Chinese scientists build a laser weapon that can operate without cooling in Sahara Desert
Chinese researchers overcome decades-long challenge to build a laser that operates across 100-degree Celsius temperature swings

Their innovation hinges on some radical design choices, including 940-nanometre pump lasers with minimal thermal drift, directly injecting light via nine forward and 18 backward fibre-coupled diodes.
They also put pump combiners outside the resonator to isolate heat-sensitive components. Coiling ytterbium-doped fibre at around 8cm (3.1 inches) diameters helps to suppress parasitic lightwaves.
“We have achieved a technological breakthrough in the performance of wide-temperature operating fibre lasers,” wrote Chen and his colleagues in a peer-reviewed paper to be published in the Chinese-language journal Higher Power Laser and Particle Beams in July, now available online.
At the laser’s core lies a dual-clad optical resonator – 99 per cent reflective gratings at both ends sandwiching ytterbium-doped fibres. When pumped, ytterbium ions emit photons amplified into a lethal 1,080nm beam, filtered and collimated through quartz caps.