{'fraction_non_alphanumeric': 0.025078369905956112, 'fraction_numerical': 0.007836990595611285, 'mean_word_length': 5.326732673267327, '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}}
Efficient parametric generation of femtosecond IR radiation in a system utilising the properties of group-velocity matching

A scheme for an injection optical parametric oscillator (OPO) pumped by a forsterite laser is examined (λ = 1.25 μm). The possibility of efficient generation of femtosecond pulses in the mid-IR range is demonstrated for RbTiOAsO4 and AgGaSe2 crystals, ensuring group-velocity matching of the interacting waves. A two-stage system designed to increase the contrast of the femtosecond laser radiation by parametric amplification and generation of the sum frequency in the group-velocity-matching regime is proposed.