Apochromat

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

Apochromatic lens systems

Abstract: An apochromatic lens system consisting of three identical glass lens elements and a liquid lens element is disclosed. The glass lens elements are made from an inexpensive and readily available optical glass, and the liquid lens element is made from a commercially available immersion oil. The lens elements coact to focus optical radiation passing through the system onto a focal surface with a change in focus of less than one-quarter wavelength over a wavelength range from 0.48 micron to 0.72 micron.

The infrared imaging spectrograph (IRIS) for TMT: imager design

Abstract: We describe an optical design of an imager mode of the IRIS instrument for the Thirty Meter Telescope IRIS is a fully-cryogenic diffraction-limited infrared camera and integral field spectrograph working in the wavelength coverage from 084 to 24 microns The imager mode covers 164" × 164" FOV with a 4096 × 4096 detector array with sampling 4 milli-arcsec/pix There are two challenges in performance which the science cases require in the imager mode 1) rms wavefront error should be less than 30 nm, and 2) optical distortion should be corrected sufficiently to achieve astrometric accuracy of 10 micro-arcsec Among possible optical configurations consisting of reflective and refractive solutions, a refractive solution with apochromatic triplets best meets the requirements The optical system consists of a collimator and camera both of which have a BaF2-Fused Silica- ZnSe apochromatic triplet and a single BaF2 lens near the focus The rms wavefront error of the system including the telescope, adaptive optics, and imager mode is less than 22 nm with ideal optical parameters A sensitivity analysis shows that reasonable amount of errors in fabrication and alignment will give the rms wavefront error of less than 30 nm in 90 % of all cases We also investigate accuracy of the distortion correction and how movable parts affect the correction accuracy We find that uncorrectable distortion correction errors are well below 10 micro-arcsec with reasonable stability and repeatability of the movable parts

Optical design of the Hobby-Eberly Telescope four-mirror spherical aberration corrector

Abstract: The Hobby-Eberly Telescope uses a 11-meter diameter F/1.45 segmented spherical primary mirror. A spherical mirror of this size generates large amounts of spherical aberration. To be used successfully in a tilted optical Arecibo type telescope, the spherical aberration needs to be corrected. This means that tracking of astronomical targets is achieved through moving a tracker optical package which imposes somewhat severe packaging constraints. Given these packaging constraints, novel methods must be employed to correct the aberrations with the Spherical Aberration COrrector contained in the moving tracker optical package. The paper reviews the pertinent requirements, constraints and the resultant design of the Hobby-Eberly Telescope Four Mirror Spherical Aberration Corrector.

Spherical aberration correction and fabrication tolerances in geodesic lenses.

Abstract: This paper describes a theoretical design of an integrated optical geodesic lens using a noncircular overlay to correct spherical aberrations. The corrected lens design can achieve diffraction-limited performance for an on-axis beam with an aperture equal to 90% of the lens diameter. The paper also contains an analysis of the tolerances, which must be met during the fabrication of such a lens to maintain a diffraction-limited spot and prescribed focal length. This analysis showed that the most sensitive parameter is the thickness of the overlay.

Collimating lens for optical system using semiconductor laser

Abstract: A collimating lens system comprises a chromatic aberration correction element and a converging lens which has both surfaces formed of a convex aspherical surface. The converging lens has no aberrations except chromatic aberration. The chromatic aberration correction element has small refractive power adapted to correct a chromatic aberration of the converging lens, and the element is constructed of positive and negative lenses cemented to each other. The positive lens and the negative lens have almost the same refractive index, and have different dispersion.