Abstract

We proposed the extremely compact beans-size snap-shot mid-infrared spectroscopy that will be able to be built in smartphones. And also the easy preparation method of thin-film samples generated by ultrasonic standing wave is proposed. Mid-infrared spectroscopy is able to identify material components and estimate component concentrations quantitatively from absorption spectra. But conventional spectral instruments were very large-size and too expensive to incorporate into daily life. And preparations of thin-film sample were very troublesome task. Because water absorption in mid-infrared lights is very strong, moisture-containing-sample thickness should be less than 100[μm]. Thus, mid-infrared spectroscopy has been utilized only by analytical experts in their laboratories. Because ultrasonic standing wave is compressional wave, we can generate periodical refractive-index distributions inside of samples. A high refractive-index plane is correspond to a reflection boundary. When we use a several MHz ultrasonic transducer, the distance between sample surface and generated first node become to be several ten μm. Thus, the double path of this distance is correspond to sample thickness. By combining these two proposed methods, as for liquid samples, urinary albumin and glucose concentrations will be able to be measured inside of toilet. And as for solid samples, by attaching these apparatus to earlobes, the enhancement of reflection lights from near skin surface will create a new path to realize the non-invasive blood glucose sensor. Using the small ultrasonic-transducer whose diameter was 10[mm] and applied voltage 8[V], we detected the internal reflection lights from colored water as liquid sample and acrylic board as solid sample.

© 2017 SPIE