• Versatile Fiber to Free-beam Lens. Couples easily to any SMA 905 connector or 1/4" ferrule
  
• Adjustable from Near 0° to ~45°. Focuses for collimation or de-focuses to expand the field of view

74-Series Collimating Lens Fixtures
The 74-series Collimating Lens Fixture is the common fiber optic-coupled lens fixture used throughout our extensive line of sampling accessories. Accessories include lenses of fused silica (74-UV), BK-7 glass (74-VIS) or a doublet of BaF10 and FD10 glass (74-ACR). 

Made of stainless steel with a black oxide finish, 74-series lenses have an inner barrel threaded for SMA 905 connectors (1/4" OD FC barrels are available). The inner barrel slides relative to the lens fixture to adjust the focus; a setscrew secures it. Adjustment from converging to diverging FOV (~45°) is possible. These are 74-series Lens options:

74-UV Collimating Lens (200 nm-2 µm). The 74-UV has an f/2 fused silica lens for the UV-VIS-NIR. When focused for collimation, beam divergence is 2° or less, depending on fiber diameter. Single-lens systems have the disadvantage of chromatic aberration, due to the dispersion or variation in refractive index with wavelength. The 74-UV can be adjusted to optimize performance for UV or VIS-NIR applications. It comes with accessories such as the CUV-UV, CUV-UV-10, CUV-FL-DA, CUV-ALL-UV, ISS-2, FHS-UV and DT-1000. The 74-UV is $159.

Also available is the 74-UV-HT, which has a high-temperature bond to withstand temperatures up ~150 °C (the standard 74-UV is rated to 70 °C).

74-VIS Collimating Lens (350 nm-2 µm). The 74-VIS has a BK-7 lens suitable for the VIS-NIR. It comes with the LS-1 and LS-1-CAL Light Sources. The 74-VIS is $159.

74-ACR Collimating Lens (350 nm-2 µm). The 74-ACR has two optical elements cemented together to form an achromatic doublet, optimized to correct for spherical and chromatic aberrations. The 74-ACR is $199.

84-Series Collimating Lens Fixtures
The 84-series Lens Fixture is designed for coupling larger optics to fibers. The 1-inch diameter lens is held in an outer assembly with a retaining ring, facilitating replacement. The fiber is coupled to the assembly with an inner 0.7" threaded barrel. The barrel positions the fiber ~100 mm from the lens surface and is turned to achieve a fine focus. The 84-UV-25 is an 84-series lens with a fused silica 25.4-mm diameter, 100-mm focal length lens, especially suitable for open-air work from 200 nm-2 µm. The 84-UV-25 is $499.

Collimating Lens Fixtures -- Accessories
74-series Collimating Lens Fixtures are available with several accessories that facilitate the mounting of lenses and fibers:

74-90-UV Right Angle Collimating Lens. The 74-90-UV is a 3/8-24 threaded black anodized aluminum assembly for mounting lenses at right angles. It has a flat front surface Al-coated mirror located under its cap that reflects light from the collimating lens to 90°. Two 3/8-24 threaded ports accommodate 74-series lenses and accessories. The 74-90-UV is $99. For more on the 74-90-UV, click here.

74-ACH Adjustable Collimating Lens Holder. The 74-ACH consists of an anodized aluminum base and adjustable bars; each bar has several threaded holes for collimating lenses. The bars can be set far enough apart to accept samples up to ~100 mm thick, making the 74-ACH perfect for transmission measurements of large or thick samples. The 74-ACH is $299. For more on the 74-ACH, click here.

74-OPM Optical Post Mount. The 74-OPM is a 3/8-24 threaded black anodized aluminum assembly, 1-1/2" in diameter with an 8-32 x 1/2" bore for mounting collimating lenses onto breadboard laboratory tables, rail carriers and other bench plates. The 74-OPM is $99. For more on the 74-OPM, click here.

Collimating Lens Fixtures -- Technical Tips

• The divergence (a) of a beam focused using a single lens is tan(a) = d/f where f is the focal length of the lens and d is the aperture or fiber diameter.
  
• The optical fibers Ocean Optics specifies for use with its spectrometers and light sources have FOV of ~25° -- an acceptance angle that may not be optimum for some experiments. Collimating lenses are adjustable, allowing the user to establish FOV angles from near- collimation (~ 0°) to ~45°.
  
• Be careful when adjusting collimating lenses, as inaccurate focusing of the lens can result in a de facto change of the sample path length.

Collimating Lens Fixtures -- Specifications

Collimating Lens Fixtures -- Ordering Information

Contact an Ocean Optics Applications Scientist

Collimating Lens Specifications

Collimating Lens Ordering Information

Adjusting Collimating Lenses

Right-angle Reflector for Collimating Lenses

Adjustable Collimating Lens Holder

Optical Post Mounts for Collimating Lenses

Additional Sampling Accessories