ART Photonics FORO-L-3/5-F10 Mid-Infrared Fiber Coupling Objective Lens

Overview

The ART Photonics FORO-L-3/5-F10 is a precision-engineered mid-infrared (MIR) coupling objective lens designed specifically for efficient light coupling between free-space optical systems and infrared-transmitting fiber cables—particularly sulfur-based chalcogenide (CIR) fibers operating in the 3–5 µm spectral band. Unlike broadband visible or NIR optics, MIR objectives require specialized materials and anti-reflection (AR) coatings to minimize absorption losses and maximize throughput in this thermally critical region. Constructed from high-purity zinc selenide (ZnSe), the FORO-L-3/5-F10 features a plano-convex configuration with an AR coating optimized for peak transmission across 3–5 µm. Its fixed focal length of 10 mm and numerical aperture of 0.35 enable robust collimation or re-focusing of divergent MIR beams emerging from fiber terminations, supporting quantitative spectroscopic measurements where signal fidelity and spatial stability are essential.

Key Features

• Zinc selenide (ZnSe) optical element with broadband AR coating optimized for 3–5 µm transmission (>95% per surface)
• Re-focusable mechanical design allowing precise axial adjustment for optimal beam coupling efficiency
• M24×1 external thread for secure integration into standard optical mounts and compatibility with Thorlabs SM1, RMS, and S-mount adapters (optional)
• Non-magnetic, black anodized aluminum housing ensuring thermal stability and EMI resilience in laboratory and industrial environments
• Direct interface with SMA- or FC/PC-terminated infrared fiber cables via integrated connector alignment sleeve
• Compact form factor (Ø25 mm × ~37 mm) enabling integration into space-constrained FTIR, gas sensing, and process monitoring setups

Sample Compatibility & Compliance

The FORO-L-3/5-F10 is validated for use with ART Photonics’ CIR-series chalcogenide fibers (e.g., CIR-350, CIR-500), which exhibit low attenuation and high power handling in the 1.5–6 µm range. It is also compatible with other ZnSe-coupled MIR fiber systems meeting ISO 11146 beam parameter standards. While not a regulated medical device, its material composition and surface finish comply with ISO 10110-7 (optical component cleanliness) and EU RoHS Directive 2011/65/EU. The lens is suitable for applications requiring GLP-compliant documentation, including environmental gas analysis (per EPA Method 320), industrial combustion diagnostics, and semiconductor process control under ASTM E1421–22 guidelines.

Software & Data Management

As a passive optical component, the FORO-L-3/5-F10 does not incorporate embedded firmware or digital interfaces. However, it is fully interoperable with industry-standard spectroscopic data acquisition platforms—including Ocean Insight’s OceanView, Hamamatsu’s LightMaster, and Thermo Fisher’s OMNIC—when deployed within fiber-coupled FTIR, QCL, or tunable diode laser absorption spectroscopy (TDLAS) systems. Its mechanical repeatability (<±2 µm axial positioning tolerance) ensures consistent beam alignment across measurement sessions, supporting audit-ready calibration logs and traceable intensity normalization workflows compliant with FDA 21 CFR Part 11 requirements when used in regulated QC/QA environments.

Applications

• Gas-phase molecular spectroscopy targeting fundamental vibrational bands of CO, CO₂, CH₄, NOₓ, and volatile organic compounds (VOCs)
• In-situ process monitoring in petrochemical refineries and semiconductor etch chambers using extractive or open-path MIR fiber probes
• Medical breath analysis research requiring high-fidelity coupling of quantum cascade laser (QCL) sources to hollow-core or solid-core MIR fibers
• Remote thermal imaging systems integrating MIR fiber bundles with cooled MCT or InSb detectors
• Calibration reference optics in NIST-traceable MIR radiometry setups operating at ambient or elevated temperatures (up to 80 °C)

FAQ

Is the FORO-L-3/5-F10 compatible with both FC/PC and SMA fiber connectors?

Yes—the lens housing incorporates a universal alignment sleeve accepting both FC/PC and SMA-terminated chalcogenide fibers without adapter modification.
Can this objective be used with 8–12 µm halide glass fibers?

No—this specific model (FORO-L-3/5-F10) is AR-coated exclusively for 3–5 µm. For 8–12 µm operation, specify FORO-L-8/12-F10.
What is the maximum input beam diameter supported?

The effective clear aperture is Ø13.5 mm; incident beams exceeding this diameter will experience vignetting and reduced coupling efficiency.
Does ART Photonics provide mounting fixtures or kinematic mounts for this lens?

Standard M24×1 threading allows direct mounting to commercial kinematic platforms (e.g., Thorlabs KM100, Newport UMB3); custom machined adapters are available upon request.
Is ZnSe susceptible to moisture or chemical degradation in field deployments?

ZnSe is hygroscopic only under prolonged condensation exposure; proper housing sealing and desiccant integration in fiber probe assemblies mitigate risk per IEC 60068-2-30 humidity testing protocols.