The Protected Gold Mirror Explained for 3D Scanning & Structured Light Engineers

Optical designers sometimes treat mirrors as simple parts, yet in 3D Scanning & Structured Light the mirror decides beam direction, loss budget and even image contrast.…

Optical designers sometimes treat mirrors as simple parts, yet in 3D Scanning & Structured Light the mirror decides beam direction, loss budget and even image contrast. The Protected Gold Mirror is a quietly critical component whose details repay careful attention.

At its core, the Protected Gold Mirror is a silicon, copper or glass element carrying a protected gold. That stack is engineered to return incident light efficiently over 700 nm to 10.6 µm, giving designers a predictable, low-loss way to steer a beam where they need it.

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.

Most of the engineering in a Protected Gold Mirror lives in its protected gold. The stack is designed for 700 nm to 10.6 µm and delivers 98%+ in the IR, and its environmental protection layer keeps the metal from tarnishing so the mirror keeps working year after year.

Substrate choice for a Protected Gold Mirror is a trade between optical grade and budget. silicon, copper or glass is a common pick because it can be cut and polished to λ/4 flatness and a 40-20 surface, which is plenty for the reflection quality most 3D Scanning & Structured Light systems require.

When you specify a Protected Gold Mirror, the numbers that matter are flatness λ/4, finish 40-20, and the reflectance 98%+ in the IR across 700 nm to 10.6 µm. Thickness 0.5–6 mm is mostly about handling and mount compatibility, but it still belongs on the print. The specification table covers the common configurations.

Most 3D Scanning & Structured Light engineers reach for a Protected Gold Mirror when they need projecting and capturing patterned light accurately. The component's job is unglamorous but essential — keep the light on course and the loss low.

Behind the performance

What reads on a datasheet as "98%+ in the IR over 700 nm to 10.6 µm" is really the outcome of interference. The protected gold on a silicon, copper or glass base is built layer by layer so reflected waves reinforce. Flatness λ/4 then keeps that wavefront from bending. The physics is old; the discipline to repeat it is the hard part.

Selecting a Protected Gold Mirror for 3D Scanning & Structured Light starts with the wavelength and angle of incidence, then the acceptable loss. Match the protected gold to 700 nm to 10.6 µm, confirm 98%+ in the IR, and make sure the silicon, copper or glass and 0.5–6 mm fit the mount you already have. The spec and size tables make that comparison quick.

A Protected Gold Mirror is tougher than it looks but softer than you think. Fingerprints on the protected gold are the usual cause of field failures, so edge-handling and capped storage pay off. A little discipline keeps 98%+ in the IR where it belongs.

Because we control cutting, coating and finishing in one place, a Protected Gold Mirror can move from your drawing to a finished part without hand-offs. The silicon, copper or glass is cut to ±0.01 mm, the protected gold is vacuum-deposited for 98%+ in the IR over 700 nm to 10.6 µm, and the result is inspected to λ/4 flatness and 40-20 quality.

Durability is part of the spec, not an afterthought. For 3D Scanning & Structured Light the Protected Gold Mirror should survive shipping, installation and the occasional wipe. The protective overcoat on the protected gold is what lets it do that without losing 98%+ in the IR over time.

A word on installation

When fitting a Protected Gold Mirror into 3D Scanning & Structured Light hardware, handle it by the edges, seat it against a clean flat, and torque gently. Stress on the silicon, copper or glass shifts the figure and costs you the very flatness (λ/4) you paid for.

Coating a Protected Gold Mirror means laying down a protected gold whose optical thickness is controlled to a fraction of a wavelength. Done well, the part holds 98%+ in the IR over 700 nm to 10.6 µm; done carelessly, it drifts and the system loses light it cannot afford to lose.

One term worth knowing

"Reflectivity" on a Protected Gold Mirror is the fraction of incident light returned by the protected gold. Quoting 98%+ in the IR without the band (700 nm to 10.6 µm) is meaningless, because the same coating can be excellent at one wavelength and poor at another — always pair the number with the range.

At its core, the Protected Gold Mirror is a silicon, copper or glass element carrying a protected gold. That stack is engineered to return incident light efficiently over 700 nm to 10.6 µm, giving designers a predictable, low-loss way to steer a beam where they need it.

When you specify a Protected Gold Mirror, the numbers that matter are flatness λ/4, finish 40-20, and the reflectance 98%+ in the IR across 700 nm to 10.6 µm. Thickness 0.5–6 mm is mostly about handling and mount compatibility, but it still belongs on the print. The specification table covers the common configurations.

The working principle is the law of reflection applied to a coated plane. Mount the Protected Gold 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 3D Scanning & Structured Light.

Quick terminology

"Flatness λ/4" describes how close the surface is to a perfect plane, in fractions of a wavelength. Tighter flatness costs more but protects wavefront quality, which is why 3D Scanning & Structured Light systems specify it explicitly rather than leaving it to chance.

A practical Protected Gold Mirror datasheet reads: silicon, copper or glass substrate, λ/4 flatness, 40-20 quality, 0.5–6 mm thick, 98%+ in the IR over 700 nm to 10.6 µm. Those five lines settle most design reviews for 3D Scanning & Structured Light. See the standard size list for what we stock and what we cut to order.

For 3D Scanning & Structured Light, do not over-specify. Choose the protected gold that covers 700 nm to 10.6 µm at the angle you use, keep flatness at λ/4 unless the wavefront demands more, and you will have a Protected Gold Mirror that is both capable and economical.

Quick terminology

"Flatness λ/4" describes how close the surface is to a perfect plane, in fractions of a wavelength. Tighter flatness costs more but protects wavefront quality, which is why 3D Scanning & Structured Light systems specify it explicitly rather than leaving it to chance.

Substrate choice for a Protected Gold Mirror is a trade between optical grade and budget. silicon, copper or glass is a common pick because it can be cut and polished to λ/4 flatness and a 40-20 surface, which is plenty for the reflection quality most 3D Scanning & Structured Light systems require.

In short

For 3D Scanning & Structured Light, the Protected Gold Mirror is less a commodity than a tuned component. Specify the band (700 nm to 10.6 µm), the reflectivity (98%+ in the IR) and the figure (λ/4), 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.