Description
A quartz light guide rod carries light along its length by total internal reflection, with light entering and exiting through finished end faces. This page covers plain, ungrooved light guide rods. For rods with a machined alignment groove for fiber or component positioning, see Grooved Light Guide Rods.
The key purchasing parameters are rod diameter, finished length, end-face quality and the geometry of each end. Unlike general quartz rod stock, the optical end condition is part of the functional specification.
Dimensions & Tolerance
| Parameter | Specification |
|---|---|
| Diameter | 1–100 mm; D2–D10 mm, D10–D20 mm and D30–D40 mm are common stocked diameter groups, with custom diameters available to D100 mm |
| Length | 10–200 mm stocked increments; custom lengths available to the required finished dimension |
| Diameter Tolerance | ±0.05–0.1 mm |
| Length Tolerance | ±0.1–0.2 mm |
| Surface Roughness, Polished Ends | Ra 0.05–0.2 µm |
Optical Path
Axial Light Transmission — Light enters through a polished end face and is guided along the rod axis by total internal reflection at the quartz-to-air boundary.
Straight Rod — Used for point-to-point light transmission where input and output remain on the same axis.
Angled End Geometry — An end face can be produced at an angle, including 45° configurations, when the optical path needs to be redirected at the rod end.
End Finish
| Finish | Detail |
|---|---|
| Optically Polished | Both ends polished flat and parallel for high-transmission coupling |
| Surface Quality | Scratch-dig 60/40 standard option; 30/20 or 20/10 available when specified |
| Blackened | End treatment used where suppression of unwanted light at a selected end is required |
| Diffused | Diffuse end finish for controlled scattering rather than direct polished transmission |
| Angled | End angle specified individually; the two ends can use different geometries |
Chamfer
A chamfer at the polished end reduces edge chipping and helps control stray light scatter at the rim. Chamfer size is specified with the end-face requirement so it does not interfere with the clear optical aperture.
Material
| Property | Specification |
|---|---|
| Standard Material | High-purity fused quartz, SiO₂ ≥99.998% |
| Optical Grade Option | JGS2 optical grade for higher-clarity requirements |
| Profile | Plain round rod; ungrooved light-guide geometry |
What to Specify
| Parameter | Quotation Input |
|---|---|
| Diameter | Finished diameter and tolerance |
| Length | Finished length and tolerance |
| Input End | Flat / polished / angled / diffused / blackened |
| Output End | Flat / polished / angled / diffused / blackened |
| Surface Quality | 60/40, 30/20, 20/10 or required optical specification |
| End Roughness | Ra requirement within the polished-end range |
| Chamfer | Chamfer width / angle and clear aperture requirement |
| Quantity | Prototype or production quantity |
FAQ
What diameter tolerance can you hold on a light guide rod?
±0.05 mm is commonly held on precision-grade rod. Tighter requirements should be checked against the finished diameter, length and end-face specification together.
Can both ends have different finishes — one flat, one angled?
Yes. End geometry is specified independently for each end, so one end can be a straight polished face and the opposite end can use an angled face.
Do you offer a version with an alignment groove?
Yes. See Grooved Light Guide Rods for quartz light guide rod with a machined groove for fiber or component positioning.