Question is related to High Pressure Geophysics Domain:
Low intense Raman spectra was observed for the sample around 1-10GPa (Pressure range) by using Diamond Anvil cell technique.
Past troubleshoot applied like laser alignment, pre-calibration, clean sample surface, laser power etc. Still no improvement any suggestion.
The question is not clear whether your sample is giving low Raman signal or after putting sample inside DAC you are getting poor signal?? Generally we are recording our ambient spectra with short working distance lenses, but for DAC mostly we will be working with long working distance (LWD) lenses for this condition if your laser power and time is same you will get lesser number of counts in LWD lenses. So when you are putting your sample inside DAC increase your scan time also check signal from the loaded sample before putting upper DAC. Also due to compression effects pressure dependent broending will be there depending on your sample. In this as you will increase pressure intensity will decrease at higher pressure. There are also other factors which will lead to intensity decrease at higher pressures.
It is not clearly stated that you see the signal strongly below 1GPa - is this the case or not?
I am only getting poor signal after putting the upper DAC. When I put the sample in lower DAC and take the spectra its proper. Also I have tried to increase the acquisition time still I am able to get the spectra of low intensity . There is broadening of the peak at high pressure for my study. So, with the current problem,it will be hard to see any sample spectra at high pressure. I see the signal below 1GPa but intensity is very low.
Generally we lose the intensity (10 times lower than ambient), when we load the sample inside DAC.Please make sure that you are getting enough intensity at ambient conditions to work with.Compare the intensity ratio of your sample inside and outside DAC.If you find major difference, then it might be due to property of your sample. We can expect the electronic transition at very low pressures (MPa regime) provided your number of peaks are same. Since you didnt mention about your sample, we cant conclude completely.
Since you didn't mention the nature of the sample, it is difficult to answer your question properly. Usually metallic samples show weak Raman signal. In some samples, you can try with different laser wavelength to get better signal. Also, optimize the laser power and ensure that laser doesn't burn the sample.
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