{'fraction_non_alphanumeric': 0.02096069868995633, 'fraction_numerical': 0.00611353711790393, 'mean_word_length': 5.945454545454545, '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}}
On-chip optofluidic grating spectrograph for biomedical applications

This paper presents a liquid metal based on-chip optofluidic grating spectrograph integrated with polydimethylsiloxane (PDMS) microfluidics for biomedical applications such as handheld fluorescence-actuated cell sorting, fluorescence immunosensing and Raman spectroscopy. We designed a Czerny-Turner spectrograph with 1.4nm spectral resolution, 300nm FSR and a footprint of 1cm by 2cm. The spectrograph structure was fabricated in PDMS using conventional replica molding soft lithography, and then filled with room temperature liquid metal, Gallium-Indium-Tin Alloy. The material and fabrication method is fully compatible with PDMS microfluidics, which allowed us to integrate a sheath flow based microfluidic cell focusing system with the spectrograph on the same substrate. This integration represents an important step towards a handheld flow cytometer. In addition, as a new class of on-chip optofluidic components, liquid metallic optical elements such as mirrors, gratings and pinholes will likely find other applications for building miniaturized optofluidic systems.