Topic 5 min read

A new approach to circular dichroism

Latest updated: October 1, 2019

A combination of the most up-to-date double grating monochromator with the MOS-500’s chromatic light source results in the the most advanced, versatile instrument possible for circular dichroism spectroscopy.

As a result of a cutting-edge design, the MOS-500 delivers the highest levels of precision for any instrument on the market, but also reduces running costs significantly because nitrogen is rarely needed during experiments (meaning users can save up to 5,000€ per year).  This optimal design also reduces wear and tear on the instrument, consequently increasing its lifespan.

Conventional CD spectrometers based on double prism monochromators use prisms to polarize light. Prisms provide good wavelength resolution in UV region, but in the visible and IR region however, wavelength precision can be reduced by a factor of 20.  MOS-500 exploits double holographic reflective gratings to offer a constant wavelength accuracy over the full wavelength range.

The use of a patented tunable chromatic light source is also described in this article. Using a combination of tunable lenses, only the selected wavelength is correctly focused on the entry slit of the monochromator. This results in a very significant reduction of stray light.  It also prevents damage to the optics due to the reduction of UV entering the monochromator when working at high wavelength. The optic lifetime is thus longer and operating costs are reduced when compared to classical achromatic light sources.

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Circular Dichroism MOS-500 Grating monochromator stray light