Fiber Bundle Focusing Assemblies include a focusing lens, manual shutter, and fiber bundle holder contained into a single enclosure. These assemblies have a 1.5 inch male flange for easy coupling to Oriel Research Lamp Housings and have a 1/4-20 threaded hole on the bottom of the housing for mounting with an Optical Rod. A thumbscrew allows positional adjustment of a fiber bundle of light guide within 1 mm. These assemblies are designed to enclose light guides and fiber bundles with standard Oriel 11 mm ferrule termination. Three different Fiber Bundle Focusing Lens Assemblies are offered:

• 77799 : Contains f/0.85 Aspheric Pyrex lens, should be used with glass Fiber Bundles and Liquid Light Guides
• 77776 : Contains f/2.2 Fused Silica lens, should be used with fused silica fiber bundles and single core fibers
• 77800 : Contains f/2 Plano Convex lens, should be used with fused silica fiber bundles and liquid light guides

Aspheric lens such as those used in the 77776 and 77799 are designed for less aberration than plano convex lenses, therefore providing better spot size uniformity. The typical spot size diameter for each light guide is:

• 77799 : 4 mm
• 77776 : 800 µm
• 77800 : 4 mm

These spot sizes were measured by re-imaging the arc with each Focusing Assembly formed by a 75 W Xe Arc Lamp (arc size 0.25 mm x 0.25 mm) collimated by an f/1.5 condensing lens.

Secondary Focusing Lens Assemblies focus the collimated beam from a condensing lens assembly and create an image of the arc or filament one focal length away. They consist of a fused silica, plano convex lens and a flanged lens holder. The flanged lens holder can be purchased separately if the lens offered in each Focusing Lens Assembly is not suitable for the intended application. Each flanged lens holder has male and female flange compatible with the Oriel flanging system and a 1/4 - 20 threaded hole for mounting with an Optical Rod. Three Secondary Focusing Lens Assemblies are offered: model 6199: 1.5 inch flange, 6 inch Focal Length, F/4, 1.3 in. clear aperture; model 66110: 1.5 inch flange, 2 inch Focal Length composed of two lens elements, F/1, 1.3 in. clear aperture; model 6219: 2 inch flange, 6 inch Focal Length, F/3.3, 1.8 in. clear aperture. The flanged lens holders sold separately are: PN 6195: 1.5 inch flanged lens holder, which holds 1.5 inch optics; PN 6222: 2 inch flanged lens holder, which holds 2 inch optics; PN 6237: 3 inch flanged lens holder, which holds 3 inch optics.