Abstract: An optical fibre for an ultrafast laser endoscope including at least the following structures: a hollow core, the periphery of which has an order of symmetry of at least six when considering axes of symmetry passing through the centre of the core and through the centre of convex shapes, seen from the centre of the core, the convex shapes at least partly making up the periphery of the core; an intermediate layer of cellular structure surrounding the core; a light conducting peripheral structure surrounding the intermediate layer of cellular structure; and an outer sheath surrounding the light-conducting peripheral structure. A particular advantage of the optical fibre is that it optimizes the emission of a high-power flux associated with fluorescence collection.

Abstract: An optical fibre for an ultrafast laser endoscope including at least the following structures: a hollow core, the periphery of which has an order of symmetry of at least six when considering axes of symmetry passing through the centre of the core and through the centre of convex shapes, seen from the centre of the core, the convex shapes at least partly making up the periphery of the core; an intermediate layer of cellular structure surrounding the core; a lightconducting peripheral structure surrounding the intermediate layer of cellular structure; and an outer sheath surrounding the light-conducting peripheral structure. A particular advantage of the optical fibre is that it optimizes the emission of a high-power flux associated with fluorescence collection.

Abstract: A hollow core photonic crystal fiber (HCPCF) having a wavelength of operation, the HCPCF comprising: a core region having a first refractive index; a cladding region surrounding the core region and comprising a plurality of microcapillaries arranged in a transverse structure having a pitch, the pitch of the structure being at least five times larger than the wavelength of operation, the cladding region having a second refractive index higher than the first refractive index.

Abstract: An optical assembly includes a gas cell and an optical fiber portion in which the gas cell is contiguously attached to the optical fiber portion. The gas cell can be made, for example from hollow-core photonic crystal fiber (HC-PCF).

Abstract: An optical fibre is provided having a fibre cladding around a longitudinally extending optical propagation core. The cladding has a reflection region of a varying refractive index in the longitudinal direction.

Abstract: An optical assembly includes a gas cell and an optical fibre portion in which the gas cell is contiguously attached to the optical fibre portion. The gas cell can be made, for example from hollow-core photonic crystal fibre (HC-PCF).

Abstract: A hollow core photonic crystal fibre (HCPCF) having a wavelength of operation, the HCPCF comprising: a core region having a first refractive index; a cladding region surrounding the core region and comprising a plurality of microcapillaries arranged in a transverse structure having a pitch, the pitch of the structure being at least five times larger than the wavelength of operation, the cladding region having a second refractive index higher than the first refractive index.

Abstract: An optical wave generator comprising a first-level Raman sideband generator (RSBG). The first-level RSBG comprises a first hollow-core photonic crystal fibre HCPCF (203) arranged to be filled with a Raman active gas and a first two-pump continuous wave (CW) laser source (200) having a first pump laser beam (201) at a first frequency and a second pump laser beam (202) at a second frequency, the laser source being arranged to excite the first HCPCF to generate a Raman sideband spectrum comprising a first plurality of spectral components.