Improving the Sensitivity of Existing Electro-Optic Sampling Setups by Adding Brewster Plates: Tests of the Strategy at SOLEIL
Résumé
For improving the sensitivity of electro-optic sampling (EOS), several techniques are used. Operation of the set of polarizing elements "close to extinction" is a technique used routinely for obtaining high responsivity (i.e., a large output signal for a given input electric field). This technique is widely used for monitoring electron bunches in linear accelerators and FELs. We show that a simple modification of these EOS systems enables to increase further the SNR, by cancelling out the laser noise. The idea is to introduce a set of Brewster plates, following the idea Ahmed, Savolainen and Hamm [1] in the EOS path, and performing balanced detection. We present detailed tests of this type of upgrade on the PhLAM-SOLEIL EOS system, destined to studies of THz CSR pulse dynamics [2].