From LASER to QASER: Light Amplification by Superradiant Emission of Radiation
讲座名称：
From LASER to QASER: Light Amplification by Superradiant Emission of Radiation
讲座时间：
2013-06-06
讲座人：
Anatoly A. Svidzinsky
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校区：
兴庆校区
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讲座内容：
讲座名称： From LASER to QASER: Light Amplification by Superradiant Emission of Radiation
讲座时间： 2013年6月06日（周四）下午 4:30-6:00（3:30-4:20pm 座谈）
讲座地点： 中1-3113
讲座人： Anatoly A. Svidzinsky, Texas A&M University,
讲座内容： A laser generates light through stimulated emission of radiation and requires population inversion. Quantum interference can yield lasing without inversion which could be useful for making lasers at shorter wavelength, but still requires some atomic population in the excited state. First I will discuss lasing without inversion occurring on a superradiant time scale much shorter than spontaneous decay and collision times. This allows us to take advantage of coherence effects, but requires investigation of the system’s dynamics in transient regime far from steady state. Then I will present a new kind of quantum amplifier based on collective superradiant emission which does not need any population in the excited state. In such a device, light amplification at high frequency (e.g. XUV) atomic transition occurs due to parametric resonance between the driving (e.g. Infrared) field and collective superradiant oscillations of the atomic polarization. This can result in efficient conversion of intense Infrared light into the XUV. To achieve gain one must suppress a time-dependent Stark shift due to the driving field. The resulting superradiant amplifier is many orders of magnitude more efficient than the usual multiphoton resonant excitation and holds promise for a new kind of generator of high frequency coherent radiation. I will also discuss a physically appealing explanation of Quantum Amplification by Superradiant Emission of Radiation (QASER) operation in terms of coupled classical oscillators.
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