Convex spherical mirrors bulge out toward the light source, with a curve that resembles the exterior of a sphere. Images formed with these mirrors will always be virtual, reduced in side and right side up.

12 filter

We also manufacture high performance ultra-broadband metallic mirrors. Here the substrate is coated first with a reflective metal film and then with a dielectric overcoat. Our metallic coatings include aluminum, silver, or gold. Gold is ideal when working in infrared applications, especially at wavelengths greater than 2 micron.  Silver has high reflectance over the visible and near infrared range. For a general purpose visible range, an aluminum coating performs well. The final dielectric coating provides protection and enhances reflectivity, and these mirrors are highly durable.

Spherical mirrors with concave surfaces may be used to form either real or virtual images, depending on the placement of the light source. These mirrors curve inward. They are ideal for focusing light to a single point.

Our parabolic mirrors are designed to reflect energy from a single point outwards, or to capture all parallel incoming rays and reflect to a single focal point. They have many applications including laser material processing, fluorescence microscopy, high harmonic generation, and super continuum generation without wave guides.

What is a Wratten filter

Optical mirrors are precision optics with a highly polished plane or curved surface which reflects light.  At Shanghai Optics we manufacture custom optical mirrors for a wide range of applications. Life Sciences, astronomy, metrology, and solar engineering are only a few of the industries which depend on our precision mirrors and other optical components.

Focal length is measured as the distance from the mirror to the focal point; the point at which parallel waves converge. For a concave mirror, focal length will be positive; for a convex mirror, negative.

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Size and shape are quantified by diameter, thickness, focal length, and radius of curvature. Diameter is measured straight on, and the radius of curvature is measured as if the mirror’s curvature was extrapolated into a sphere. The thickness of a mirror is measured in two places: at the center and at the edge.

Wratten filter chart

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Air Chief Marshal Sir William John Wratten, GBE, CB, AFC (born 15 August 1939) is a retired senior commander in the Royal Air Force who was Air Officer Commanding-in-Chief of RAF Strike Command from 1994 to 1997.

All mirrors can be categorized as second surface or front surface mirrors. A second surface mirror is a standard mirror with the coating on the back side of glass or other transparent material. A front surface mirror, with the reflective coating on the front side, gives a more exact reflection with no double image. These mirrors are often a good choice for engineering applications because of the accuracy of the reflected image.

Wratten meaning

In 1995, following the Chinook Helicopter Crash on the Mull of Kintyre, Wratten was the Senior Reviewing Officer of the Board of Inquiry which had failed to find a cause of the accident. Despite a lack of Accident Data Recorder and cockpit voice recorder, Wratten concluded that because the aircraft hit the ground whilst in cloud/fog, pilot error was the cause of the crash and found the pilots guilty of gross negligence.[3] Following a subsequent Scottish Fatal Accident Inquiry and House of Commons Public Accounts Committee report, a House of Lords Select Committee was appointed to consider all the circumstances surrounding the crash and unanimously concluded "that the reviewing officers were not justified in finding that negligence on the part of the pilots caused the aircraft to crash".[4]

Wratten filter for slit lamp

Hot and cold mirrors are both specialized dielectric mirrors which are used for heat control; to filter unwanted energy from a light source.  A cold mirror will reflect 90% of the visible light spectrum while efficiently transmitting (and thus removing from the site of interest) infrared wavelengths.  A hot mirror will reflect 90% of infrared and near infrared light, and transmit a large portion of visible light (up to 80%).  Shanghai Optics can manufacture hot and cold mirrors for any angle of incidence desired, from 0 to 45 degrees.

Wratten

Our state of the art machinery allows us to manufacture high quality mirrors designed to reflect a certain wavelength range while allowing light transmission in other wavelengths. Custom optical mirrors and precision reflectors can also be designed to reflect at pre-specified angles.

Educated at Chatham House Grammar School in Ramsgate, Wratten entered RAF Cranwell and was commissioned into the Royal Air Force in 1960.[1] He was appointed Officer Commanding No. 23 Squadron in 1975 and, following his promotion to group captain, he became Station Commander at RAF Coningsby in 1980.[1] In June 1982 he was made the first Station Commander at RAF Stanley in the Falkland Islands after the 1982 war.[1] He went on to serve as Director of Operational Requirements (Air) at Ministry of Defence in 1983, as Senior Air Staff Officer at Headquarters No. 1 Group in 1986 and as Air Officer Commanding No. 11 Group in 1989.[1] As an air vice marshal, he was Air Commander British Forces Middle East from 17 November 1990 until the end of the Gulf War (as such he was the senior air force officer in Operation Granby).[1] His last appointment was as Air Officer Commanding Strike Command in 1994 before he retired in 1997.[2]

Our broadband dielectric mirrors are ideal for demanding applications.  Durable and stable, they offer near total reflection over wide spectral ranges (up to 100s of nanometers) and can be used over wide angles of incidence. These mirrors are resistant to environmental or laser damage and are suitable for visible, NIR, and UV light.

Right angle mirrors are made from right angle prisms, with a special metallic coating on the hypotenuse of the prism. These mirrors are ideal for system alignment, being easily mounted.  They reflect light back at a 90 degree angle.  Right angle mirrors are also known as turning mirrors.

For applications with a specific, narrow wavelength and higher energy levels, we recommend laser line mirrors.  These highly efficient precision mirrors can be used for beam-steering in laser applications. Our laser line mirrors can be customized for your specific laser beam type or wavelength, and we offer dielectric coatings that can be optimized for high reflectivity at your laser wavelength of choice.

The damage threshold of an optical mirror is the highest energy that the mirror can withstand without damage. For instance, if a damage threshold is given as 3.00 J/cm2 (522 nm, 10 ns pulse, 10 Hz, Ø0.803 mm) that optic should be able to withstand energy up to 3.00 J/cm2 at (522 nm, 10 ns pulse, 10 Hz, Ø 0.803 mm). It is important to realize that if optics are not properly cared for, dirt and contamination can lower the damage threshold.

Broadband metallic mirrors also offer high reflection over a broad spectral range. They are easy to set up, being insensitive to angle of incidence and polarization. We often recommend these coated mirrors as a good combination of performance and value.

We offer a wide range of mirror coatings, including aluminum, silver, gold, copper, and dielectric. Selecting the right reflective coating for your application will ensure high reflectivity for your target wavelength.

Wratten filter optometry

An off-axis parabolic mirror can be considered to be a “cut out” from a larger parent parabolic mirror. These mirrors are a bit more difficult to align, but when properly set up can be extremely helpful in optical design. They exhibit many of the same features as parabolic mirrors, but will deviate light off-axis. This allows for more interactive space around the focal point.

Surface quality is quantified with a scratch-dig number, and the lower the scratch-dig number, the better the surface quality.