Terahertz optoacoustic detection of aqueous salt solutions

Liwen Jiang; Ke Zhang; Yixin Yao; Shuai Li; Jiao Li; Zhen Tian; Weili Zhang

doi:10.1016/j.isci.2022.104668

Terahertz optoacoustic detection of aqueous salt solutions

iScience. 2022 Jun 26;25(7):104668. doi: 10.1016/j.isci.2022.104668. eCollection 2022 Jul 15.

Authors

Liwen Jiang^{1

2

3}, Ke Zhang^{1

2

3}, Yixin Yao^{1

2

3}, Shuai Li¹, Jiao Li¹, Zhen Tian^{1

2

3}, Weili Zhang⁴

Affiliations

¹ School of Precision Instruments and Optoelectronics Engineering, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin 300072, China.
² Center for Terahertz Waves, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin 300072, China.
³ Key Laboratory of Optoelectronics Information and Technology (Ministry of Education), No.92 Weijin Road, Nankai District, Tianjin 300072, China.
⁴ School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, OK 74078, USA.

Abstract

Terahertz radiation has been used to detect aqueous salt solutions; however, strong absorption of water in terahertz regime limits the application of traditional terahertz techniques. Here, we present a novel method in analyzing aqueous salt solutions via terahertz optoacoustics. Terahertz optoacoustic signals can be manipulated by temperature control, which allows the dampening of water background and providing more information of solute. We demonstrate that dynamic and continuous terahertz optoacoustic detections of salt solutions with different solutes, concentrations, temperatures, and terahertz spectral frequencies shows the significant potential of this method in distinguishing different salt solutions and quantitatively analyzing salt concentrations. Terahertz optoacoustics may be a powerful tool for quantitative and label-free detection of aqueous salt solutions to further study the complicated aqueous solutions in terahertz regime.

Keywords: applied sciences; optics; physics.