Optics is the science that studies the laws and properties of light, its refraction and absorption, and the media of the eye in that relationship. It can also be noted as the professional practice of preparing ophthalmic lens prescriptions, dispensing eyeglasses, making and fitting contact lenses. It also refers to the apparatus composed of lenses and mirrors, which is used to see enlarged prints and drawings. It can also be defined as point of view when considering an issue or something else. Knowing the laws of optics allows us to understand how images are formed.
What is Optics
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It is the science belonging to physics that studies the laws, behavior, composition and expressions of light. This word comes from Latin, which means "relative to vision." In general, visible light, infrared and ultraviolet radiation are studied, since it is a type of electromagnetic radiation.
Because it studies light, its capture, interpretation and its different phenomena, many others use this science. Thanks to it, devices such as lenses could be developed, which were used for the invention of devices for scientific purposes such as microscopes, telescopes, fiber optic systems, mirrors, thus favoring the fields of medicine, engineering, astronomy, biology and photography..
Also when talking about what optics is, the term refers to the professional practice of applying correction to human vision, which includes ophthalmology and optometry, so that, after different studies of human vision, can offer the improvement of it through optical transmitting devices called lenses, and thus the deficiencies in the way of perceiving light in the eyes, is complemented and improved with the necessary adjustments.
The involves optical photography, since the camera is a device that records and processes the light through a complex system of elements working as the human eye, body to sense light and color, to finally interpret the brain. The cameras would thus produce what in the human brain would be reflected every time something is seen through the eyes.
The term is usually also referred to a point of view or opinion on some aspect or situation. It is called "optics", because this point of view will be according to the "vision" or with the "eye that is looking at it."
Optics and human vision
Optics, whose object of study is light, is related to human vision. The eye is the perfect photoreceptor organ, since its complexity allows light to pass through them, adjusting its capture and giving shape, color, shades, depth and textures to the objects, places or people that are in front of it. the.
This complex system is not only made up of the eye, it also involves the brain, which is in charge of processing the images captured by said visual organ.
The eye is mainly composed of:
- The cornea:
It is the part that is in contact with the outside and its transparent composition covers the lens and the iris.
- Iris:
It is a dilator muscle that increases and decreases the size of the pupil. In it the color of the eyes is defined.
- Pupil:
It is the hole in the center of the iris that regulates the passage of light.
- Crystalline:
It is located behind the iris and is the "lens" and performs the focus of vision. Its curvature and thickness will vary as you focus according to the distance from what you are observing.
- Aqueous humor:
It is a liquid that is between the lens and the cornea, feeding both parts, allowing the eye pressure to be constant.
- Sclera:
It is what covers and protects the eyeball, which gives it its white color. The anterior part is attached to the cornea, and the posterior part to the optic nerve.
- Conjunctiva:
It is a membrane that covers the sclera, allowing disinfection and lubrication of the eye.
- Choroid:
It is the part where the blood vessels and connective tissue are found, which keeps the eye oxygenated, nourished and with a constant temperature.
- Vitreous humor:
It is a jelly-like liquid that is present in the entire eyeball, giving it firmness, to cushion impacts, fix the retina and maintain intraocular pressure.
- Retina:
It is the most important structure, since it is the receiving organ of vision itself. In it is the presence of rods or rods (light-sensitive photo receptor cell and does not perceive colors) and cones (photo receptor cells responsible for perceiving color).
- Optic nerve:
It is one of the twelve cranial nerves, and it is a set of fibers that transmits to the cerebral optic chiasm (where the fibers of both eyes intersect), where the visual information captured is sent to the brain in the form of electrical signals.
The optics of photography
In the field of photography, it is one of the areas that has benefited from what optics studies, as it is the basic concept par excellence.
The photographic camera is a device that allows images to be captured through its components present in the camera body. This invention was created by emulating organic vision (the eye), achieving a unique and unrepeatable moment permanently.
Compared to the eye, the camera has similar elements and its functionality is the same. In order to capture a good photograph, you must know some basic concepts to take into account:
- Shutter speed
It is the speed with which the camera lets light enter its sensor. It does so through the shutter (trigger), which will regulate the time that it will remain open. This process is known as exposure.
- Depth of field
It is the contrast between those areas to be photographed that are sharp compared to those that are not well focused. Here the focal point is handled, which is the one that will have the point of sharpness, being able to have a distance in front of and behind it, appearing out of focus.
- ISO sensitivity
Is an important element in the triangle of exposure (of which also form part shutter speed and the opening of the diaphragm). This defines the amount of light that a camera requires to take a picture.
- White balance
This process is where color levels in photos are counteracted. It is achieved through the correct adjustment of the three basic colors in the light (red, green and blue).
Knowing these aspects, it will be possible to choose a camera more correctly according to the purpose for which it is acquired. The most important parts of it are:
What is classical optics
It is the one that is made up of physical optics and geometric optics, where both describe light as different phenomena, since one establishes that it is undulatory, while the other is an impulse that travels in a straight line. To understand what classical optics is, it is necessary to know both models:
Geometric optics
Geometric optics explains that light has a constant speed and propagates as rays that travel in a straight line, which will be deflected when they are achieved with a surface or will be reflected, so it is governed by the laws of reflection and refraction of the light, without taking into account other phenomena.
This model allows obtaining the formulas of mirrors and lenses through geometry, and the study of phenomena such as rainbows, prisms and the propagation of light.
Physical optics
In physical optics, the propagation of light is wave, which has the characteristics of an electromagnetic wave. Hence, it takes into account phenomena such as interference, diffraction, reflectivity and transmittance.
This type of optics is used to predict what the behavior of an optical system will be like without knowing in what medium the waves are being agitated. They are considered electromagnetic waves because they also travel at their speed, which is why they are considered that way at present, with the exception of the quantum model (light is a particle and it is a wave), which would complement the knowledge about what it is. classical optics.
Elements of optics
There are several elements in this field that must be known to define what is optical. Namely, the following:
- Electromagnetic waves
They are those waves that do not require any physical means for their propagation.
- Frequency
It is the number of times per second that the wave repeats. The frequency of these waves will determine a color, since each one vibrates to a different one.
- Rays and beams of light
The rays of light come from the geometric model in which they would be the imaginary line of their path. The light beams are the set of rays or particles (quantum method) of the same origin propagated without scattering.
- Wavelength and color
It is the distance that the light has traveled when making a complete vibration. According to the wavelength, the colors are measured.
- The spectre
It is an important concept within the elements of optics, as it is the set of all the vibrational frequencies of electromagnetic waves, in this case, of light.
- Reflection
There are two types: mirror image and diffuse reflection. The first describes the brightness in mirrors, whose reflection is simple and predictable, which allows reflected images that are close to reality. The second refers to the one generated on non-shiny surfaces, whose reflection can only be described statistically.
- Dispersion
It is when different frequencies of light have different speeds, since light is the combination of all colors (frequencies). An example in nature is the rainbow.
What are optical illusions
It is the erroneous perception about the characteristics of an object, set, person or any image that is being seen, that is, that they are far from objective reality. To know what optical illusions are, it is necessary to take into account that in this process, psychological and physiological factors play an important role.
The psychological, because in these cases the brain misinterprets the visual information that is captured, and physiological, because it will depend on whether the object is being viewed intensely, which affects the receptors of the retina.
What is fiber optics
It is a transparent super fine wire, made of plastic or glass, through which pulses of light are sent. It is a transmission medium generally used in data networks. Its thickness is similar to that of a human hair. These light impulses transmit large amounts of information, television signal, Internet, telephone communication, and so on.
Fiber optic characteristics
- Electricity is not necessary for its use.
- It is made up of a core, mantle, tensioners, cladding, and jacket.
- Its core is plastic or germanium and silicon oxide.
- In its nucleus there is a greater refraction than in its cover.
- It is used in the telecommunications area.
- Its transmission speed exceeds that of ordinary cables.
- They are immune to electromagnetic interference.
- They are used with LAN to transmit long range.
- Its thickness is 0.1 millimeters thick and transparent.
- It consists of a light source (LED or laser); a transmitting medium (fiber optic); and the light detector (photodiode).
Fiber optic applications
Optical fibers can be used as conventional wires, both in data processing systems environments in autonomous environments. For example, in airplanes, in geographic networks or the systems of long urban lines supported by telephone companies.
