art photonics FOCO-S-3/5-F5 Mid-Infrared Fiber Collimator with ZnSe Lens, 3–5 µm, 5 mm Focal Length

Overview

The art photonics FOCO-S-3/5-F5 is a precision-engineered mid-infrared (MIR) fiber collimator designed for stable beam shaping and spatial coupling in spectroscopic, sensing, and laser delivery systems operating within the 3–5 µm atmospheric transmission window. Built around a monolithic zinc selenide (ZnSe) aspheric lens with a nominal focal length of 5 mm, this collimator enables diffraction-limited collimation of radiation emitted from single-mode or low-numerical-aperture multimode MIR fibers—particularly those based on chalcogenide (e.g., As₂S₃, Ge-As-Se) or fluoride glass materials. Its mechanical architecture integrates a kinematic, stress-free lens mount with a stainless steel housing featuring standard SM1 (1.035″-40) external threading, ensuring compatibility with industry-standard optomechanical stages, translation mounts, and vacuum-compatible optical tables. The collimator’s optical design minimizes spherical and chromatic aberration across its specified spectral band, supporting high-fidelity beam propagation essential for Fourier-transform infrared (FTIR) spectroscopy, quantum cascade laser (QCL) beam conditioning, and gas-phase molecular absorption measurements.

Key Features

• Zinc selenide (ZnSe) lens optimized for high transmission (>70% per surface, uncoated; >95% per surface with broadband AR coating option) across 3–5 µm
• Fixed 5 mm focal length delivering compact collimated output with typical beam divergence < 5 mrad (dependent on input fiber NA and core diameter)
• Hermetically sealed, non-adjustable housing with integrated fiber ferrule alignment—no post-installation tuning required
• Compatible with Ø2.5 mm or Ø3.2 mm ferrules (FC/PC or SMA-905 interface; custom termination available upon request)
• Compliant with ISO 10110-5 surface quality specifications (scratch-dig 60–40), surface flatness λ/4 @ 633 nm (test wavelength), and wavefront error < λ/8 RMS over clear aperture
• RoHS-compliant construction with passivated stainless steel body and gold-plated internal baffles to suppress stray light

Sample Compatibility & Compliance

The FOCO-S-3/5-F5 is validated for use with silica-clad or polymer-jacketed chalcogenide fibers (e.g., art photonics’ IRflex series), as well as bare-core fluoride fibers rated for continuous-wave operation up to 2 W average power in the MIR range. It supports both free-space coupling into FTIR interferometers and integration into OEM gas analyzers requiring repeatable alignment under thermal cycling (operating temperature range: –10 °C to +60 °C). All units undergo individual collimation verification using a calibrated MIR pyroelectric camera and HeNe reference alignment, with test data traceable to PTB (Physikalisch-Technische Bundesanstalt) standards. The device conforms to IEC 61340-5-1 for electrostatic discharge (ESD) safety during handling and meets CE marking requirements for optical radiation safety (EN 60825-1:2014 Class 1).

Software & Data Management

While the FOCO-S-3/5-F5 is a passive optical component requiring no firmware or driver software, its performance is fully documented in art photonics’ optical component database (accessible via registered customer portal). Each unit ships with a calibration certificate listing measured collimation efficiency (defined as ratio of far-field intensity at beam center to total integrated power), measured wavefront error (via Zygo Verifire Interferometer), and spectral transmittance curve (measured on Bruker Vertex 80v FTIR). For system-level validation, art photonics provides MATLAB- and Python-compatible spectral data files (.csv, .mat) and mechanical CAD models (STEP, IGES) compliant with ASME Y14.5 GD&T standards—enabling direct import into optical design suites such as Zemax OpticStudio or CODE V.

Applications

• Beam collimation and focusing in tunable QCL-based trace gas detection platforms (e.g., NH₃, CO, CH₄, NO)
• Input/output coupling for MIR photonic integrated circuits (PICs) and on-chip spectrometers
• Reference path conditioning in dual-beam FTIR systems with liquid-nitrogen-cooled MCT detectors
• Free-space optical interconnects in industrial process monitoring systems operating under harsh ambient conditions
• Calibration-grade components in national metrology institute (NMI) setups for MIR radiometry and radiance transfer standards

FAQ

Is anti-reflection coating included by default?
No—the standard FOCO-S-3/5-F5 ships with uncoated ZnSe optics. Broadband AR coatings (3–5 µm, R < 0.5% per surface) are available as a factory option (specify suffix “-AR” at order entry).
Can this collimator be used with pulsed MIR sources?
Yes—provided peak power density remains below 100 MW/cm² (for nanosecond pulses) or 1 GW/cm² (for femtosecond pulses), consistent with ZnSe damage threshold specifications per ISO 21254.
What fiber types are mechanically and optically compatible?
Recommended: art photonics IRflex-2.5, Le Verre Fluor FLUOROFLEX-MIR, or Thorlabs FG200LCC (with ZnSe capillary sleeve). Avoid fibers with jacket OD > 3.5 mm without custom housing modification.
Is vacuum compatibility supported?
Yes—the housing uses metal-to-metal seals and contains no outgassing polymers; it is rated for UHV use (<10⁻⁹ mbar) when baked to 120 °C per ASTM E595 testing.
Do you provide custom focal lengths or lens materials?
Yes—custom configurations including GaAs (8–12 µm), AMTIR-1 (3–12 µm), or CaF₂ (0.2–10 µm) lenses, as well as focal lengths from 2 mm to 50 mm, are available under art photonics’ OEM engineering service (lead time: 8–12 weeks).