Experimental realization of a two-photon laser in strongly driven potassium atoms
Novel quantum oscillators consisting of strongly driven potassium atoms contained in a high-finesse optical resonator were examined. Two-photon amplification arose from laser-driven resonant scattering between magnetic hyperfine levels. A novel configuration using different states of polarization and an orthogonal beam geometry allowed discrimination between the numerous gain mechanisms. This configuration suppressed competing phase-matched wave-mixing processes, which was crucial to realize an ideal two-photon amplifier.