Here we report on a hydrogen gas sensor comprised of Pt-WO3 nano-/micro- powder films, which were produced using nanosecond pulsed laser ablation and deposition on a silica glass substrate under atmospheric conditions. An all- optical non-contact method of probing its electromagnetic radiation transmittance in the near-IR 1.3 μm telecommunications frequency band was employed
for rapid ∼ 10 s timescale detection of low-concentration (below 4% by volume)
hydrogen gas admixtures. Discussion on optimizing the composition of the Pt- WO3 alloy and its processing conditions and temperatures for best performance is provided.