All-Organic Waveguide Sensor for Volatile Solvent Sensing

Edgars Nitiss,Martins Rutkis,Andrejs Tokmakovs,Arturs Bundulis,Janis Busenbergs

doi:10.1007/s13320-019-0543-z

Abstract

An all-organic Mach-Zehnder waveguide device for volatile solvent sensing is presented. Optical waveguide devices offer a great potential for various applications in sensing and communications due to multiple advantageous properties such as immunity to electromagnetic interference, high efficiency, and low cost and size. One of the most promising areas for applications of photonic systems would be real-time monitoring of various hazardous organic vapor concentrations harmful to human being. The optical waveguide volatile solvent sensor presented here comprises a novel organic material applied as a cladding on an SU-8 waveguide core and can be used for sensing of different vapors such as isopropanol, acetone, and water. It is shown that the reason for the chemical sensing in device is the absorption of vapor into the waveguide cladding which in turn changes the waveguide effective refractive index. The presented waveguide device has small footprint and high sensitivity of the mentioned solvent vapor, particularly that of water. The preparation steps of the device as well as the sensing characteristics are presented and discussed.

Highlights

Investigations into sensors for volatile organic compound detection have grown greatly and are motivated by the number of applications where they can be used, such as in food or chemical industry, electronic noses, or safety concerning toxic ambient conditions
The advantages of optical waveguide sensors are that they are immune to electromagnetic interference, they can be used for remote monitoring, and they are small and have a low weight
We present an all-organic Mach-Zehnder interferometric (MZI) waveguide device comprising novel organic vapor sensing organic material used as a cladding on SU-8 waveguide core

Summary

Introduction

Investigations into sensors for volatile organic compound detection have grown greatly and are motivated by the number of applications where they can be used, such as in food or chemical industry, electronic noses, or safety concerning toxic ambient conditions. The gas concentration is calculated from the light propagation loss in the waveguide by employing absorption based sensing [3,4,5,6]. Typical waveguide is operated in the mid-infrared range in which absorption peaks for a wide variety of trace gases are located. Such devices require fine optimization as well as expensive light sources and detectors. Another used approach for sensing of various organic molecules in waveguide devices is Edgars NITISS et al.: All-Organic Waveguide Sensor for Volatile Solvent Sensing the Raman spectroscopy [7]. Due to low Raman scattering cross-sections, the signals are typically weak and require using long optical waveguides

Methods

Results

Conclusion