Masers, the older cousin of the laser, are used as low noise signal amplifiers in deeps space communication and radio astronomy. They are most sensitive, low-noise detectors of faint microwave signals yet developed. Despite this the obscurity of masers in everyday applications is due to the stringent operating conditions - such as liquid helium refrigeration and high DC magnetic field - it require to function properly. Overcoming these various obstacles would pave the way for improvements such as more-sensitive chemical assays, more-precise determinations of biomolecular structure and function, and more-accurate medical diagnostics based on enhanced magnetic resonance spectrometers incorporating maser amplifiers and oscillators. Recent studies has shown that, Room temperature solid state maser can be achieved by optically pumping a verity of materials - the linear polyacenes molecules and nitrogen vacancy center in diamond - incorporated to a ring resonator that support whispering gallery modes. This talk is intend to give a birds eye view on the recent development in optically pumped solid state masers.
 Continuous-wave room-temperature diamond maser, J. D. Breeze et. al. Nature 2018 555,493–496, doi.org/10.1038/nature25970
 Molecular Design of a Room-Temperature Maser, Stuart Bogatko et. al. The Journal of Physical Chemistry C 2016 120, 8251-8260, doi.org/10.1021acs.jpcc.6b00150