Apochromat

About: Apochromat is a research topic. Over the lifetime, 642 publications have been published within this topic receiving 7934 citations.

Aberration analysis based on pinhole-z-scan method near the focal point of refractive systems

Abstract: In this work we present a method used to study the spherical and chromatic aberrations contribution near the focal point of a refractive optical system. The actual focal position is measured by scanning a pinhole attached on the front of a power detector, which are scanned along the optical axis using a motorized stage with 1 μm resolution. Spherical aberration contribution was analyzed by changing the pupil aperture, by modifying the size of the input iris diaphragm and for each case, measuring the actual laser power vs the detector position. Chromatic aberration was analyzed by performing the same procedure but in this case we used an ultra-broad-band femtosecond laser. The results between ML and CW operation were compare. Experimental results are presented.

Variable aberration lens system

Abstract: A variable aberration lens system usable not only as a general photographic lens but also a soft focus lens is provided. The variable aberration lens system includes at least a variable meniscus-shaped air space and cementing surface which are respectively concave against a stop provided therein. A very high resolving power and high contrast can be obtained when the variable aberration lens system is used as the general photographic lens, and a photograph in which an out focus image of the background or foreground is fine can be obtained by varying the width of the air space when the variable aberration lens system is used as the soft focus lens.

Three-lens apochromatic infrared objective - has germanium, arsenic tri:sulphide, and chalogenide glass lens

Abstract: The infra-red objective is for the 8-12 micrometre wavelength range. It comprises three lenses (R1,2, R3,4, R5,6) of which one (R1,2) is germanium, one (R5,6) is arsenic trisulphide, and one (R3,4) is chalcogenide glass such as is known under trade names 19 1173 (Texas instruments) or Amtir 1 (Amorphous Materials Inc.). Dimensional details are specified for two examples of objectives with focal length 250. The lens has less chromatic aberration than prior art lenses.

Adjustable chromatic correction lens

Abstract: An imaging lens device at f/4 has zoomlike variable chromatic and spherochromatic correction for imagery in each of the astronomical U, B, V, and R bands. This lens system can thus take advantage of the full usable wavelength range of CCD cameras extending from 0.35-0.9 micrometers. A first triplet lens group effects the chromatic correction by altering separation between lens elements of the triplet while a second triplet lens group maintains a sharp image focus.

Kinoforms long focal objectives for astronomy

Abstract: A new class of long focal apochromatic optical systems is described which permits the formation of images in different spectral ranges. The systems are composed of kinoform elements combined with conventional optical elements. The correction of monochromatic and chromatic aberrations is discussed theoretically with respect to their occurrence in long-focal, large-f-number astronomical lenses. Kinoform elements are compared to traditional optical elements, and the synthesis of long focal apochromats is shown to be possible with kinoform elements and typical optics. A discussion of diffraction efficiency and spectral selectivity in kinoform elements shows that acceptable characteristics for these optics can be achieved over a wide spectral range. Kinoform element objectives can be applied to high-resolution refractors, stellar sensors, large-telescope guiders, and collimators. The apochromatic lenses based on kinoform elements weigh 30-40 percent less than traditional lenses and offer high correction of chromatic aberrations, low thermal sensitivity, and a minor augmentation of stray light.