Considerations for Sphere Selection
Several factors need to be considered when determining the integrating sphere size that is appropriate for your application. Three of the most important factors are:

Diameter/Source Size
The sphere diameter should be at least 1 1/2 times the largest dimensions of any device mounted within the sphere.

Surface to Port Area
Proper integrating within an integrating sphere is insured when not more than 5% of the sphere wall surface area is taken up by ports. If port requirements exceed that percentage, a larger sphere should be considered. Port area and sphere surface area can be determined by the following simple formulas:

Port Area = r²
Sphere Surface Area = D²
r = port area, D = sphere diameter

Integrating Sphere Coatings
In order to deliver reliable integration and low throughput loss, the coating of the integrating sphere must be a very efficient diffuse reflector. The reflectance must be high in order to minimize absorption loss due to multiple reflections, but it must not reflect light in a specular sense.

Coatings used on Labsphere integrating spheres offer reflectance efficiencies between 95 and 99%. When a perfect diffuse reflector is illuminated with uniform intensity, it behaves as a perfect diffuse source - a Lambertian source. Labsphere's Spectralon, Spectraflect, Duraflect and Infragold coatings provide these excellent Lambertian properties.

Sphere Selection Chart
The following chart is provided as a comparison index for the integrating spheres described in this section. We hope it will assist you in quickly locating a sphere for your application. View Sphere Selection Chart