supermirrors (original) (raw)

Definition: laser mirrors with a very high reflectivity

Alternative term: ultra-high-reflectivity mirrors

Category: photonic devices

• mirrors
  • metal-coated mirrors
  • dielectric mirrors
  • dispersive mirrors
  • Bragg mirrors
  • crystalline mirrors
  • first surface mirrors
  • parabolic mirrors
  • variable reflectivity mirrors
  • deformable mirrors
  • laser mirrors
  • laser line mirrors
  • fiber loop mirrors
  • semiconductor saturable absorber mirrors
  • supermirrors
  • (more topics)

Related: mirrorsdielectric mirrorscrystalline mirrorsFabry–Pérot interferometersfinesseQ-factor

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DOI: 10.61835/w54 Cite the article: BibTex BibLaTex plain textHTML Link to this page! LinkedIn

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📦 For purchasing supermirrors, use the RP Photonics Buyer's Guide — an expert-curated directory for finding all relevant suppliers, which also offers advanced purchasing assistance.

What are Supermirrors?

An optical supermirror (or ultra-high-reflectivity mirror) is a Bragg mirror (typically a dielectric mirror) that is optimized for an extremely high reflectance — in extreme cases, larger than 99.9999%. This means that the reflection losses are below 1 ppm. Two such ultra-high reflectance mirrors form a Fabry–Pérot interferometer with a finesse larger than 3 million and a strong field enhancement within the cavity. The Q-factor of a supermirror cavity can be above 1011.

Although most supermirrors are dielectric mirrors (often with Ta2O5/SiO2 layers made by ion beam sputtering), there are also crystalline mirrors [6] with very high peak reflectivities of e.g. 99.9997% [7].

Supermirrors can be used in certain quantum optics experiments and for some measurements with extremely high precision, e.g. involving high-finesse interferometers or optical gyroscopes.

The term supermirror is also common for X-ray and neutron reflectors. In that field, it was originally very difficult to achieve high reflectance values. Multilayer mirrors have then been developed, which offer much better performance. Still, the achieved peak reflectivities are far lower in this regime, compared with optical supermirrors.

Frequently Asked Questions

This FAQ section was generated with AI based on the article content and has been reviewed by the article’s author (RP).

What is an optical supermirror?

An optical supermirror is a type of Bragg mirror, typically a dielectric mirror, that is optimized for an extremely high reflectance, often exceeding 99.999%. This corresponds to reflection losses of only a few parts per million (ppm).

What are supermirrors used for?

Is the term 'supermirror' also used for other types of optics?

Yes, the term is also used for X-ray and neutron reflectors. However, those multilayer mirrors operate in a different spectral region and achieve significantly lower peak reflectivities than optical supermirrors.

Suppliers

Sponsored content: The RP Photonics Buyer's Guide contains nine suppliers for supermirrors. Among them:

⚙ hardware

So-called supermirrors for ring laser gyroscope assemblies or certain scientific applications require coated optics with extremely low losses (i.e. absorption and scattering). These mirrors also have a maximum reflectivity with R > 99.998% and total losses < 10 ppm.

LASEROPTIK uses a modified IBS machine that is capable to produce coatings on super­polished substrates. The cleanliness of the machine and environment is maintained in a dedicated super-clean room, where also the extensive substrate pre- and after-treatment takes place.

Measurement devices such as white light profilometers and high resolution microscopes (up to × 1000) for the inspection procedures are in place. A custom built cavity ring-down setup allows to determine the reflection with a precision of up to four decimal places and to refer back to the losses.

⚙ hardware

UltraFast Innovations (UFI®) manufactures supermirrors with a reflectivity exceeding 99.99%. Our magnetron sputtering facility offers the best technology for ultra-high reflection mirrors due to the extremely dense layers. More than 99.997% reflection over a bandwidth of 200 nm or more is available.

Characterization of these mirrors is performed in a cavity ring-down measurement device with ppm-level precision.

⚙ hardware

Thorlabs manufactures high-performance, single-crystal supermirror coatings on Ø1" substrates for applications requiring the highest reflectance possible at a specific wavelength. These high-performance supermirrors with ultralow optical absorption and minimal Brownian noise are key ingredients for the construction of optical atomic clocks, optical reference cavities, and stabilized lasers, as well as the next generation of gravitational wave detectors.

⚙ hardware

OPTOMAN's extreme low-loss mirrors have a maximum reflectivity of R > 99.995% and total losses (absorption, scatter, and transmission) below 1 ppm at a discrete wavelength and angle of incidence. Coatings are applied on high purity fused silica substrates (plane, spherical or wedged) super-polished to an RMS roughness of <2 Å. Mirrors are available with a CRD measurement that prove reflectivity and loss values.

Bibliography

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