Abstract: An integrated photoacoustic transducer, sensing system and method for assisting in sensing a concentration of a species in a fluid such that the integrated photoacoustic transducer includes a waveguide structure. The waveguide structure has an optical resonance spectrally overlapping a spectral absorption line or band of the species. The photoacoustic transducer includes at least one acoustic cavity formed in a portion of the waveguide structure and configured for receiving the fluid for sensing comprising the species. The at least one acoustic cavity has an acoustic resonance spectrally overlapping with a harmonic of a modulation frequency. At least one acoustic transducer comprising a deformable mechanical portion is included in the photoacoustic transducer.

Abstract: A photonic integrated circuit-based dual frequency comb source, an integrated system for dual comb spectroscopy and corresponding method are disclosed. The dual comb source includes, on a same substrate of the photonic integrated circuit, a first and second semiconductor integrated mode-locked laser, a master laser, and connection arrangement between the master laser and each of the first and second mode-locked laser. The master laser is configured for generating a lasing line for simultaneous optical injection-locking of the first and second mode-locked laser, the first and second mode-locked laser are configured for generating a first and second frequency comb respectively, and the connection arrangement is suitable for coherently transferring lasing light from the master laser to each mode-locked laser. The mode-locked lasers include a gain section and a saturable absorber section to provide mode-locking, and an extended optical cavity formed in the substrate.

Abstract: An optical frequency comb device includes: an optical waveguide; a first mirror disposed at a first position in the optical waveguide; a second mirror disposed at a second position different from the first position, in the optical waveguide; a gain medium and a saturable absorber which are disposed between the first mirror and the second mirror; and a controller that fixes one of a repetition frequency and a carrier-envelope offset frequency of an optical frequency comb output from an end of the optical waveguide, and changes the other of the repetition frequency and the carrier-envelope offset frequency.

Abstract: An integrated photoacoustic transducer, sensing system and method for assisting in sensing a concentration of a species in a fluid such that the integrated photoacoustic transducer includes a waveguide structure. The waveguide structure has an optical resonance spectrally overlapping a spectral absorption line or band of the species. The photoacoustic transducer includes at least one acoustic cavity formed in a portion of the waveguide structure and configured for receiving the fluid for sensing comprising the species. The at least one acoustic cavity has an acoustic resonance spectrally overlapping with a harmonic of a modulation frequency. At least one acoustic transducer comprising a deformable mechanical portion is included in the photoacoustic transducer.