The DSR-λ Multiple Wavelength Automatic Refractometer from Schmidt+Haensch is the world’s first instrument to offer multiple wavelength measurement of refractive index at the digital, automatic level.

Refractometers measure the critical angle of total reflection and calculate the refractive index from this value. The R.I. of a substance depends on the wavelength of light and usually increases at smaller wavelengths. For a better characterization of this behavior, Ernst Abbe introduced in the late 19th century what became known as the Abbe Number; it’s an arithmetically dimensionless value calculated from measured refractive indices at 486.1, 589.3, and 656.3nm.

In modern times this formula isn’t used as frequently, since the development of high-accurate refractometers made it possible to measure R.I. differences at a resolution of 0.00001. However, information regarding R.I. values at other wavelengths is lost. By accurately measuring samples at 7 separate wavelengths, the DSR-λ effectively takes R.I. measurements to the “fingerprinting” level. Many chemically different solutions may exhibit similar R.I. values at the traditional 589.3nm (sodium) wavelength. However, when a spectral-analysis takes place at the R.I. level, the key differences can be obtained from otherwise similar samples.

Electronic Peltier temperature control (+18 to +30°C) comes standard on the DSR-λ to deliver the highest level of precision for R.I. testing. With accuracy of ±0.01°C, a temperature is easily set and the refractometer quickly heats or cools to the target level before conducting measurements. The DSR-λ also features a long-lasting LED light source (100,000 hours), linear high-resolution CCD sensor, menu-driven backlit LCD displays, 4 user profiles, password protection, printer and data ports, & optional USB ports.

The included software package and RS-232C cable make it very easy to connect the DSR-λ to computers for collection of measurement data or for remote operation with full command of all functions. As new software versions are released, the instruments can also receive flash updates.