Open AccessMicro-structured femtosecond laser assisted FBG hydrogen sensor
Author(s) -
Joseph Muna Karanja,
Yutang Dai,
Xinxing Zhou,
Bin Liu,
Minghong Yang
Publication year - 2015
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.031034
Subject(s) - materials science , femtosecond , hydrogen , optics , laser , hydrogen sensor , sensitivity (control systems) , fiber bragg grating , repeatability , fiber laser , optoelectronics , palladium , chemistry , wavelength , biochemistry , physics , organic chemistry , chromatography , electronic engineering , engineering , catalysis
We discuss hydrogen sensors based on fiber Bragg gratings (FBGs) micro-machined by femtosecond laser to form microgrooves and sputtered with Pd/Ag composite film. The atomic ratio of the two metals is controlled at Pd:Ag = 3:1. At room temperature, the hydrogen sensitivity of the sensor probe micro-machined by 75 mW laser power and sputtered with 520 nm of Pd/Ag film is 16.5 pm/%H. Comparably, the standard FBG hydrogen sensitivity becomes 2.5 pm/%H towards the same 4% hydrogen concentration. At an ambient temperature of 35°C, the processed sensor head has a dramatic rise in hydrogen sensitivity. Besides, the sensor shows good response and repeatability during hydrogen concentration test.