Monochromatic in the context of Monochromatic radiation

In optics, a simple lens or singlet lens is a lens consisting of a single simple element. Typical examples include a magnifying glass or a lens in a pair of simple reading glasses.

Simple lenses are prone to aberrations, especially chromatic aberration. They cannot be used for precise imaging and make poor camera lenses. They are commonly used for laser applications, however, where the beams are both monochromatic (minimizing chromatic aberration) and narrow (minimizing spherical aberration).

Hatching (French: hachure) is an artistic technique used to create tonal or shading effects by drawing, painting, or scribing closely spaced parallel lines. When lines are placed at an angle to one another, it is called cross-hatching. Hatching is also sometimes used to encode colours in monochromatic representations of colour images, particularly in heraldry.

Hatching is especially important in essentially linear media, such as drawing and many forms of printmaking, such as engraving, etching, and woodcut. In Western art, hatching originated in the Middle Ages and developed further into cross-hatching, especially in the old master prints of the fifteenth century. Master ES and Martin Schongauer in engraving and Erhard Reuwich and Michael Wolgemut in woodcut were pioneers of both techniques. Albrecht Dürer in particular perfected the technique of crosshatching in both media.

Louise Nevelson (September 23, 1899 – April 17, 1988) was an American sculptor known for her monumental, monochromatic, wooden wall pieces and outdoor sculptures. Born in the Poltava Governorate of the Russian Empire, she emigrated with her family to the United States in 1905. Nevelson learned English at school, as she spoke Yiddish at home.

By the early 1930s she was attending art classes at the Art Students League of New York, and in 1941 she had her first solo exhibition. Nevelson experimented with early conceptual art using found objects, and experimented with painting and printing before dedicating her lifework to sculpture. Usually created out of wood, her sculptures appear puzzle-like, with multiple intricately cut pieces placed into wall sculptures or independently standing pieces, often 3-D. The sculptures are typically painted in monochromatic black or white.

X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique that measures the very topmost 50–60 atoms, 5–10 nm of any surface. It belongs to the family of photoemission spectroscopies in which electron population spectra are obtained by irradiating a material with a beam of X-rays. XPS is based on the photoelectric effect that can identify the elements that exist within a material (elemental composition) or are covering its surface, as well as their chemical state, and the overall electronic structure and density of the electronic states in the material. XPS is a powerful measurement technique because it not only shows what elements are present, but also what other elements they are bonded to. The technique can be used in line profiling of the elemental composition across the surface, or in depth profiling when paired with ion-beam etching. It is often applied to study chemical processes in the materials in their as-received state or after cleavage, scraping, exposure to heat, reactive gasses or solutions, ultraviolet light, or during ion implantation.

Chemical states are inferred from the measurement of the kinetic energy and the number of the ejected electrons. XPS requires high vacuum (residual gas pressure p ~ 10 Pa) or ultra-high vacuum (p < 10 Pa) conditions, although a current area of development is ambient-pressure XPS, in which samples are analyzed at pressures of a few tens of millibar.

In computing, a Unicode symbol is a Unicode character which is not part of a script used to write a natural language, but is nonetheless available for use as part of a text.

Many of the symbols are drawn from existing character sets or ISO/IEC or other national and international standards. The Unicode Standard states that "The universe of symbols is rich and open-ended," but that in order to be considered, a symbol must have a "demonstrated need or strong desire to exchange in plain text." This makes the issue of what symbols to encode and how symbols should be encoded more complicated than the issues surrounding writing systems. Unicode focuses on symbols that make sense in a one-dimensional plain-text context. For example, the typical two-dimensional arrangement of electronic diagram symbols justifies their exclusion. (Legacy characters such as box-drawing characters, Symbols for Legacy Computing and the Symbols for Legacy Computing Supplement, are an exception, since these symbols largely exist for backward compatibility with past encoding systems; a number of electronic diagram symbols are indeed encoded in Unicode's Miscellaneous Technical block.) For adequate treatment in plain text, symbols must also be displayable in a monochromatic setting. Even with these limitations – monochromatic, one-dimensional and standards-based – the domain of potential Unicode symbols is extensive. (However, emojis – ideograms, graphic symbols – that were admitted into Unicode, allow colors although the colors are not standardized. Color-dependent emojis are traditionally rendered using hatching in monochromatic settings.)

Floaters or eye floaters are sometimes-visible deposits (e.g., the shadows of tiny structures of protein or other cell debris projected onto the retina) within the eye's vitreous humour ("the vitreous"), which is normally transparent, or between the vitreous and retina.They can become particularly noticeable when looking at a blank surface or an open monochromatic space, such as a blue sky.Each floater can be measured by its size, shape, consistency, refractive index, and motility. They are also called muscae volitantes (Latin for 'flying flies'), or mouches volantes (from the same phrase in French). The vitreous usually starts out transparent, but imperfections may gradually develop as one ages. The common type of floater, present in most people's eyes, is due to these degenerative changes of the vitreous. The perception of floaters, which may be annoying or problematic to some people, is known as myodesopsia, or, less commonly, as myodaeopsia, myiodeopsia, or myiodesopsia. It is not often treated, except in severe cases, where vitrectomy (surgery) and laser vitreolysis may be effective.

Floaters are visible either because of the shadows that imperfections cast on the retina, or because of the refraction of light that passes through them, and can appear alone or together with several others as a clump in one's visual field. They may appear as spots, threads, or fragments of "cobwebs", which float slowly before the observer's eyes, and move especially in the direction the eyes move. As these objects exist within the eye itself, they are not optical illusions but are entoptic phenomena (caused by the eye itself). They are not to be confused with visual snow, which is similar to the static on a television screen, although these two conditions may coexist as part of a number of visual disturbances which include starbursts, trails, and afterimages.

Raman spectroscopy (/ˈrɑːmən/) (named after physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified.

Raman spectroscopy relies upon inelastic scattering of photons, known as Raman scattering. A source of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range is used, although X-rays can also be used. The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the vibrational modes in the system. Time-resolved spectroscopy and infrared spectroscopy typically yield similar yet complementary information.