Miniature quartz tuning fork-based broad spectral coverage and high detectivity infrared spectroscopy

Abstract

This paper reports a type of detector based on the thermoelastic effect of a miniature quartz tuning fork (mQTF) for infrared spectroscopy applications. Instead of using a pyroelectric infrared detector, a mQTF with a resonant frequency of ∼45 kHz was adopted as a detector for infrared light signal collection. To explore the capabilities of this technique, measurement of infrared absorption spectra of samples was conducted, and the effect of scattered light on the sensitivity was investigated. The experimental results indicate that the mQTF detector is sensitive to infrared radiation within a wide range of wavelengths, and packaging the mQTF could increase the sensitivity and signal-to-noise ratio (SNR) by 2.54, and 2.87 times, respectively. The infrared transmission spectrum of polystyrene (PS), polyethylene (PE) have been measured by the mQTF detector, and the experimental data show that the infrared characteristic absorption peaks appears in the same position as commercial pyroelectric detector. Finally, mid-infrared spectroscopy of acetone gas was measured by the mQTF with highprecision. It is worth noting that this is the first study of using the mQTF-based photodetector for gas phase infrared spectroscopy, the mQTF exhibits its cost-effectiveness, sensitivity, and broadband optical response advantages, could be used for qualitative analysis of components by the infrared spectrum.