Precise focal-length measurement technique with a reflective Fresnel-zone hologram

Abstract

A new technique for precise focal-length measurement with a hologram is presented. This technique is widely applicable and is particularly useful for measuring large, slow lenses. In diffraction, the Fresnel-zone plate hologram emulates the reflective properties of a convex spherical mirror for use during transmission null tests of an optic by use of a phase-shifting interferometer. The hologram is written lithographically and therefore offers a higher degree of precision at a lower cost than its spherical mirror counterpart. A hologram offers the additional benefit of easy characterization by use of the same interferometer employed in examining the test optic. Better than +/-0.01% precision is achieved during measurement of a 9-m focal-length lens by use of a 150-mm aperture interferometer.

Real-time, Multi-wavelength Holographic Recording in Photorefractive Volume Media: Theory and Applications

“…Moiré interferometry (Keren et al, 1988), diffraction gratings (de Angelis et al, 1997), lithographically recorded Fresnel Zone holograms (DeBoo & Sasian, 2003) and digital holography (Anand & Chhaniwal, 2006), among other methods, were successfully applied for lens characterization. The common feature of those works is the fact that they are restricted to focal length measurement only.…”

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

“…For gaining better measurement precision, some interferometric techniques are used [4,5], such as Talbot effect theory, moiré fringe technology, Fizeau phase-shifting interferometer, and Fresnel-zone hologram. Some of these method obtained a measurement precision better than 0.0088% [6], but it is just a results in terms of theory which difficult to calibrate by experiments. The method based on the use of an optical wedge with a small vertex angle is shown experimentally that a focal length of 25 m can be measured with an error of 0.1% [7].…”

Evaluation of focal length of a lens using the Lau effect

“…In addition to methods based on geometrical optics, there are some methods based on physical optics for determining this quantity. [2][3][4][5][6] Lau effect is also has been used for this purpose. 7 In this work we use this effect again for determining of focal length of a lens but with different approach and configuration.…”