MiXran Meg1025 Calcium Fluoride (CaF₂) Double-Convex Lens

Overview

The MiXran Meg1025 is a precision-engineered calcium fluoride (CaF₂) double-convex lens designed for demanding mid-infrared (MIR) optical systems operating in the 3–5 µm spectral range. Fabricated from high-purity, low-OH synthetic CaF₂ crystal, this lens exhibits exceptional transmission (>95% per surface, uncoated) across the 0.18–8.0 µm band, with minimal absorption and negligible fluorescence—critical for thermal imaging, laser delivery, FTIR spectroscopy, and quantum cascade laser (QCL) beam conditioning. Its symmetric biconvex geometry (R₁ = R₂) ensures balanced wavefront error and reduced spherical aberration when used at finite conjugates near unity magnification. The lens is manufactured to ISO 10110-1 surface quality specifications (scratch-dig 20–10), λ/4 surface flatness tolerance, and ±0.2% focal length accuracy—enabling predictable paraxial performance in alignment-critical setups.

Key Features

• High-transmission CaF₂ substrate with intrinsic radiation hardness and low thermal expansion coefficient (18.9 × 10⁻⁶ K⁻¹), ensuring stability under thermal cycling and high-fluence MIR illumination
• Two coating variants: uncoated for maximum UV-VIS-NIR versatility or IR1 broadband anti-reflection coating optimized for 3–5 µm (average reflectance <0.5% per surface)
• Precision-polished surfaces with RMS roughness <5 Å, minimizing scatter losses in low-signal applications such as gas-phase absorption spectroscopy
• Standardized mechanical dimensions compatible with industry-standard SM1 (1.035″-40) and SM2 (2.035″-40) lens mount threads—enabling rapid integration into modular optomechanical breadboards and OEM laser housings
• Batch-certified material homogeneity per MIL-O-13830A; individual lenses supplied with traceable metrology data including measured EFL, centration error (<3 arcmin), and surface irregularity

Sample Compatibility & Compliance

The Meg1025 lens is suitable for use with continuous-wave (CW) and pulsed mid-IR sources including QCLs, CO lasers, and synchrotron-based infrared beamlines. Its CaF₂ composition provides immunity to moisture-induced degradation—unlike ZnSe or Ge—making it ideal for field-deployable environmental monitoring instruments. All lenses conform to ISO 10110-1 (optical component drawing standards), ISO 10110-7 (surface imperfection limits), and ASTM F2739 (test methods for IR transmittance of optical materials). Uncoated versions meet USP requirements for non-leachable particulate generation in cleanroom-compatible optical assemblies.

Software & Data Management

While the Meg1025 is a passive optical component, its geometric and material parameters are fully integrated into standard optical design software libraries—including Zemax OpticStudio (v23+), CODE V (v12.2+), and FRED—via native .ZMX and .SEQ import templates. Each shipment includes a digital calibration certificate (PDF + CSV) containing measured focal length deviation, transmitted wavefront error (TWE) at 4.26 µm (HeNe reference), and coating spectral reflectance curves (200 nm–12 µm). Traceability supports GLP-compliant documentation workflows and FDA 21 CFR Part 11–aligned audit trails when paired with laboratory information management systems (LIMS).

Applications

• Beam collimation and focusing in 3–5 µm QCL-based standoff chemical detection systems
• Objective and relay optics in Fourier-transform infrared (FTIR) microspectrometers
• Input/output coupling optics for cryogenically cooled MCT detector modules
• Reference elements in radiometric calibration chains compliant with NIST-traceable protocols
• UV-excited luminescence collection optics where CaF₂’s deep-UV transparency (down to 180 nm) and absence of auto-fluorescence provide signal fidelity unmatched by fused silica

FAQ

Is the IR1 coating durable enough for cleaning with acetone or isopropanol?
Yes—the IR1 multilayer dielectric stack (Ta₂O₅/SiO₂ alternating layers) is rated for Class 1000 cleanroom handling and withstands repeated solvent wiping using spectroscopic-grade IPA under controlled humidity (<30% RH).
Can the Meg1025 be used in vacuum environments?
Yes—CaF₂ exhibits negligible outgassing (total mass loss <0.05% per ASTM E595) and no volatile binders or adhesives are used in fabrication; it is qualified for UHV applications up to 10⁻⁹ Torr.
What is the maximum permissible power density for CW 4.6 µm laser operation?
At 4.6 µm, the damage threshold exceeds 1.2 GW/cm² for 10-ns pulses (10 Hz, 1064 nm equivalent scaling); for CW operation, thermal lensing remains negligible below 5 kW/cm² on uncoated surfaces.
Are custom focal lengths or diameters available?
Yes—MiXran offers OEM customization including non-standard EFLs (±0.5% tolerance), aspheric corrections, and kinematic mounting interfaces (e.g., flexure-mounted lens cells); lead time: 6–8 weeks.
Does the lens include certification for ISO/IEC 17025 accredited calibration?
Individual units can be supplied with third-party calibration reports from CNAS-accredited labs (e.g., Beijing Institute of Metrology), covering focal length, radius of curvature, and transmission uniformity—available upon request at additional cost.