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Photo thermal spectrometer

2D scheme of the set-up fig.1 

3D scheme of the set-up fig.2 

Photo of the set-up fig.3 

Visualized beams fig.4 

XY scan small fig.5 

Filter absorption map fig.6 

Lock-In parameters fig.7 

Sample's profile fig.8

Hi-precision measurements. What do you think of when you hear these words? Reliability? Quality? Repeatability? Accuracy? All this can not be achieved if measurements are performed by humans. So the next thing you'll think of is machine control. Only complete automation with rigid sequence of actions can guarantee hi-precision measurements.

In research it is often impossible to tell in advance what steps should be taken to measure process's parameters.. Such measurements involve creativeness, intuition and passion. Processors and microcontrollers can not provide these things. Only humans can. It means that system should be controlled manually. But this statement contradicts with the previous one.

This contradiction is very hard to overcome if one only thinks in terms of machines versus humans. In “either or” situations, there is no winner. In machine centered approach final system would inevitably be too rigid to accomplish unpredicted types of measurements and in human centered – to unreliable.

There is another approach to the solution of this problem – task centered. Supply the researcher with tools that extend his capabilities – with the reliability of an automated solution and the repeatability of a machine.

XInstruments automated the Photo Thermal Spectrometer. This device uses the photo-induced absorbance (PIA) phenomenon to measure small absorbance of the transparent mediums such as dielectric mirrors, thin films, optical mounts, etc. PIA method is based on measurement of probe's laser beam attenuation changes in the sample, which is caused by the local thermal heating of the sample under the radiation of a pump laser. The main problems to overcome were precision alignment of laser beams (one of which was invisible to the human eye), accurate sample positioning and speed of test.

XInstruments developed a set of tools, integrated in one application, allowing the researcher to visualize several laser beams (including infrared) on the screen, position the sample with 1.25 mkm precision and to perform test time efficiently. As the result the system allows to measure absorptions as small as 10 -5 cm -1 , obtain the sample's map of absorption with the precision of 2 mkm and to perform the scan of 10x10 cm area with 2 mkm precision in only 10 minutes.

If you are interested in custom software, please contact us. If you want to know more about our work, please look into our Projects folder.