal length is up to 100 meters or much further, the data is under credible because ultra-focal length has a small N.A.…”

Simple and accurate method for determining lens focal length

“…There are a plurality of papers 5 – 37 describing different techniques for focal length measurement. For example, using Talbot imaging, Moire fringes, deflectometry, interferometry, imaging conjugates, and using gratings and holograms.…”

Focal length measurement of a microlens-array by grating shearing interferometry

“…Given that the technology for MLA fabrication is improving [7][8][9][10], the dimensions of MLAs have been decreasing in size and the numbers of sub-lenses have been increasing in more modern optical systems, which make measurements of the MLA harder because the testing needs not only precision but also efficiency. For MLA measuring, classical methods based on geometrical optics cannot fulfill the requirements for high precision and efficient testing [11][12][13][14][15]. To achieve high efficiency, a technology that determines the magnification has been reported [16].…”