Microlenses focal length measurement using Z-scan and parallel moiré deflectometry

Rasouli, Saifollah; Rajabi, Yasser; Sarabi, Hassan

doi:10.1016/j.optlaseng.2013.05.012

Cited by 10 publications

(2 citation statements)

References 21 publications

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“…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.…”

Section: Introductionmentioning

confidence: 99%

Simple and accurate method for determining lens focal length

Sasián

2023

Opt. Eng.

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A simple and accurate method for determining the focal length of a lens is presented.There is no need to know the distance between lens principal planes and can be performed with easily available and inexpensive hardware. Depending on the test lens (TL) f-number, the error on determining focal length can be in the order of 0.1% of the focal length. We discuss determining focal length with the Newton equation f 2 ¼ zz 0 , with the Bessel equation f ¼ ððL − PPÞ 2 − D 2 Þ∕4ðL − PPÞ, with equation f 2 ¼ y 0 ðy þ y 0 Þ, or with equation f ¼ ðy 2 − PP 2 Þ∕4PP.

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Section: Introductionmentioning

confidence: 99%

Simple and accurate method for determining lens focal length

Sasián

2023

Opt. Eng.

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“…Although, this technique is actually an approximation since the focal length is commonly defined from the front principal plane of the lens, and it is usually inaccessible. Other methods based on moiré deflectometry utilize two diffraction gratings and analyze the moiré fringes produced after the second grating when the beam is converging through the lens [5][6][7][8][9][10]. In Refs.…”

Section: Introductionmentioning

confidence: 99%

Near-field diffraction-based focal length determination technique

Torcal-Milla

Sanchez‐Brea

2017

Optics and Lasers in Engineering

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An accurate and simple technique for determining the focal length of a lens is presented. It consists of measuring the period of the fringes produced by a diffraction grating at the near field when it is illuminated with a beam focused by the unknown lens. In paraxial approximation, the period of the fringes varies linearly with the distance. After some calculations, a simple extrapolation of data is performed to obtain the locations of the principal plane and the focal plane of the lens. Thus, the focal length is obtained as the distance between the two mentioned planes. The accuracy of the method is limited by the collimation degree of the incident beam and by the algorithm used to obtain the period of the fringes. We have checked the technique with two commercial lenses, one convergent and one divergent, with nominal focal lengths (+100 ± 1) mm and (−100 ± 1) mm respectively. We have experimentally obtained the focal lengths resulting into the interval given by the manufacturer but with an uncertainty of 0.1%, one order of magnitude lesser than the uncertainty given by the manufacturer.

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