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We present a polymer fibre Bragg grating sensor and its sensitivity to gamma radiation by observing the reflected spectral profile. The Bragg grating is femtosecond inscribed within a perfluorinated CYTOP fibre and the alteration of the Bragg wavelength corresponds to the total radiation dose received. Over a total dose of 41 k Gy, the fibre demonstrates a sensitivity of − 26.2 p m / k Gy and a resolution of 40 Gy. Under active consideration for the instrumentation of nuclear waste repositories, this study gives a better understanding of the effects of gamma radiation upon Bragg gratings in CYTOP fibres.

Photo-acoustic imaging, also known as opto-acoustic imaging, has become a widely popular modality for biomedical applications. This hybrid technique possesses the advantages of high optical contrast and high ultrasonic resolution. Due to the distinct optical absorption properties of tissue compartments and main chromophores, photo-acoustics is able to non-invasively observe structural and functional variations within biological tissues including oxygenation and deoxygenation, blood vessels and spatial melanin distribution. The detection of acoustic waves produced by a pulsed laser source yields a high scaling range, from organ level photo-acoustic tomography to sub-cellular or even molecular imaging. This review discusses significant novel technical solutions utilising photo-acoustics and their applications in the fields of biomedicine and life sciences.

We demonstrate the Bragg gratings inscription in the 850 nm spectral region by using trans-4-stilbenemethanol (TS)-doped poly (methyl methacrylate) (PMMA) step-index optical fiber and a 248 nm krypton fluoride (KrF) excimer laser system. The gratings inscription only takes 0.4 second. A detailed study of the grating fabrication process using different pulse repetition rates is also reported. Additionally, temperature, humidity and strain sensitivities are measured to demonstrate the potentiality of these components for different sensing applications.

We demonstrate a chirped microstructured polymer fiber Bragg grating based on taper technology for strain sensing application. The effective bandwidth of the grating is dependent on strain and remains practically constant with respect to temperature and humidity changes. We report a sensitivity of 0.90 pm/µε for the central wavelength under stable temperature and humidity values. The 3-dB bandwidth of the grating has been measured under different temperature and humidity conditions.