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Basic Optical Systems and Simple Photographic Lenses
Published in Daniel Malacara-Hernández, Zacarías Malacara-Hernández, Handbook of OPTICAL DESIGN, 2017
Daniel Malacara-Hernández, Zacarías Malacara-Hernández
It is frequently necessary to produce a well-collimated beam of laser light. A normal telescope objective with a large f-number may be used, but an important requirement is that the focal length be short. An f-number as low as possible is convenient. This imposes the need for an extremely good spherical aberration correction, with a low zonal aberration. As described by Korones and Hopkins (1959), the zonal aberration may be reduced by any of four methods: Choosing the proper glassesUsing an air spaceIntroducing an aspherical surfaceSplitting the positive lens into two
Paraxial Propagation of Gaussian Beams
Published in Glen D. Gillen, Katharina Gillen, Shekhar Guha, Light Propagation in Linear Optical Media, 2017
Glen D. Gillen, Katharina Gillen, Shekhar Guha
Figure 6.6 is an illustration of the effects of the Rayleigh range of the incident beam on the location of the new focal plane. A “well-collimated” beam would be one where the Rayleigh range of the incident beam is very long with respect to the focal plane; i.e., the width of the beam does not change appreciably over a significant distance before the lens. As we can see in the figure, when the Rayleigh range of the incident beam becomes large with respect to the focal length of the lens, the location of the focal plane is a focal length, f, away from the lens.
Spectrometers and Spectroscopes
Published in Abdul Al-Azzawi, Photonics, 2017
Light from the source is sent through a narrow, adjustable slit. The collimator is adjusted to produce a parallel and collimated beam. The light then passes through the prism and is dispersed into a spectrum. The refracted light is focused through the telescope objective and eyepiece lenses and observed by the eye. The angle, through which the telescope arm rotates to view a spectral line, relates to the wavelength of the spectral line. The colours of the light source spectrum are easily identified and diagnosed with the spectrum chart.
Investigation of thermal adiabatic boundary condition on semitransparent wall in combined radiation and natural convection
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2022
The collimated beam radiation (rays travel in a single direction) plays an important role in many engineering applications, e.g., in solar cavity receivers the energy is primarily from collimated beam radiation after reflection from the heliostat field, laser manufacturing, skin cancer, study of greenhouse gas effects, dynamics of a lake, shallow water, dynamics of clouds affected by solar radiation, HVAC systems, etc. In such cases, energy mostly travels in a single direction and plays an important role in the accurate analysis of the system behavior.