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: 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 terahertz laser suitable for emitting at least one first electromagnetic radiation, a first emission frequency of which is between 700 and 1200 GHz. The laser comprises an infrared laser source and a resonant cavity arranged to be optically pumped by the infrared laser source, the resonant cavity containing ammonia gas as an amplifier medium and having at least one configuration in which the resonant cavity is a resonant cavity at the first emission frequency. The infrared laser source is a continuous semiconductor laser source capable of exciting molecules of the amplifier medium from an initial energy level to at least one first excited energy level, the molecules of the amplifier medium placed in the first energy level being able to relax through a pure inversion transition for which the relaxation energy corresponds to the first emission frequency.

Abstract: A terahertz laser suitable for emitting at least one first electromagnetic radiation, a first emission frequency of which is between 700 and 1200 GHz. The laser comprises an infrared laser source and a resonant cavity arranged to be optically pumped by the infrared laser source, the resonant cavity containing ammonia gas as an amplifier medium and having at least one configuration in which the resonant cavity is a resonant cavity at the first emission frequency. The infrared laser source is a continuous semiconductor laser source capable of exciting molecules of the amplifier medium from an initial energy level to at least one first excited energy level, the molecules of the amplifier medium placed in the first energy level being able to relax through a pure inversion transition for which the relaxation energy corresponds to the first emission frequency.

Abstract: The invention relates to a light mixer for generating terahertz radiation, comprising a photodetector (PHD) coupled to an antenna (AT) for terahertz radiation, characterized in that the photodetector comprises a layer of photoconductive material capable of absorbing optical radiation, said layer having a thickness that is less than the absorption length of said radiation by the photoconductive material and being contained between an at least partially transparent so-called upper electrode and a reflective so-called lower electrode, said lower and upper electrodes comprising a resonant cavity for said optical radiation. The invention further relates to a terahertz radiation source comprising such a light mixer and to two laser radiation sources arranged to stack two laser radiation beams on the upper electrode of the photodetector. The invention also relates to the use of such a light mixer for generating terahertz radiation via light mixing.

Abstract: The invention relates to a light mixer for generating terahertz radiation, comprising a photodetector (PHD) coupled to an antenna (AT) for terahertz radiation, characterized in that the photodetector comprises a layer of photoconductive material capable of absorbing optical radiation, said layer having a thickness that is less than the absorption length of said radiation by the photoconductive material and being contained between an at least partially transparent so-called upper electrode and a reflective so-called lower electrode, said lower and upper electrodes comprising a resonant cavity for said optical radiation. The invention further relates to a terahertz radiation source comprising such a light mixer and to two laser radiation sources arranged to stack two laser radiation beams on the upper electrode of the photodetector. The invention also relates to the use of such a light mixer for generating terahertz radiation via light mixing.