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Stray Light
Stray light is light in an optical system, which was not intended in the design. The light may be from the intended source, but follow paths other than intended, or it may be from a source other than the intended source. This light will often set a working limit on the dynamic range of the system; it limits the signal-to-noise ratio or contrast ratio, by limiting how dark the system can be. Ocular straylight is stray light in the human eye. Optical systems Monochromatic light Optical measuring instruments that work with monochromatic light, such as spectrophotometers, define stray light as light in the system at wavelengths (colors) other than the one intended. The stray light level is one of the most critical specifications of an instrument. For instance, intense, narrow absorption bands can easily appear to have a peak absorption less than the true absorption of the sample because the ability of the instrument to measure light transmission through the sample is limited by the st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum and polarization. Its speed in a vacuum, 299 792 458 metres a second (m/s), is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Telescope
An optical telescope is a telescope that gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electronic image sensors. There are three primary types of optical telescope: * Refracting telescopes, which use lenses and less commonly also prisms (dioptrics) * Reflecting telescopes, which use mirrors (catoptrics) * Catadioptric telescopes, which combine lenses and mirrors An optical telescope's ability to resolve small details is directly related to the diameter (or aperture) of its objective (the primary lens or mirror that collects and focuses the light), and its light-gathering power is related to the area of the objective. The larger the objective, the more light the telescope collects and the finer detail it resolves. People use optical telescopes (including monoculars and binoculars) for outdoor activities such as observational as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synopsys
Synopsys is an American electronic design automation (EDA) company that focuses on silicon design and verification, silicon intellectual property and software security and quality. Products include tools for logic synthesis and physical design of integrated circuits, simulators for development and debugging environments that assist in the design of the logic for chips and computer systems. In recent years, Synopsys has expanded its products and services to include application security testing. Synopsys has gained attention due to its relationship with various Chinese state entities. In 2018, Synopsys formed a partnership with the People's Liberation Army National Defence University and, in 2022, the company came under investigation by the United States Department of Justice for technology transfers to sanctioned entities in China. History Synopsys was founded by Aart J de Geus and David Gregory in 1986 in Research Triangle Park, North Carolina. The company was initially est ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FRED Software
Fred Optical Engineering Software (FRED) is a commercial 3D CAD computer program for optical engineering used to simulate the propagation of light through optical systems. Fred can handle both incoherent and coherent light using Gaussian beam propagation. The program offers a high level of visualization using a WYSIWYG (What You See Is What You Get) parametric interface. According to the publisher, Photon Engineering, the name "Fred" is not an acronym, and does not mean anything. Fred allows for non-sequential raytracing with support to raytrace on up to 63 cores. Fred also features a downhill simplex optimizer where the user can specify variables, merit function and multiple targets for optimization. The program can import and export IGES, STEP, and OBJ CAD formats. Fred is also compatible with other hardware measured light source measurement software such as ProSource. Fred can also interact with MATLAB and Mathematica using an OLE Automation Client/Server interface. Fred w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASAP (software)
The Advanced Systems Analysis Program (ASAP) is optical engineering software used to simulate optical systems. ASAP can handle coherent as well as incoherent light sources. It is a non-sequential ray tracing tool which means that it can be used not only to analyze lens systems but also for stray light analysis. It uses a Gaussian beam approximation for analysis of coherent sources. See also *Optical engineering *Optical lens design *List of ray tracing software Ray tracing is a technique that can generate near photo-realistic computer images. A wide range of free software and commercial software Commercial software, or seldom payware, is a computer software that is produced for sale or that serves co ... External links NASA Tech article on ASAPBreault Research Organization Website Optical software Windows-only software {{graphics-software-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Design
Optical lens design is the process of designing a lens to meet a set of performance requirements and constraints, including cost and manufacturing limitations. Parameters include surface profile types (spherical, aspheric, holographic, diffractive, etc.), as well as radius of curvature, distance to the next surface, material type and optionally tilt and decenter. The process is computationally intensive, using ray tracing or other techniques to model how the lens affects light that passes through it. Design requirements Performance requirements can include: #Optical performance (image quality): This is quantified by various metrics, including encircled energy, modulation transfer function, Strehl ratio, ghost reflection control, and pupil performance (size, location and aberration control); the choice of the image quality metric is application specific. #Physical requirements such as weight, static volume, dynamic volume, center of gravity and overall configuration requirements. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Leak
A light leak is a hole or gap in the body of a camera, or other optical instrument, where light is able to "leak" into the normally light-tight chamber, exposing the film or sensor with extra light. This light is diffuse, although parts within the camera may cast shadows or reflect it in a particular way. For most purposes this is considered a problem. Within the lomography movement it is seen as a positive effect, giving photos character. One frequent source of light leaks in 35 mm cameras is around the film door due to degrading foam. Replacing the foam is a simple matter. Medium format system cameras or large format cameras may have leaks between their various interchangeable parts or in old leather bellows. Electrical tape is often used to repair light leaks in these cases. A light leak, considered as a problem, is a kind of stray light. It is possible to have a "virtual" light leak in spectral regions, like portions of the IR spectrum at room temperature, where surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirror
A mirror or looking glass is an object that Reflection (physics), reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the image in an equal yet opposite angle from which the light shines upon it. This allows the viewer to see themselves or objects behind them, or even objects that are at an angle from them but out of their field of view, such as around a corner. Natural mirrors have existed since prehistoric times, such as the surface of water, but people have been manufacturing mirrors out of a variety of materials for thousands of years, like stone, metals, and glass. In modern mirrors, metals like silver or aluminium are often used due to their high reflectivity, applied as a thin coating on glass because of its naturally smooth and very Hardness (materials science), hard surface. A mirror is a Wave (physics), wave reflector. Light consis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuse Reflection
Diffuse reflection is the reflection (physics), reflection of light or other radiation, waves or particles from a surface such that a ray (optics), ray incident on the surface is scattering, scattered at many angles rather than at just one angle as in the case of specular reflection. An ''ideal'' diffuse reflecting surface is said to exhibit Lambertian reflection, meaning that there is equal luminance when viewed from all directions lying in the half-space (geometry), half-space adjacent to the surface. A surface built from a non-absorbing powder such as plaster, or from fibers such as paper, or from a polycrystalline material such as white marble, reflects light diffusely with great efficiency. Many common materials exhibit a mixture of specular and diffuse reflection. The visibility of objects, excluding light-emitting ones, is primarily caused by diffuse reflection of light: it is diffusely-scattered light that forms the image of the object in the observer's eye. Mechanism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-reflective Coating
An antireflective, antiglare or anti-reflection (AR) coating is a type of optical coating applied to the surface of lenses, other optical elements, and photovoltaic cells to reduce reflection. In typical imaging systems, this improves the efficiency since less light is lost due to reflection. In complex systems such as cameras, binoculars, telescopes, and microscopes the reduction in reflections also improves the contrast of the image by elimination of stray light. This is especially important in planetary astronomy. In other applications, the primary benefit is the elimination of the reflection itself, such as a coating on eyeglass lenses that makes the eyes of the wearer more visible to others, or a coating to reduce the glint from a covert viewer's binoculars or telescopic sight. Many coatings consist of transparent thin film structures with alternating layers of contrasting refractive index. Layer thicknesses are chosen to produce destructive interference in the beams r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (optics)
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), usually arranged along a common axis. Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called lenses, such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses. Lenses are used in various imaging devices like telescopes, binoculars and cameras. They are also used as visual aids in glasses to correct defects of vision such as myopia and hypermetropia. History The word ''lens'' comes from '' lēns'', the Latin name of the lentil (a seed of a lentil plant), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock In Amplifier
A lock-in amplifier is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment. Depending on the dynamic reserve of the instrument, signals up to a million times smaller than noise components, potentially fairly close by in frequency, can still be reliably detected. It is essentially a homodyne detector followed by low-pass filter that is often adjustable in cut-off frequency and filter order. The device is often used to measure phase shift, even when the signals are large, have a high signal-to-noise ratio and do not need further improvement. Recovering signals at low signal-to-noise ratios requires a strong, clean reference signal with the same frequency as the received signal. This is not the case in many experiments, so the instrument can recover signals buried in the noise only in a limited set of circumstances. The lock-in amplifier is commonly believed to have been invented by Princeton University physicist Robert H. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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