Ultra-sensitive all-fibre photothermal spectroscopy with large dynamic range

Abstract

Photothermal interferometry is an ultra-sensitive spectroscopic means for trace chemical detection in gas- and liquid-phase materials. Previous photothermal interferometry systems used free-space optics and have limitations in efficiency of light–matter interaction, size and optical alignment, and integration into photonic circuits. Here we exploit photothermal-induced phase change in a gas-filled hollow-core photonic bandgap fibre, and demonstrate an all-fibre acetylene gas sensor with a noise equivalent concentration of 2 p.p.b. (2.3 × 10−9 cm−1 in absorption coefficient) and an unprecedented dynamic range of nearly six orders of magnitude. The realization of photothermal interferometry with low-cost near infrared semiconductor lasers and fibre-based technology allows a class of optical sensors with compact size, ultra sensitivity and selectivity, applicability to harsh environment, and capability for remote and multiplexed multi-point detection and distributed sensing.

Distributed photothermal spectroscopy in microstructured optical fibers: towards high-resolution mapping of gas presence over long distances

“…The temperature changes along the fiber are determined with a fast and high-resolution distributed sensor based on chirped-pulse reflectometry [23]. Although phase-sensitive optical time domain reflectometry has previously been suggested for gas sensing [9], our work represents the first time that such a distributed photothermal measurement is actually experimentally demonstrated. Moreover, the system proposed here does not require a coherent detection setup, like the one proposed by W. Jin et al Wavelength modulation in the heating laser allows to easily discriminate the ambient temperature variations from the actual presence of gas.…”

“…In particular, fiber-optic based chemical sensors have shown interesting properties either for the detection of specific gases in air [7][8][9] or chemicals in solution [10]. In a fiber-optic chemical sensor, the glass, dielectric fiber, conveys the measuring signal and typically serves as the support of the transduction material, keeping any required electronic component separated from the measurand substance.…”

Partially reduced graphene oxide based FRET on fiber optic interferometer for biochemical detection

“…Such a prGO based 'FRET on fiber' configuration, bridging the FRET and the fiber-optic sensing technology, may serve as a platform for the realization of series of integrated 'FRET on Fiber' sensors for on-line environmental, chemical, and biomedical detection, with excellent compactness, high sensitivity, good selectivity and fast response Biochemical detection with both high sensitivity and selectivity is of great importance in medical, chemical, environmental and security areas. During the past decades, various optical biochemical detection methods based on diverse technologies have been reported and still developing fast [1][2][3][4][5][6][7] . In particular, the fluorescence resonance energy transfer (FRET) is a highly popular method due to its biochemical universality and naturally exceptional selectivity [8][9][10] .…”

“…During the past decades, various optical biochemical detection methods based on diverse technologies have been reported and still developing fast [1][2][3][4][5][6][7] . In particular, the fluorescence resonance energy transfer (FRET) is a highly popular method due to its biochemical universality and naturally exceptional selectivity [8][9][10] .…”

Silicon and silicon nitride photonic circuits for spectroscopic sensing on-a-chip [Invited]

“…This has led to the development of a range of optical biosensors based on emission, absorption, and refractometry. Although optical sensing can be performed in different platforms such as optical fibers [1], waveguides [2], and bulk optics [3], an integrated photonics approach has significant advantages. First, integrated photonics enables miniaturization and integration of active and passive optical components.…”