{'fraction_non_alphanumeric': 0.02888086642599278, 'fraction_numerical': 0.0048134777376654635, 'mean_word_length': 5.303030303030303, '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}}
Nonlinear crystals for imaging and detection of mid-IR radiation

The mid-IR wavelength range, i.e. 2-25 μm, houses the vibrational spectra of most gasses and large molecules found in complex structures such as tissue, plastics or food. When designing an upconversion system for imaging or mid-IR detection, several aspects should be considered. Upconversion has several advantageous features which makes it an interesting option to consider for many mid-IR applications. Main advantages include, low-noise detection even at elevated temperatures, an almost instantaneous response time, phase preservation, and the ability to perform upconversion imaging. The χ(2) crystal properties impact the performance of the system significantly. Design aspects related to the choice of crystal as well as different applications is presented.