integrating sphere


This device gathers electromagnetic radiation from a source that is entirely external to the optical device, and it is often used for flux measurement or optical attenuation in optical devices. An integrating sphere with numerous diffuse reflections is created by introducing radiation into the sphere and having it hit the reflecting walls several times. At the integrating sphere walls, the radiation is distributed in a very consistent manner as a result of the many reflections. In most cases, the resultant integrated radiation level is exactly proportional to the original radiation level, and it may be detected with relative ease by employing a detector.

Sphere diameters

Utility ports on the smaller diameter, less costly spheres must be smaller in order to maintain their very high throughput. In fact, depending on the light source, the throughput may be so great that filters or fibre optic cables are needed to keep the detector from being saturated. The port percentage of the smaller spheres, on the other hand, is very high. As a result, the measurement data produced by a tiny integrating sphere will be less precise than the measurement data generated by the same application utilizing a big integrating sphere

With lower throughput than smaller integrating spheres and greater optical attenuation, the bigger integrating sphere introduces more noise into the system, lowering the signal-to-noise ratio. These spheres are more flexible, but they are also more costly to produce because of their greater flexibility.

Sphere materials

The two aluminum hemispheres that make up the cost-effective barium sulphate coated GPS integrating spheres are assembled together. The hemispheres are connected together with screws via an anodized flange cover.

However, the hemispherical reflectance of barium sulphate begins to decline somewhat beyond 1850 nm, limiting the useful spectral range of the compound to 350-2400 nm. In the visible and near-infrared spectrums, this kind of sphere is suitable for the majority of radiation measuring applications.

Collimated laser beam power measurement

Obtaining a complete collimated laser beam power measurement that is independent of polarisation or beam alignment is a simple process. In order for the hot spot to be created at the 0-degree port, the beam must be allowed into the sphere from 180 degrees away via the 180-degree port.

When a detector is positioned at the 90-degree port, the baffle prevents direct radiation from the hot spot from reaching the detector, allowing for the measurement of spatially integrated beam power. The north port may be utilized as a light pick-off for the wavelength measurement since it is close to the sensor. Newport provides basic integrating sphere detectors calibrated as a single unit, as well as customized versions.

Fibre optic power output measurement

An integrating sphere is also a good choice for measuring the output of optical fibres, as previously stated. For this reason, and since the usual optical fibre output is slowly diverging, the initial reflection spot at the opposite side of the source is not particularly concentrated. If you need the best integrating sphere, LISUN has the best products for you.

As a result, most of the time, either the collimated beam configuration or the divergent beam configuration is sufficient. As a result of the higher numerical aperture (NA) of the fibre, the divergent beam arrangement is suggested in the case of lensed fibre. When utilizing a fibre collimator, it is suggested to use the collimated beam configuration as a starting point.

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