Deconvolve absorption from this spectrometer signal

[anpl]

TL;DR Summary

I have a monochromatic laser and a tissue, and I want to measure the absorption with a spectrometer. What absorption do I use?

Hello all,

I have a monochromatic laser peaking at 808 nm and some non-scattering sample.
I want to measure the absorption with a spectrometer.

I can use the Beer-Lambert law to do this, but since it is a monochromatic laser I have some doubts.

I could do a weighted-average, taking into account the initial laser intensity profile. But could somebody please point me to the correct distribution and way to deconvolve the noise from the signal? Or am I thinking wrong somehow?

Thank you in advance for your input!

 

[Tom.G]

Not really my field, this is to hopefully get things started.

How about comparing Area Under Curve (AUC) both with and without the sample. Bandwidth perhaps at the 50% or 10% of the peak amplitude wavelengths without the sample. The 50% points are usually referred to as FWHM, Full Width Half Max, points.

Also try a Google search for approaches commercially available.
https://www.google.com/search?&q=identify+material+by+spectrometer
Anyone else have some input?

 

[Henryk]

Summary: I have a monochromatic laser and a tissue, and I want to measure the absorption with a spectrometer. What absorption do I use?

I have a monochromatic laser peaking at 808 nm and some non-scattering sample.
I want to measure the absorption with a spectrometer

Well, you want to use two thing designed to never worked together. A laser produces a monochromatic light. A spectrometer let's you measure the intensity of a light as a function of an wavelength.
Yes, you can set your spectrometer to the wavelength of the laser and measure the light intensity with and without your sample, take the ratio and get your absorption value at one wavelength - that of the the laser.
Of course, to do that, you don't need a spectrometer, just a light detector that respond at the wavelength of the laser.
Or, get a incandescent light, and use the spectrometer to get the absorption spectrum, i.e. the absorption coefficient as a function of a wavelength.