Product Overview
Newport 40D04 AL.2 Round Mirror 4 Inch, ƛ/2, 250-600nm - Unused, Never Opened, NOS
This listing is for a Newport 40D04AL.2 round optical mirror with a 4.0-inch (101.6 mm) diameter, built on a Borofloat® 33 substrate and finished with a UV-enhanced aluminum AL.2 coating.
Decoding the Newport product code (with more than a little help from Google Gemini), we confirmed diameter, substrate, coating range, and flatness indicators. The AL.2 coating achieves over 90% reflectivity from 250 to 600 nm, featuring a protective dielectric overcoat. Packaging specifies surface flatness of λ/2 (half-wave) at a standard test wavelength of 632.8 nm, whereas the part coding suggests a possible λ/4 (quarter-wave) flatness. The minimum assured is λ/2, with potentially tighter performance depending on the production batch.
Product Condition
Unused, new old stock. The packaging appears to have never been opened and has been kept in its original condition.
Product Overview
Newport optics are widely used in spectroscopy benches, laser alignment, and UV setups. Borofloat 33 offers low thermal expansion and mechanical stability, while the AL.2 UV-enhanced aluminum coating provides high reflectivity in the UV and visible bands. The 4-inch format supports larger beam paths and offers flexible mounting options.
Key Features
- Brand: Newport
- Model: 40D04AL.2
- Diameter: 4.0 in (101.6 mm)
- Substrate: Borofloat® 33 borosilicate glass
- Coating: AL.2 UV-enhanced aluminum with dielectric overcoat
- Spectral performance: over 90% reflectivity from 250 to 600 nm
- Surface flatness: specified λ/2 (half-wave) at 632.8 nm; part code indicates possible λ/4 (quarter-wave)
- Dielectric overcoat helps resist oxidation
- Packaging status: appears never opened (preserved NOS)
Applications
- UV and visible laser beam steering and alignment
- Spectroscopy and optical testing
- Research labs and teaching optics
- Prototype optical instruments and fixtures
- Replacement for Newport optical mounts and systems
- Custom assemblies requiring high UV reflectivity
Frequently Asked Questions
Is λ/4 a quarter-wave or a half-wave?
λ/4 is a quarter-wave and is tighter. λ/2 is a half-wave and is looser compared to λ/4. This mirror is labeled λ/2 on the box; the part code suggests a possible λ/4.
What does the AL.2 coating provide?
UV-enhanced aluminum optimized for 250 to 600 nm with over 90% reflectivity and a protective dielectric overcoat to limit oxidation.
Is the substrate Pyrex or Borofloat®?
The box mentions Pyrex, but decoding aligns with Borofloat® 33. Both are borosilicate glasses; Borofloat® is commonly selected for optical flatness and stability.
Has the item been opened or handled?
The packaging appears never opened and has been kept in its original packaging with no signs of prior use.
What size mounts does this fit?
Diameter is 4.0 inches (101.6 mm). Verify your mount’s clear aperture and retention method for a proper fit.
A never-opened Newport optic is uncommon. Precision kept in its box until now, this mirror is ready to step into your setup - its next chapter belongs to you.
