• Achromatic Design for Nearly Gaussian Collimation Over Mirror's Reflection Band
• Protected Silver (450 nm - 20 µm) Coating Offers High Reflection
• Great for Coupling Polychromatic Light into Multimode Fiber
• Ø11 mm Aperture
• Non-Magnetic Stainless Steel Housing

Thorlabs' metallic-coated Reflective Collimator is based on a 90° off-axis parabolic mirror. Mirrors, unlike lenses, have a focal length that remains constant over a broad wavelength range. Due to this intrinsic property, a parabolic mirror collimator does not need to be adjusted to accommodate various wavelengths of light, making them ideal for use with polychromatic light.

By using the Protected Silver (450 nm - 20 µm)-coated mirror, this collimator offers excellent usability over its design wavelength range. Common applications include systems that utilize multiple wavelengths that need to be collimated, collimation/coupling in the IR, and coupling polychromatic light into large core multimode fiber.

Note that light cannot be well collimated from a multimode fiber. However, if you are attempting to collimate light from multimode fiber, the Numerical Aperture (NA) of the fiber should be <0.36 (RC04), <0.167 (RC08), or <0.216 (RC12) to avoid the collimator housing from clipping light emitted from the fiber tip. As the core size of the fiber gets larger, the resulting minimum divergence angle will increase as well, thus yielding an output that cannot be well-collimated.

• Mirror Surface Quality: 40 – 20 Scratch-Dig
• Surface Roughness: <100 A RMS
• Mirror Coating: Protected Silver (450 nm - 20 µm)
• Reflectance: >97.5% (450 - 2 µm), >96% (2 - 20 µm)
• Mirror NA: 0.167
• Effective Focal Length: 33 mm
• Parent Focal Length: 16.5 mm
• Full Angle Beam Divergence: 0.02°
• Fiber Connector: FC/PC
• Clear Aperture: Ø11 mm
• Beam Diameter: 8.5 mm