{'fraction_non_alphanumeric': 0.023516237402015677, 'fraction_numerical': 0.005599104143337066, 'mean_word_length': 5.622222222222222, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Fourth-order coherent Raman microspectroscopy for detection of material symmetry

Coherent Raman scattering provides chemical imaging by using molecular vibrational information sensitive to molecular structure. To add another information of martial symmetry, we propose using fourth order coherent Raman scattering for imaging, because the even order nonlinear phenomenon is forbidden for centro-symmetric material. We have developed a multiplex fourth order coherent Raman scattering microscopy system using a femtosecond laser. A narrowband beam of 17 cm-1 bandwidth and a broadband beam generated by a photonic crystal fiber enables to obtain a spectrum of fourth order coherent Raman scattering at once. We demonstrate the fourth order coherent Raman, hyper-Raman and second harmonics of trans-4'-(dimethylamino)-N-methyl-4- stilbazolium tosylate crystal by using the developed microscope.