{'fraction_non_alphanumeric': 0.01651376146788991, 'fraction_numerical': 0.0, 'mean_word_length': 5.9113924050632916, '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}}
Precise photodetection with shot-noise-limit sensitivity for picosecond laser measurements: detection of small surface gradients with photodeflection technique

We present the simple and very effective radio frequency lock-in technique for precise measurements with cw-pumped mode-locked lasers. The technique is applied for the photodeflection transient spectroscopy that allowed to reach the sensitivity to surface displacement about one femtometer. We use the method for probing hypersound generation and propagation in a semiconductor plate.