LASING WITHOUT INVERSION AND ORIGIN OF GAIN IN A Λ SYSTEM
张登玉
LASING WITHOUT INVERSION AND ORIGIN OF GAIN IN A $\Lambda$ SYSTEM
ZHANG DENG-YU (张登玉)
中国物理B . 1997, (2): 92 -96 .  DOI: 10.1088/1004-423X/6/2/002