Room-Temperature Quasi-Continuous-Wave Pentacene Maser Pumped by an Invasive <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mi>Ce</mml:mi><mml:mo>:</mml:mo><mml:mi>YAG</mml:mi></mml:math> Luminescent Concentrator
Hao Wu, Xiangyu Xie, Wern Ng, Seif Mehanna, Yingxu Li, Max Attwood, Mark Oxborrow
Abstract
We present in this work a quasi-continuous-wave (cw) pentacene maser operating at 1.45 GHz in the Earth's magnetic field at room temperature with a duration of approximately 4 ms and an output power of up to $\ensuremath{-}25$ dBm. The maser is optically pumped by a cerium-doped yttrium-aluminum-garnet (YAG) ($\mathrm{Ce}:\mathrm{YAG}$) luminescent concentrator (LC), the wedge-shaped output of which is embedded inside a 0.1% pentacene-doped para-terphenyl (Pc:Ptp) crystal. The pumped crystal is located inside a ring of strontium titanate (STO) that supports a ${\mathrm{TE}}_{01\ensuremath{\delta}}$ mode of high magnetic Purcell factor. Combined with simulations, our results indicate that cw operation of pentacene masers at room temperature is perfectly feasible so long as excessive heating of the crystal is avoided.