MiXran Meg1131 Calcium Fluoride (CaF₂) Positive Meniscus Lens

Overview

The MiXran Meg1131 is a precision-engineered calcium fluoride (CaF₂) positive meniscus lens designed for demanding mid-infrared (MIR) optical systems operating in the 3–5 µm spectral band. Unlike plano-convex or biconvex geometries, the positive meniscus configuration features both surfaces convex with the center thicker than the edge—optimized to minimize spherical aberration while maintaining compact beam shaping capability. CaF₂ is selected for its exceptional transmission from deep UV (180 nm) through visible and into the mid-IR (up to 8 µm), low thermo-optic coefficient (dn/dT ≈ –1.1 × 10⁻⁶ /°C), and high resistance to thermal shock—making it ideal for laser delivery, thermal imaging, FTIR spectrometers, and CO/CO₂ laser beam conditioning where chromatic stability and power handling are critical. The Meg1131 is fabricated using single-crystal CaF₂ substrates grown via the Bridgman method, ensuring homogeneity, low birefringence, and minimal scatter.

Key Features

• Precision-ground and polished CaF₂ substrate meeting ISO 10110-1 surface quality (60–40 scratch-dig) and ISO 10110-3 surface flatness (λ/4 @ 633 nm)
• Two standard diameter options: 12.7 mm and 25.4 mm, supporting integration into OEM modules and benchtop optical breadboards
• Eight discrete EFL variants (20 mm to 500 mm), each with fully characterized R₁, R₂, BFL, Tc, and Te—enabling accurate paraxial ray tracing and Zemax-compatible modeling
• Optional broadband anti-reflection coating (IR1) optimized for 3–5 µm with average reflectance <1.5% across the band; uncoated version available for UV–VIS–NIR flexibility
• High laser-induced damage threshold (LIDT) >500 MW/cm² (for 10 ns, 1064 nm pulses), validated per ISO 21254-1
• Thermally stable design: low dn/dT and CTE (~18.9 × 10⁻⁶ /°C) ensure minimal focal shift under ambient fluctuation

Sample Compatibility & Compliance

The Meg1131 is compatible with standard SM1 (1.035″-40) and SM25 (2.5″-40) lens mounts, and its 30 arcmin wedge tolerance ensures alignment compatibility in multi-element assemblies. All lenses undergo full metrology verification—including interferometric surface figure (Zygo GPI), spectral transmittance (PerkinElmer Lambda 950), and dimensional inspection (Mitutoyo Coordinate Measuring Machine). Manufacturing adheres to ISO 9001:2015 quality management protocols. While not certified to FDA or IEC 61000 standards (as a passive optical component), documentation supports traceability to NIST-traceable calibration artifacts and conforms to MIL-PRF-13830B for defect classification. Full test reports—including spectral curves, surface maps, and coating performance data—are provided with each shipment for GLP/GMP-compliant laboratories.

Software & Data Management

No embedded firmware or proprietary software is required—Meg1131 functions as a passive optical element. However, comprehensive technical data is delivered in machine-readable formats: Zemax (.zmx) and CODE V (.seq) files for all configurations are available upon request; spectral transmittance data is supplied in CSV format (wavelength in nm, %T); and mechanical drawings comply with ASME Y14.5-2018 GD&T standards. For customers integrating into automated optical alignment systems, STEP AP214 (.stp) models support CAD interoperability. All product identifiers (e.g., GLM5-025B-100-IR1) are structured to enable ERP/MES integration and lot-level traceability in regulated environments.

Applications

• Mid-wave infrared (MWIR) imaging systems: collimation and focusing optics for cooled InSb and HgCdTe detectors
• Gas sensing platforms: beam expansion and relay optics in tunable diode laser absorption spectroscopy (TDLAS) at 3.3–3.5 µm (CH₄, C₂H₂)
• Laser material processing: focusing optics for pulsed CO lasers (5.3–5.6 µm) and HF/DF chemical lasers
• Fourier-transform infrared (FTIR) spectrometers: relay lenses in interferometer arms and detector coupling optics
• UV–VIS–IR broadband instrumentation: uncoated versions serve as achromatic condenser elements in synchrotron beamlines
• Space-qualified optical subsystems: heritage CaF₂ material used in JAXA and ESA planetary IR sensors due to radiation hardness and vacuum stability

FAQ

Is the Meg1131 suitable for high-power CW CO₂ laser applications?
No—CaF₂ exhibits strong absorption above 7 µm; for 10.6 µm CO₂ lasers, ZnSe or GaAs lenses are recommended. Meg1131 is strictly intended for 3–5 µm operation.

Can I specify custom diameters or focal lengths?
Yes—MiXran offers custom fabrication under NRE agreement. Minimum order quantity applies; lead time extends to 8–12 weeks for non-standard geometries.

What is the maximum operating temperature before thermal degradation?
CaF₂ maintains structural integrity up to 800°C in inert atmosphere; however, for optical performance stability, continuous operation above 200°C is not recommended without thermal modeling.

Do IR1-coated lenses require special cleaning procedures?
Yes—use only spectroscopic-grade acetone and methanol with Class 100 cleanroom swabs; avoid ultrasonic cleaning or abrasive wipes to preserve coating adhesion and LIDT.

Are Zemax files provided for all EFL variants?
Yes—Zemax Physical Optics Propagation (POP) files and sequential raytrace models are included in the technical package for every standard SKU.