Spectrophotometer Design

The UV-visible-NIR spectrophotometer, such as CRAIC Technologies Lightblades™, measure the intensity of electromagnetic energy wavelength by wavelength. 

How the Spectrophotometer Works

 

UV-visible-NIR spectrophotometer

The spectrophotometer is an optical instrument for measuring the intensity of light relative to wavelength. Electromagnetic energy, collected from the sample, enters the device through the aperture (yellow line) and is separated into its component wavelengths by a holographic grating. The separated light is then focused onto a CCD array detector where the intensity of each wavelength is then measured by a pixel of the array. The CCD is then read-off to a computer and the result is a spectrum which displays the intensity of each wavelength of light.

An example would be a spectral measurement of the visible range which we perceive of as color.  White light would enter the monochromator and be separated into a rainbow of each color.  This rainbow, with blue light on one end and red on the other, would be focused on to the CCD.  Each pixel of the CCD would then measure the intensity of a color.  The results would be a spectrum such as the one shown below.  As shown, the blue pixels emit blue light, the green pixels emit in the green portion of the spectrum and the red pixels emit red light.

Spectra of red, green and blue pixels of an OLED display

In a microspectrophotometer, such as those made by CRAIC Technologies, the Lightblades™ spectrophotometer is integrated with a specially designed microscope. This integration allows for spectroscopy of microscopic sample areas.