  Hollow core antiresonant fibers offer new possibilities in the near infrared
and visible spectral range. I show here that the great flexibility of this
technology can allow the design and fabrication of hollow core optical fibers
with an extended transmission bandwidth in the near infrared and with very low
optical attenuation in the visible wavelength regime. A very low attenuation of
175dB/km at 480nm is reported. A modification of the design of the studied
fibers is proposed in order to achieve fast-responding gas detection.
