UV Mirror or a second-surface mirror for Optical Metrology & Interferometry? A Selection Note

Every Optical Metrology & Interferometry system eventually meets the same question: where does the light go, and how much of it survives the turn? A well-specified UV…

Every Optical Metrology & Interferometry system eventually meets the same question: where does the light go, and how much of it survives the turn? A well-specified UV Mirror answers both, which is why it earns a place on the bill of materials long before the enclosure is drawn.

At its core, the UV Mirror is a fused silica or calcium fluoride element carrying a UV-enhanced dielectric or aluminum. That stack is engineered to return incident light efficiently over 193–400 nm, giving designers a predictable, low-loss way to steer a beam where they need it.

The working principle is the law of reflection applied to a coated plane. Mount the UV Mirror at 45° and a beam turns 90°; stack several and you fold a long path into a short box. That simplicity is why mirrors remain the fastest way to route light in Optical Metrology & Interferometry.

Most of the engineering in a UV Mirror lives in its UV-enhanced dielectric or aluminum. The stack is designed for 193–400 nm and delivers > 90% in the UV, and its environmental protection layer keeps the metal from tarnishing so the mirror keeps working year after year.

A UV Mirror starts as a fused silica or calcium fluoride blank. We hold it to λ/10 flatness and 20-10 surface quality, then apply the UV-enhanced dielectric or aluminum. The substrate never sees the beam directly, but its figure sets the limit on how straight the reflected wavefront stays.

When you specify a UV Mirror, the numbers that matter are flatness λ/10, finish 20-10, and the reflectance > 90% in the UV across 193–400 nm. Thickness 1–5 mm is mostly about handling and mount compatibility, but it still belongs on the print. The specification table covers the common configurations.

Where comparing wavefronts to a reference with sub-wavelength accuracy, a UV Mirror earns its place by doing one job reliably: turning the beam without adding noise. In Optical Metrology & Interferometry that reliability is the difference between a prototype and a shippable product. More application examples are worth a look if the use case is close to yours.

Choosing among options

Within the mirror family, the UV Mirror trades some peak reflectance for bandwidth and price. If Optical Metrology & Interferometry demands the very highest reflectivity at one wavelength, a dielectric part wins; if it needs > 90% in the UV across 193–400 nm at sensible cost, the UV Mirror with its UV-enhanced dielectric or aluminum is the pragmatic choice.

Selecting a UV Mirror for Optical Metrology & Interferometry starts with the wavelength and angle of incidence, then the acceptable loss. Match the UV-enhanced dielectric or aluminum to 193–400 nm, confirm > 90% in the UV, and make sure the fused silica or calcium fluoride and 1–5 mm fit the mount you already have. The spec and size tables make that comparison quick.

Mirrors reward careful handling. Hold a UV Mirror by the edges, keep the coated face away from fingers and aerosols, and clean only with approved optics tissue and solvent when truly needed. Store it in its packaging, coated face protected, and it will hold > 90% in the UV for years.

At JYOPTO we make UV Mirror parts by cutting fused silica or calcium fluoride with laser accuracy of ±0.01 mm, then applying the UV-enhanced dielectric or aluminum under vacuum. Standard blanks run 1–5 mm thick, edges are smoothed for safe handling, and every shipped mirror meets λ/10 flatness with a 20-10 surface — the same disciplines we apply across our optical glass, vacuum-coating and precision cold-processing lines since 2020.

A word on installation

When fitting a UV Mirror into Optical Metrology & Interferometry hardware, handle it by the edges, seat it against a clean flat, and torque gently. Stress on the fused silica or calcium fluoride shifts the figure and costs you the very flatness (λ/10) you paid for.

Most of the engineering in a UV Mirror lives in its UV-enhanced dielectric or aluminum. The stack is designed for 193–400 nm and delivers > 90% in the UV, and its environmental protection layer keeps the metal from tarnishing so the mirror keeps working year after year.

Substrate choice for a UV Mirror is a trade between optical grade and budget. fused silica or calcium fluoride is a common pick because it can be cut and polished to λ/10 flatness and a 20-10 surface, which is plenty for the reflection quality most Optical Metrology & Interferometry systems require.

Because we control cutting, coating and finishing in one place, a UV Mirror can move from your drawing to a finished part without hand-offs. The fused silica or calcium fluoride is cut to ±0.01 mm, the UV-enhanced dielectric or aluminum is vacuum-deposited for > 90% in the UV over 193–400 nm, and the result is inspected to λ/10 flatness and 20-10 quality.

For Optical Metrology & Interferometry, do not over-specify. Choose the UV-enhanced dielectric or aluminum that covers 193–400 nm at the angle you use, keep flatness at λ/10 unless the wavefront demands more, and you will have a UV Mirror that is both capable and economical.

At JYOPTO we make UV Mirror parts by cutting fused silica or calcium fluoride with laser accuracy of ±0.01 mm, then applying the UV-enhanced dielectric or aluminum under vacuum. Standard blanks run 1–5 mm thick, edges are smoothed for safe handling, and every shipped mirror meets λ/10 flatness with a 20-10 surface — the same disciplines we apply across our optical glass, vacuum-coating and precision cold-processing lines since 2020.

Reflection on a first surface is straightforward physics: photons strike the coated face and are returned according to the law of reflection, angle in equals angle out. Because the coating sits on top, there is no second surface behind it to create a faint ghost image, which matters whenever contrast or measurement accuracy is at stake.

At JYOPTO we make UV Mirror parts by cutting fused silica or calcium fluoride with laser accuracy of ±0.01 mm, then applying the UV-enhanced dielectric or aluminum under vacuum. Standard blanks run 1–5 mm thick, edges are smoothed for safe handling, and every shipped mirror meets λ/10 flatness with a 20-10 surface — the same disciplines we apply across our optical glass, vacuum-coating and precision cold-processing lines since 2020.

The UV Mirror is not exclusive to Optical Metrology & Interferometry. Universities, service centers and R&D groups use it wherever a beam must turn, which makes a flexible, customizable part a quiet workhorse across the optics world.

In short

For Optical Metrology & Interferometry, the UV Mirror is less a commodity than a tuned component. Specify the band (193–400 nm), the reflectivity (> 90% in the UV) and the figure (λ/10), and you will spend less time debugging light you cannot see. That is the whole game. Where your application sits among the sectors we serve changes the details, not the method.