scholarly journals Polymer Based Whispering Gallery Mode Humidity Sensor

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2383 ◽  
Author(s):  
Ann Petermann ◽  
Thomas Hildebrandt ◽  
Uwe Morgner ◽  
Bernhard Roth ◽  
Merve Meinhardt-Wollweber

Whispering gallery mode (WGM) resonators are versatile high sensitivity sensors, but applications regularly suffer from elaborate and expensive manufacturing and read-out. We have realized a simple and inexpensive concept for an all-polymer WGM sensor. Here, we evaluate its performance for relative humidity measurements demonstrating a sensitivity of 47 pm/% RH. Our results show the sensor concepts’ promising potential for use in real-life applications and environments.

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1746
Author(s):  
Pauls Kristaps Reinis ◽  
Lase Milgrave ◽  
Kristians Draguns ◽  
Inga Brice ◽  
Janis Alnis ◽  
...  

We demonstrate a highly sensitive whispering gallery mode (WGM) relative humidity (RH) sensor based on a glycerol microdroplet. WGMs were excited using a 760 nm tunable semiconductor laser. We used free space coupling, which is effective when using a liquid resonator. A detailed analysis of different parameters influencing the sensor’s characteristics (sensitivity, hysteresis, resolution, stability, and temperature) is presented. The sensitivity of the sensor is one of the highest reported (2.85 nm/% RH in the range 50–70% RH with the resolution 1 × 10−4% RH). This type of humidity sensor has several advantages, such as high sensitivity, extended lifetime, good repeatability, and low cost, as well as the use of a non-toxic and environmentally friendly liquid.


Author(s):  
Qiulin Ma ◽  
Tobias Rossmann ◽  
Zhixiong Guo

An optical micro-coupling system of whispering-gallery mode usually consists of a resonator (e.g. a sphere) and a coupler (e.g. a taper). In this report, silica microspheres of 50–500 μm in diameter are fabricated by hydrogen flame fusing of an end of a single mode fiber or fiber taper. Fiber tapers are fabricated by the method of heating and pulling that meets an adiabatic condition. Taper’s waist diameter can routinely be made less than 1 μm and almost zero transmission loss in a taper is achieved which allows an effective and phase-matched coupling for a wide range sizes of microspheres. Both resonators and couplers’ surface microstructure and shapes are examined by scanning electronic microscopy. Three regimes of coupling are achieved, enabling a good flexibility to control Q value and coupling efficiency of a micro-coupling system. Whispering gallery mode shift is used to demonstrate a novel temperature micro-sensor. Its sensitivity determined from actual experimental results agrees well with the theoretical value. A concept of using the photon’s cavity ring down (CRD) in the microsphere to make a novel high-sensitivity trace gas micro-sensor is proposed. The CRD time constant when ammonia is chosen as the analyte gas is predicted using the simulated absorption lines.


2016 ◽  
Vol 52 (54) ◽  
pp. 8417-8419 ◽  
Author(s):  
Lingling Wang ◽  
Xiaochuan Duan ◽  
Wuyuan Xie ◽  
Qiuhong Li ◽  
Taihong Wang

A novel resistance type humidity sensor was fabricated using poly(ionic liquid)s, which exhibited high sensitivity, fast response, small hysteresis and good repeatability at a relative humidity (RH) in the range of 11–98%, making poly(ionic liquid)s as promising sensing materials for high-performance humidity sensors.


The Analyst ◽  
2017 ◽  
Vol 142 (6) ◽  
pp. 883-898 ◽  
Author(s):  
Angelo Bozzola ◽  
Sara Perotto ◽  
Francesco De Angelis

In this review we present the state of the art and the most recent advances in the field of optical sensing with hybrid plasmonic–photonic whispering gallery mode (WGM) resonators.


Author(s):  
Jesús S. Mondragón-Ochoa ◽  
José González-Rivera ◽  
Cigdem Toparli ◽  
Rizwana Khanum ◽  
Rakesh Singh Moirangthem ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7102
Author(s):  
Corneliu Doroftei ◽  
Liviu Leontie

This paper presents the synthesis of gadolinium aluminate (GdAlO3), an oxide compound with a perovskite structure, for applications as a capacitive and/or resistive humidity sensor. Gadolinium aluminate was synthesized by the sol-gel self-combustion method. This method allowed us to obtain a highly porous structure in which open pores prevail, a structure favorable to humidity sensors. Most of the materials studied as capacitive/resistive humidity sensors have significant sensitivities only with respect to one of these types of sensors. In the case of the studied gadolinium aluminate with p-type electric conductivity, the relative humidity of the air has a significant influence on both capacitive and resistive types of electric humidity sensors. The capacity increases about 10,000 times, and the resistance decreases about 8000 times as the relative humidity increases from 0 to 98%. The investigated gadolinium aluminate can be used successfully to obtain high-sensitivity capacitive and/or resistive humidity sensors.


Author(s):  
Matthew Frenkel ◽  
Marlon Avellan ◽  
Zhixiong Guo

Optical Whispering-Gallery Mode (WGM) resonators can be fabricated with very high quality factors allowing for their use as high resolution sensors in a myriad of fields ranging from quantum electro-dynamics (QED) to pressure sensing. In this paper, we focus on integrating WGM as a dynamic temperature measurement device. The WGM sensors are fabricated onto the heating element, instead of acting as an indirect temperature sensor, allowing for direct monitoring of an area of interest. An adaptation to the WGM theoretical model, to include the thermal expansion of the composite system, is discussed and analyzed.


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