Asphericon ALL12-25-P-U Low-NA Aspheric Mirror, N-BK7, 12.5 mm Diameter, f/d = 2.0, Optimized for 780 nm

Overview

The Asphericon ALL12-25-P-U is a precision-engineered low-numerical-aperture aspheric mirror fabricated from high-homogeneity N-BK7 optical glass. Designed specifically for 780 nm laser systems—including Ti:sapphire oscillators, fiber-coupled diode lasers, and quantum optics setups—this uncoated (U) variant serves as a foundational optical element where custom or application-specific coatings are required. Its aspheric surface profile eliminates spherical aberration inherently, enabling diffraction-limited performance in collimation, focusing, and beam re-imaging applications without the need for multi-element correction. With an f/d ratio of 2.0 and NA of 0.25, the mirror provides long working distance and shallow convergence angle—ideal for spatial filtering, interferometric alignment, and low-divergence beam steering in compact optical architectures. Manufactured under strict ISO 10110-5 tolerancing, its RMS surface irregularity is controlled to ≤0.1 µm, ensuring wavefront fidelity critical for coherent imaging and ultrafast pulse preservation.

Key Features

• Precision aspheric surface with RMSi ≤ 0.1 µm, certified per ISO 10110-5 for wavefront stability
• N-BK7 substrate offering excellent transmission from 350 nm to 2.0 µm and superior thermal and mechanical stability
• Low NA (0.25) design optimized for minimal spherical and coma aberration in near-infrared beam paths
• Diameter tolerance: +0/−0.04 mm; center thickness tolerance: ±0.05 mm; clear aperture ≥ 90 % of physical diameter
• Surface quality rated 60–40 per MIL-PRF-13830B, suitable for Class 100 cleanroom integration
• Uncoated (U) version allows end-user deposition of specialized dielectric, V-coating, or ultra-low-LIDT-resistant layers
• RoHS-compliant manufacturing process with full traceability documentation available upon request

Sample Compatibility & Compliance

The ALL12-25-P-U is compatible with standard kinematic mounts (e.g., SM1-threaded lens tubes, Ø1/2″ post holders) and integrates seamlessly into OEM laser platforms requiring stable, low-aberration reflective optics. Its N-BK7 substrate exhibits negligible birefringence and low thermal expansion (7.1 × 10⁻⁶ K⁻¹), making it suitable for temperature-sensitive interferometers and cavity stabilization systems. The mirror conforms to ISO 9001-certified production protocols and meets EU Directive 2011/65/EU (RoHS 2) for hazardous substance restrictions. While uncoated, its surface polish supports subsequent thin-film coating via ion-beam sputtering or e-beam evaporation—fully compatible with ASTM F1742 (optical coating adhesion testing) and ISO 9211-3 (coating environmental durability standards). For regulated environments (e.g., medical laser devices or aerospace avionics), full material certificates (CoC), surface metrology reports (Zygo interferogram data), and batch-level LIDT verification can be supplied.

Software & Data Management

Asphericon provides downloadable technical datasheets, Zemax-compatible .ZAR and Code V .SEQ files, and STEP geometry models for system-level optical design integration. All StockOptics products—including the ALL12-25-P-U—are assigned unique serial numbers traceable to manufacturing logs, surface test records, and interferometric validation reports. While the mirror itself requires no embedded firmware or driver software, its metrology data (including PV error maps and power spectral density curves) can be imported into industry-standard analysis tools such as MATLAB, Python (using SciPy’s optics modules), or Synopsys LightTools for rigorous stray-light and MTF modeling. For customers operating under FDA 21 CFR Part 11 or ISO 13485 quality management systems, Asphericon supports audit-ready documentation packages including calibration certificates, environmental stress test summaries, and supplier qualification dossiers.

Applications

• Laser Physics & Ultrafast Optics: Mode-matching in Ti:sapphire amplifiers, pulse compressor gratings alignment, and cavity output coupler substrates
• Quantum Technology: Beam shaping for cold atom trapping (MOTs), optical lattice generation, and single-photon source coupling
• Biophotonics & Microscopy: High-NA-free illumination arms in structured illumination microscopy (SIM) and adaptive optics wavefront correction paths
• Industrial Sensing: Reference mirrors in fiber-optic gyroscopes, LIDAR receiver optics, and photothermal deflection systems
• Space-Qualified Systems: Passive optical elements in CubeSat payloads due to N-BK7’s radiation hardness and vacuum compatibility
• OEM Integration: Core component in compact spectrometers, OCT sample arms, and laser Doppler vibrometry heads

FAQ

Is this mirror suitable for high-power CW lasers at 780 nm?
The uncoated N-BK7 surface has inherent absorption limitations; for continuous-wave operation above 5 W, we recommend specifying a custom V-coating or high-LIDT dielectric stack. Contact our technical sales team for coated variants with verified LIDT > 25 J/cm² @ 780 nm, 10 ns.

Can I mount this mirror directly into a kinematic cage system?
Yes—the 12.5 mm outer diameter is compatible with SM1-threaded adapters and standard Ø1/2″ lens mounts. Centering accuracy is maintained within ±5 arcsec, supporting sub-micron alignment repeatability.

What metrology data is included with shipment?
Each unit ships with a certificate of conformance, interferometric surface map (Zygo GPI data), RMSi measurement report, and visual inspection record per ISO 10110-7.

Do you offer mounting options for this optic?
Yes—Asphericon offers pre-mounted versions (ALL12-25-P-M) with aluminum or stainless steel kinematic cells, kinematic tip/tilt adjustment, and optional magnetic base integration.

Is N-BK7 appropriate for UV or deep-IR extension beyond 780 nm?
N-BK7 transmits well from ~350 nm to 2.0 µm. For UV applications (2.0 µm, consider CaF₂ or ZnSe substrates—custom quotations available.