A four-level atomic system with a closed interaction loop connected by two coherent driving fields and a microwave field is investigated. The results show that inversionless gain can be achieved on a higher frequency ...A four-level atomic system with a closed interaction loop connected by two coherent driving fields and a microwave field is investigated. The results show that inversionless gain can be achieved on a higher frequency transition outside the closed interaction loop, and the gain behaviour can be modulated by the phase of the closed loop as well as the amplitude of the microwave field. The phase sensitivity property in such a scheme is similar to that in an analogous configuration with spontaneously generated coherence, but it is beyond the rigorous condition of near-degenerate levels with non-orthogonal dipole moments. Therefore this scheme is much more convenient in experimental realization.展开更多
A three-level medium is the simplest and most suitable model for understanding the physical mechanisras of amplification without inversion (AWI). Various analyses were presented for all possible resonant three-level c...A three-level medium is the simplest and most suitable model for understanding the physical mechanisras of amplification without inversion (AWI). Various analyses were presented for all possible resonant three-level configurations. Recently, P. Mandel et al. have studied the AWI in three-level ∧ model for general nonresonant case and obtained the condition for establishing AWl. In our note the inversionless amplification of a monochromatic field in a nonresonant three-level ∧ medium will be investigated.展开更多
Our study shows that for the copropagating probing and driving fields, the gain without inversion doesn't monotonously decrease or increase with the increasement of Doppler width. When the driving field is resonan...Our study shows that for the copropagating probing and driving fields, the gain without inversion doesn't monotonously decrease or increase with the increasement of Doppler width. When the driving field is resonant, at a suitable Doppler width, we can get a maximum value of the gain without inversion, which is much larger than that obtained when Doppler broadening is absent.展开更多
基金Project supported by the Natural Science Foundation of Guangdong Province （Grant No 05301018）, the Research and Development Fund of Shenzhen University, China （Grant No 200549）, and the National Natural Science Foundation of China （Grant Nos 10334010 and 10404009）.
文摘A four-level atomic system with a closed interaction loop connected by two coherent driving fields and a microwave field is investigated. The results show that inversionless gain can be achieved on a higher frequency transition outside the closed interaction loop, and the gain behaviour can be modulated by the phase of the closed loop as well as the amplitude of the microwave field. The phase sensitivity property in such a scheme is similar to that in an analogous configuration with spontaneously generated coherence, but it is beyond the rigorous condition of near-degenerate levels with non-orthogonal dipole moments. Therefore this scheme is much more convenient in experimental realization.
文摘A three-level medium is the simplest and most suitable model for understanding the physical mechanisras of amplification without inversion (AWI). Various analyses were presented for all possible resonant three-level configurations. Recently, P. Mandel et al. have studied the AWI in three-level ∧ model for general nonresonant case and obtained the condition for establishing AWl. In our note the inversionless amplification of a monochromatic field in a nonresonant three-level ∧ medium will be investigated.
基金This work wass,IPPorted by theN战ional Natural Science foundation of China under Grant No.69978011 and the Natural Science Foundation of Shandong Province under Grant No.Y2001A07.
文摘Our study shows that for the copropagating probing and driving fields, the gain without inversion doesn't monotonously decrease or increase with the increasement of Doppler width. When the driving field is resonant, at a suitable Doppler width, we can get a maximum value of the gain without inversion, which is much larger than that obtained when Doppler broadening is absent.
