{'fraction_non_alphanumeric': 0.039832285115303984, 'fraction_numerical': 0.012578616352201259, 'mean_word_length': 4.623529411764705, '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}}
Optical two-photon absorption in GaAs measured by optical pump-terahertz probe spectroscopy

A novel scheme of optical pump-THz probe experiments was used to study the nonlinear absorption in GaAs. The crystal was excited by ultrashort laser pulses with wavelength 810 nm and fluences up to 4.2 mJ/cm/sup 2/, for which the single-photon absorption (SPA) saturates and the two-photon absorption (TPA) dominates. The TPA coefficient /spl beta/ and its anisotropy were determined.