  The synthesis of multiple narrow optical spectral lines, precisely and
independently tuned across the near- to mid-infrared (IR) region, is a pivotal
research area that enables selective and real-time detection of trace gas
species within complex gas mixtures. However, existing methods for developing
such light sources suffer from limited flexibility and very low pulse energy,
particularly in the mid-IR domain. Here, we introduce a new concept based on
the gas-filled anti-resonant hollow-core fiber (ARHCF) technology that enables
the synthesis of multiple independently tunable spectral lines with high pulse
energy of >1 {\mu}J and a few nanoseconds pulse width in the near- and mid-IR
region. The number and wavelengths of the generated spectral lines can be
dynamically reconfigured. A proof-of-concept laser beam synthesized of two
narrow spectral lines at 3.99 {\mu}m and 4.25 {\mu}m wavelengths is
demonstrated and combined with photoacoustic (PA) modality for real-time SO2
and CO2 detection. The proposed concept also constitutes a promising way for IR
multispectral microscopic imaging.
