  Quantum electronics operating in the microwave domain are burgeoning and
becoming essential building blocks of quantum computers, sensors and
communication devices. However, the field of microwave quantum electronics has
long been dominated by the need for cryogenic conditions to maintain the
delicate quantum characteristics. Here we report on a solid-state hybrid
system, constituted by a photo-excited pentacene triplet spin ensemble coupled
to a dielectric resonator, that is for the first time capable of both coherent
microwave quantum amplification and oscillation at X band via the masing
process at room temperature. By incorporating external driving and active
dissipation control into the hybrid system, we achieve efficient tuning of the
maser emission characteristics at around 9.4 GHz, which is key to optimizing
the performance of the maser device. Our work not only pushes the boundaries of
the operating frequency and functionality of the existing pentacene masers, but
also demonstrate a universal route for controlling the masing process at room
temperature, highlighting opportunities for optimizing emerging solid-state
masers for quantum information processing and communication.
