UM Series Integrating Spheres

Gigahertz-Optik’s UM*) series integrating spheres and accessories (sphere components) offer one of the most extensive integrating sphere and IS integrating sphere system programs available. The modular design concept allows integrating spheres to be set-up according to the customer’s own application specifications and budget requirements. Each integrating sphere is built to order from stock standard components using an efficient cost effective production process. Custom modifications of standard components, custom design components and complete system set-ups are offered.
*) the Ulbrichtsche Kugel (Integrating Sphere) is named for the designing engineer Richard Ulbricht (1849 to 1923). M stands for Modular concept

Principal Integrating Sphere Set-up:

Gigahertz-Optik manufactures UMB integrating spheres in many different diameters. The base spheres which form the foundation of all integrating spheres and systems are built with two identical hemispheres. The hemispheres are configured with sphere components that are assembled onto the sphere (Pictures 1 & 2). These components include:

• UMSS: Sphere Stands
• UMPF: Port Frames
• UMDP: Detector Ports
• UMPB: Port Baffles

Once the base sphere is configured with ports and port frames, port adapters and other sphere accessories like light sources, light detectors and sample holders (Picture 3) are mounted onto the appropriate type port frame. Light meters, light analyzers and reference detectors that are part of the integrating sphere system are calibrated by our calibration laboratory for light measurement units.

Principal Application Set-up of Integrating Spheres:

ISD Integrating Sphere Detectors:

Light measurement is the primary integrating sphere application. Light emitted in different directions or wide dispersion angle is internally integrated within the sphere for detection. A means of attenuation to reduce the light intensity reaching the light detector to avoid over ranging is often implemented.

Typical integrating sphere designs for total flux measurement of light sources include:

1. Integrating sphere for all directional emitting sources set-up with a lamp holder and post for positioning and operation of the test lamp in the center of the sphere. A light detector is mounted onto the sphere that is baffled to block direct irradiation by the test source and a diffuser window with wide field-of-view is installed for more complete integration of the total sphere surface (Picture 4). A light meter or light analyzer completes the system.

2. Integrating sphere for spot (beam emitting) lamps, fiber light guide output and lasers the sphere is typically set-up with an application port enabling operation of the source outside the sphere. A light detector is mounted onto the sphere that is baffled to block direct irradiation by the test source and a diffuser window with wide field-of-view is installed for more complete integration of the total sphere surface (Picture 5). A light meter or light analyzer completes the system.

3. Integrating sphere for spot lamps and LEDs with a hemispherical emitting characteristic is set-up with an application port enabling operation of the source outside the sphere. A light detector is mounted onto the sphere that is baffled to block direct irradiation by the test source and a diffuser window with wide field-of-view is installed for more complete integration of the total sphere surface (Picture 6). A light meter or light analyzer completes the system.

ISS Integrating Sphere Sources:

The second important application for integrating spheres is the sphere based light source offering a large size uniform light output with hemispherical emittance characteristic.

The typical design set-ups are:

1. Integrating sphere source with internally mounted light source(s) offers the highest light output in relation to the source flux since most of the light is contained within the sphere. Intensity control is achieved in steps by switching lamps on and off (Picture 7). There is no other way to control intensity.

2. Integrating sphere source with externally mounted light source(s) enable variable light output through the use of variable apertures or hole pattern attenuators. Halogen tungsten or arc lamp intensity cannot be controlled by varying electrical power input without influencing color temperature (emission spectrum) and flux stability (Picture 8).

3. Integrating sphere sources employing LEDs offer intensity control in steps (on-off) and variable output intensities through electrical power control (Picture 9).

ISMP Integrating Spheres for Optical Properties of Material s Testing:

The third main application of integrating spheres is in reflectance, transmittance, absorbance, fluorescence or OPM optical properties of material measurements.

Typical design set-ups include:

1. Integrating sphere with sample port and collimated light source for sample irradiation through the sphere. Measurement of total reflectance or diffuse reflectance with open port for regular reflected light (Picture 10)

2. Integrating sphere with sample port and collimated light source for sample irradiation opposite to the sample port. Measurement of total transmittance or diffuse transmittance with open port for regular transmitted light (Picture 11)

3. Integrating sphere with sample holder mounted in the sphere center. Through port illumination of the test sample with collimated light source (or laser). Measurement of absorbance by calculating the ratio of signal with and without test sample or measurement of fluorescence or photoluminescence of the stimulated test sample (Picture 12)

Typical set-up designs with diffuse light sources are:

1. Integrating sphere with sample holder for the positioning of the test source in the sphere centre. Irradiation of the test sample with diffuse light. Measurement of absorbance by the ratio of signal with and without test sample (Picture 13)