Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Retroreflector shopping experience:

1. Compare - without doubt the biggest advantage that the Retroreflector offers shoppers today is the ability to compare thousands of Retroreflector at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Retroreflector? Wrong! If the Retroreflector is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Retroreflector then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Retroreflector? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Retroreflector and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Retroreflector wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Retroreflector then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Retroreflector site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Retroreflector, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Retroreflector, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

{{Infobox laboratory equipment| name = Retroreflector| image = Corner-Cube.jpg| caption = Gold corner cube retroreflector| acronym =| other_name =| uses = Optical delay line
Distance measurement] a wave front back along a vector that is parallel to but opposite in direction from the angle of incidence. This is unlike a mirror, which does that only if the mirror is exactly perpendicular to the wave front.

Types of retroreflectors Retroreflection is usually obtained in one of two ways:
  • with a set of three mutually perpendicular mirrors which form a corner (a corner reflector or corner cube), or
  • with reflecting and refracting optical elements arranged so that the focal surface of the refractive element coincides with the reflective surface, typically a transparency (optics) sphere and a spherical mirror - this same effect may be achieved with a single transparency (optics) sphere provided that the refractive index of the material is exactly two times the refractive index of the medium from which the radiation is incident. In that case, the sphere surface behaves as a concave spherical mirror with the required curvature for retroreflection. This is conventionally known as a Cat's eye (road) retroreflector in either configuration.


    • The term cat's eye derives from the resemblance of the cat's eye retroreflector to the optical system that produces the well-known phenomenon of "glowing eyes" in cats and many other vertebrates (which are of course only reflecting light, rather than actually glowing). The combination of the eye's lens (anatomy) and the aqueous humor form the refractive converging system, while the tapetum lucidum behind the retina forms the spherical concave mirror. Because the function of the eye is to form an image on the retina, an eye focused on a distant object has a focal surface that approximately follows the reflective tapetum lucidum structure, which is the condition required to form a good retroreflection.

    Corner retroreflectors occur in two varieties. In the more common form, the corner is literally the truncated corner of a cube of transparent material such as conventional optical glass. In this structure, the reflection is achieved either by total internal reflection or silvering of the outer cube surfaces. The second form uses mutually perpendicular flat mirrors bracketing an air space. These two types have similar optical properties.

    A retroflector may consist of many very small versions of these structures incorporated in a thin sheet or in paint. In the case of paint containing glass beads, the paint glues the beads to the surface where retroreflection is required, and the beads protrude, their diameter being about twice the thickness of the paint.

    A third, much less common way of producing a retroreflector is to use the nonlinear optics phenomenon of nonlinear optics#Optical phase conjugation. This technique is used in advanced optics systems such as high-power lasers and optical fibre. Phase conjugate mirrors require a comparatively expensive and complex apparatus, as well as large quantities of power (as nonlinear optical processes can be efficient only at high enough intensities). However, phase conjugate mirrors have an inherently much greater accuracy in the direction of the retroreflection, which in passive elements is limited by the mechanical accuracy of the construction.

    Applications Retroreflectors on roads Retroreflection (sometimes called retroflection) is used on road surfaces, road signs, vehicles and clothing (large parts of the surface of special safety clothing, less on regular coats). When the headlights of a car illuminate a retroreflective surface, the reflected light is directed towards the car and its driver, and not wasted by going in all directions as with diffuse Reflection (physics). However, a pedestrian can see a retroreflective surface in the dark only if there is a light source directly between them and the reflector, e.g. a torch they carry, or directly behind them, e.g. a car approaching from behind. "Cat's eye (road)" are a particular type of retroreflector embedded in the road surface, used mostly in the UK and southern parts of the United States.

    Corner reflectors are better at sending the light back to the source over long distances, while spheres are better at sending the light to a receiver somewhat off-axis from the source, as when the light from headlights is reflected into the driver's eyes.

    Retroreflectors can be embedded in the road (level with the road surface), or can be raised above the road surface. raised pavement marker are visible for a very long distance (typically 0.5-1 kilometer or more), while sunken reflectors are only visible at very close range due to the higher angle required to properly reflect the light. Raised reflectors are not generally used in areas that regularly experience snow during winter, as passing snowplows will tear them off the roadway. The stress on the roadway caused by cars running over any embedded objects also contributes to accelerated wear and pothole formation.

    Retroreflective road paint is thus very popular in Canada and increasingly the northern parts of the United States, as it is not affected by the passage of snowplows and does not affect the interior of the roadway. Where weather permits, embedded retroreflectors are preferred as they last much longer than road paint, which is weathered by the elements and ground away by the passage of vehicles.

    Retroreflectors used in motorcycle safety Conspicuity, or visibility as outlined by The Motorcycle Safety Foundation greatly increases a motorcyclist's chances of being seen by motorists at night. Placing retroreflective patches on clothing and helmets greatly increases the visibility of bikers and pedestrians to oncoming motorists.

    Many materials appear to have some small degree of reflectivity, but retroreflective materials bounce the greatest amount of light back toward a light source. This makes them especially visible in dark conditions. Some patches claim to be reflective, but only retroreflective materials can be seen from more than a few feet away at night. Retroreflectivity of materials is measured in candle power. Official data says that white clothing performs up to 0.3 candle power. A vehicle license plate comes in at a level of 50. A conforming retro-reflective material has 500 candle power. There is a direct relationship between reflective index (candle power), and the distance from which it can be seen.

    Retroreflectors on the Moon The Apollo 11, Apollo 14, and Apollo 15 missions left retro-reflectors on the Moon as part of the Lunar Laser Ranging Experiment. They are commonly considered to be one of the strongest pieces of evidence against a Apollo moon landing hoax accusations. Additionally the unmanned Soviet Lunokhod 1 and Lunokhod 2 rovers carried smaller arrays. Reflected signals were initially received from Lunokhod 1, but no return signals have been detected since 1971, at least in part due to some uncertainty in its location on the Moon. Lunokhod 2's array continues to return signals to Earth. Even under good viewing conditions, only a single reflected photon is received every few seconds. This makes the job of filtering laser-generated photons from naturally-occurring photons challenging.

    Retroreflectors in Earth orbit LAGEOS, or Laser Geodynamics Satellites, are a series of scientific research satellites designed to provide an orbiting laser ranging benchmark for geodynamical studies of the Earth. There are two LAGEOS spacecraft, LAGEOS-1 launched in 1976, and LAGEOS-2 launched in 1992. As of 2004, both LAGEOS spacecraft are still in service.

    Retroreflectors and invisibility Retroreflective clothing, combined with a properly set up camera and projector, can be used to achieve the effect of partial invisibility when viewed from a single direction.

    More from BBC:

    Howstuffworks has a good article on invisibility cloaks which are based on retroreflectors. See

    Retroreflectors and communications Modulated retroreflectors, in which the reflectance is changed over time by some means, are the subject of research and development for free-space optical communications networks. The basic concept with such systems is that a low-power remote system, such as a sensor mote, can receive an optical signal from a base station and reflect the modulated signal back to the base station. Since the base station supplies the optical power, this allows the remote system to communicate without excessive power consumption. Modulated retroreflectors also exist in the form of modulated phase-conjugate mirrors (PCMs). In the latter case, a "time-reversed" wave is generated by the PCM, with temporal encoding of the phase-conjugate wave (see, e.g., reference 6).

    Cheap plastic corner retroreflectors are using as an aiming device in user-controlled technology optical datalink device RONJA. The aiming is done in night and the necessary retroreflector area depends on aiming distance and ambient lighting from street lamps. The optical receiver itself behaves as a weak retroreflector, because contains a large precisely focused lens (optics) and shiny object in the focal plane. This allows aiming without a retroreflector for short range.

    Retroreflectors and surveying In surveying with a total station or robot, the instrument man or robot aims a laser beam at a corner cube retroreflector held by the rodman. The instrument measures the propagation time of the light and converts it to a distance.

    Retroreflectivity used to detect digital cameras The sensor system of common (non-SLR) digital cameras is retroreflective. Researchers have used this property to demonstrate a system to prevent unauthorized photographs by detecting digital cameras and beaming a highly-focused beam of light into the lens.

    Other uses

    References

    External links

    {{Infobox laboratory equipment| name = Retroreflector| image = Corner-Cube.jpg| caption = Gold corner cube retroreflector| acronym =| other_name =| uses = Optical delay line
    Distance measurement] a wave front back along a vector that is parallel to but opposite in direction from the angle of incidence. This is unlike a mirror, which does that only if the mirror is exactly perpendicular to the wave front.

    Types of retroreflectors Retroreflection is usually obtained in one of two ways:
  • with a set of three mutually perpendicular mirrors which form a corner (a corner reflector or corner cube), or
  • with reflecting and refracting optical elements arranged so that the focal surface of the refractive element coincides with the reflective surface, typically a transparency (optics) sphere and a spherical mirror - this same effect may be achieved with a single transparency (optics) sphere provided that the refractive index of the material is exactly two times the refractive index of the medium from which the radiation is incident. In that case, the sphere surface behaves as a concave spherical mirror with the required curvature for retroreflection. This is conventionally known as a Cat's eye (road) retroreflector in either configuration.


    • The term cat's eye derives from the resemblance of the cat's eye retroreflector to the optical system that produces the well-known phenomenon of "glowing eyes" in cats and many other vertebrates (which are of course only reflecting light, rather than actually glowing). The combination of the eye's lens (anatomy) and the aqueous humor form the refractive converging system, while the tapetum lucidum behind the retina forms the spherical concave mirror. Because the function of the eye is to form an image on the retina, an eye focused on a distant object has a focal surface that approximately follows the reflective tapetum lucidum structure, which is the condition required to form a good retroreflection.

    Corner retroreflectors occur in two varieties. In the more common form, the corner is literally the truncated corner of a cube of transparent material such as conventional optical glass. In this structure, the reflection is achieved either by total internal reflection or silvering of the outer cube surfaces. The second form uses mutually perpendicular flat mirrors bracketing an air space. These two types have similar optical properties.

    A retroflector may consist of many very small versions of these structures incorporated in a thin sheet or in paint. In the case of paint containing glass beads, the paint glues the beads to the surface where retroreflection is required, and the beads protrude, their diameter being about twice the thickness of the paint.

    A third, much less common way of producing a retroreflector is to use the nonlinear optics phenomenon of nonlinear optics#Optical phase conjugation. This technique is used in advanced optics systems such as high-power lasers and optical fibre. Phase conjugate mirrors require a comparatively expensive and complex apparatus, as well as large quantities of power (as nonlinear optical processes can be efficient only at high enough intensities). However, phase conjugate mirrors have an inherently much greater accuracy in the direction of the retroreflection, which in passive elements is limited by the mechanical accuracy of the construction.

    Applications Retroreflectors on roads Retroreflection (sometimes called retroflection) is used on road surfaces, road signs, vehicles and clothing (large parts of the surface of special safety clothing, less on regular coats). When the headlights of a car illuminate a retroreflective surface, the reflected light is directed towards the car and its driver, and not wasted by going in all directions as with diffuse Reflection (physics). However, a pedestrian can see a retroreflective surface in the dark only if there is a light source directly between them and the reflector, e.g. a torch they carry, or directly behind them, e.g. a car approaching from behind. "Cat's eye (road)" are a particular type of retroreflector embedded in the road surface, used mostly in the UK and southern parts of the United States.

    Corner reflectors are better at sending the light back to the source over long distances, while spheres are better at sending the light to a receiver somewhat off-axis from the source, as when the light from headlights is reflected into the driver's eyes.

    Retroreflectors can be embedded in the road (level with the road surface), or can be raised above the road surface. raised pavement marker are visible for a very long distance (typically 0.5-1 kilometer or more), while sunken reflectors are only visible at very close range due to the higher angle required to properly reflect the light. Raised reflectors are not generally used in areas that regularly experience snow during winter, as passing snowplows will tear them off the roadway. The stress on the roadway caused by cars running over any embedded objects also contributes to accelerated wear and pothole formation.

    Retroreflective road paint is thus very popular in Canada and increasingly the northern parts of the United States, as it is not affected by the passage of snowplows and does not affect the interior of the roadway. Where weather permits, embedded retroreflectors are preferred as they last much longer than road paint, which is weathered by the elements and ground away by the passage of vehicles.

    Retroreflectors used in motorcycle safety Conspicuity, or visibility as outlined by The Motorcycle Safety Foundation greatly increases a motorcyclist's chances of being seen by motorists at night. Placing retroreflective patches on clothing and helmets greatly increases the visibility of bikers and pedestrians to oncoming motorists.

    Many materials appear to have some small degree of reflectivity, but retroreflective materials bounce the greatest amount of light back toward a light source. This makes them especially visible in dark conditions. Some patches claim to be reflective, but only retroreflective materials can be seen from more than a few feet away at night. Retroreflectivity of materials is measured in candle power. Official data says that white clothing performs up to 0.3 candle power. A vehicle license plate comes in at a level of 50. A conforming retro-reflective material has 500 candle power. There is a direct relationship between reflective index (candle power), and the distance from which it can be seen.

    Retroreflectors on the Moon The Apollo 11, Apollo 14, and Apollo 15 missions left retro-reflectors on the Moon as part of the Lunar Laser Ranging Experiment. They are commonly considered to be one of the strongest pieces of evidence against a Apollo moon landing hoax accusations. Additionally the unmanned Soviet Lunokhod 1 and Lunokhod 2 rovers carried smaller arrays. Reflected signals were initially received from Lunokhod 1, but no return signals have been detected since 1971, at least in part due to some uncertainty in its location on the Moon. Lunokhod 2's array continues to return signals to Earth. Even under good viewing conditions, only a single reflected photon is received every few seconds. This makes the job of filtering laser-generated photons from naturally-occurring photons challenging.

    Retroreflectors in Earth orbit LAGEOS, or Laser Geodynamics Satellites, are a series of scientific research satellites designed to provide an orbiting laser ranging benchmark for geodynamical studies of the Earth. There are two LAGEOS spacecraft, LAGEOS-1 launched in 1976, and LAGEOS-2 launched in 1992. As of 2004, both LAGEOS spacecraft are still in service.

    Retroreflectors and invisibility Retroreflective clothing, combined with a properly set up camera and projector, can be used to achieve the effect of partial invisibility when viewed from a single direction.

    More from BBC:

    Howstuffworks has a good article on invisibility cloaks which are based on retroreflectors. See

    Retroreflectors and communications Modulated retroreflectors, in which the reflectance is changed over time by some means, are the subject of research and development for free-space optical communications networks. The basic concept with such systems is that a low-power remote system, such as a sensor mote, can receive an optical signal from a base station and reflect the modulated signal back to the base station. Since the base station supplies the optical power, this allows the remote system to communicate without excessive power consumption. Modulated retroreflectors also exist in the form of modulated phase-conjugate mirrors (PCMs). In the latter case, a "time-reversed" wave is generated by the PCM, with temporal encoding of the phase-conjugate wave (see, e.g., reference 6).

    Cheap plastic corner retroreflectors are using as an aiming device in user-controlled technology optical datalink device RONJA. The aiming is done in night and the necessary retroreflector area depends on aiming distance and ambient lighting from street lamps. The optical receiver itself behaves as a weak retroreflector, because contains a large precisely focused lens (optics) and shiny object in the focal plane. This allows aiming without a retroreflector for short range.

    Retroreflectors and surveying In surveying with a total station or robot, the instrument man or robot aims a laser beam at a corner cube retroreflector held by the rodman. The instrument measures the propagation time of the light and converts it to a distance.

    Retroreflectivity used to detect digital cameras The sensor system of common (non-SLR) digital cameras is retroreflective. Researchers have used this property to demonstrate a system to prevent unauthorized photographs by detecting digital cameras and beaming a highly-focused beam of light into the lens.

    Other uses

    References

    External links



    Retroreflector - Wikipedia, the free encyclopedia
    A retroreflector is a device or surface that reflects light back to it's source with a minimum scattering of light. An electromagnetic wave front is reflected back along a vector ...

    Cat's Eye - Wikipedia, the free encyclopedia
    Cat's Eye can refer to: The visual organ of a cat; Chatoyancy, the reflective property of certain gems; Turbo smaragdus, a sea snail endemic to New Zealand; The operculum of ...

    Retroreflector Array Transfer Functions
    Retroreflector Array Transfer Functions by David A. Arnold 94 Pierce Road Watertown, MA 02472-3035 617-924-6812 Contents 1. Introduction 2. Diffraction patterns of single cube ...

    Retroreflector Array Transfer Functions
    Retroreflector Array Transfer Functions. by. David A. Arnold. 94 Pierce Road. Watertown, MA 02472-3035. 617-924-6812 . Contents . 1. Introduction. 2. Diffraction patterns of single ...

    MI-series Miniature Retroreflector interferometers
    MI-series Miniature Retroreflector interferometers The MI series systems are miniature interferometers equipped with triple-faceted retroreflectors for precision length measurement ...

    Linear (retroreflector) system
    Renishaw's RLE laser interferometer-based linear encoder system ... Linear RLE systems comprise an RLU laser unit and (generally) RLD10 detector head(s) configured for use with ...

    Retroreflector
    Last modified: Tue Oct 19 18:13:38 BST 2004

    Apollo 11 Laser Ranging Retroreflector Experiment
    Science Experiments - Laser Ranging Retroreflector. The Laser Ranging Retroreflector experiment was deployed on Apollo 11, 14, and 15. It consists of a series of corner-cube ...

    Microactuated Spherical Retroreflector for Free Space Communication
    Microactuated Spherical Retroreflector for Free Space Communication. Colin Jenkins, Walter Johnstone, Deepak Uttamchandani. This work is concerned with the development of a free ...

    The Most Important Thing Armstrong Left on the Moon
    ... by footprints, sitting in the moondust, lies a 2-foot wide panel studded with 100 mirrors pointing at Earth: the "lunar laser ranging retroreflector ...

     

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