Integrating spheres are multifaceted optical instruments designed to measure high-precision reflectance and scattered transmittance of virtually any surface. Scientists designed these units to achieve a homogenous distribution of optical radiation at the sphere’s inner surface. A diffuse white covering typically covers the interior of the spheres to ensure a uniform scattering effect. Specialists use them with a light source and a detector to measure optical power. Differences in the make-up of the inside coating of the spheres result in different radiances produced by the spheres.
The integrating spheres, along with high-quality light detectors, are crucial when measuring optical power, which is necessary for a number of specific applications. Measurements, usually as wavelengths, are performed spectrally. Applications range from surface studies of solids to photometric studies of colloidal, turbid, translucent and transparent samples. Several applications are often used in today’s world. Listed below are some of the most common applications making use of integrating-sphere systems.
The Characterization of Solar Cells
Scientists and manufacturers use UV/Vis spectroscopy to measure the transmission loss of silicon photocells.
Analysis of Security Ink
The spectra from paper money can show the variable reflectance in the visible and near-IR measurements, resulting in a full representation of each ink measured across the spectral range.
The Distinction Between Specular and Diffuse Reflectance
Scientists can analyze samples having different gloss characteristics or varying surface polishing when in the specular and diffuse reflectance mode.
Color Analysis
Scientists use integrating spheres and detectors for accurate color measurements, enabling precise color matching. This is especially important within industries such as textiles and paint production.
Determination of Food Constituents
The integrating sphere system allows for excellent qualitative and quantitative measures in this area. After calibration, scientists can accurately determine the content of fat, protein and water in a sample.
Determinations of UV Resistance
Scientists use the integrating sphere system to test pharmaceutical containers, solar-protective clothing and automotive paints for their resistance to UV waves.
IR-total Hemispherical Reflectance
This measurement is crucial when applied to the radiant heat transfer analysis of thermal control coatings and foils used in spacecraft design.
Measuring Output of Light Power of Lasers and LEDs
The integrating sphere system has played a large part in the development of these items. Precise measurements of light waves determine the power and color characteristics available. Lasers are fundamental for fiber optics, range finders and communication systems, to name a few. Traffic lights, automotive lighting and home light bulbs are a few of the items that contain LEDs.
Medical Applications
Dermatologists use UV radiation to treat several skin conditions such as Vitiligo and Psoriasis. They have created specifications for the treatments through the use integrating sphere systems.
Relationship Between Plants, Seeds and Soil, and Optical Radiation
The study and control of biochemical factors require accurate measurement technology. Absorbing optical radiation at particular wavelengths is essential for growth.
Ultraviolet Radiation Effects
The weakening of the ozone layer has necessitated the ability to measure the UV radiation precisely. UV rays are harmful to human skin and eyes. On the other hand, since these rays are hazardous to living organisms, they are an efficient method for killing bacteria, mold, germs and fungus. Consequently, they are used as an economical treatment technique for drinking water and wastewater.
Telecommunications
Measurements of the power output of laser diodes and fibers are made daily in this field using the information generated by the integrated sphere system.
These are just a few of the ways in which integrating spheres increase the accuracy in the measurement of light waves, including IR, Vis and UV rays. These systems allow for the precise calibrations needed in many applications used today.