Spectral measurement

As its name says, a spectrometer is neither more nor less than a spectrum meter, or spectrum analyzer and in our case optical. It will determine which lambdas are present in the analyzed light. Is this a spectrophotometer? There is a lot of abuse of language but not really. A spectrophotometer is calibrated to also measure the “amount of light” in units relative to the perception of the human eye (photopic). If it is measured in radiometric units we then have a spectroradiometer. So these two calibrated spectrometers measure the amount of light for each wavelength.

 

A spectrometer measures the amount of light too, but in a very crude way in absolute terms, although very good in relative terms. For example, it will give a very good relative value between the amount of light at 532 nm and at 450 nm.

Many spectrometers come calibrated or have the option to be calibrated to normally give a radiometric response, but compact spectrometers with fiber input are what they are for: measuring spectra. If they give an indication of the power or amount of light in total or in each lambda, great, but let's not reach for the moon. Let's leave spectrophotometers and spectroradiometers for what they are, and with the high price they present.

 

In basic research or applied R&D laboratories, spectrometers are a fundamental and almost mandatory tool. In the industry they are increasingly implemented as OEM, especially for industrial process monitoring of all types and are present in pharmacy, agri-food, energy, automotive, water, mining, etc.,…

We are therefore talking about benchtop and laboratory spectrometers, and spectrometers in component format for OEM integration or spectral sensors dedicated to specific wavelengths.

 

There are spectrometers with the accessories, components or programming necessary to accurately undertake a specific application, for example:

- Raman spectrometer

- LIBS analyzer

- solar analyzer

- thin layer measurement system

- haze meter, transmission-transmittance, reflection-reflectance, absorption-absorbance

- fluorescence

 

Spectrometers basically break down (polychromatic) light into its monochromatic components, with the Czerny-Turner configuration being the most common today. How monochromatic each component is will be told by the resolution of the system.

The spectral range of sensitivity of the sensor at the end of the optical path will determine the useful measurement band. And the sensor material will determine the spectral range. Today, the two most common regions are:

- UV-VIS-NIR: ~200 - ~1100 nm – Si sensors (CMOS, CCD)

- SWIR: 900 – 1700 nm (SWIR-ext: 900 - ~2500 nm) – InGaAs sensors

But hey, finding the right sensor and diffraction element, any range is possible.

 

Chart of models: UV-VIS-NIR spectrometer:

Art.	Wavelength range	Resolution (FWHM)
	(nm)	typ. (nm)	max. (nm)
MAP-ARIS-0185-1000-20-x	185 − 1000	1	1.2
MAP-ARIS-0185-0550-20-x	185 − 550	0.4	0.6
MAP-ARIS-0185-0420-20-x	185 − 420	0.33	0.4
MAP-ARIS-0350-0840-20-x	350 − 840	0.6	0.7
MAP-ARIS-0510-1020-20-x	510 − 1020	0.8	1
MAP-ARIS-0300-1100-20-x	300 − 1100	1.1	1.4

 

Chart of models: NIR-SWIR spectrometer:

Art.	Wavelength range	Resolution (FWHM)
	(nm)	typ. (nm)	max. (nm)
MAP-SIENA-0940-1700-20	940 − 1700	8	10
MAP-SIENA-0800-1900-20	800 − 1900	12	14
MAP-SIENA-0900-2100-20	900 − 2100	13	16

 

The indicated resolution corresponds to a 20 um slit, others are available.

 

At PCL we are proud business partners – distributors of the German expert Avenir Photonics for Portugal and Spain. Our spectrometers are characterized by their small size (ideal for OEM integration), refined user software, resistance, reliability and an appropriate price. We do not offer cheap or low cost spectrometers but we can call them budget or economical spectrometers given their low price compared to their great value.

 

More information: ventas@procarelight.com / +34 605 024 420