负Goos-H？nchen位移的理论与实验研究

1947年Goos和H？nchen发现,当电磁波束在玻璃/空气界面全反射时,在返回玻璃内部时有一项发生在入射面内的纵向位移；我们称之为正位移。实际上,稳态相位法的计算表明,位移可以为正、为零,甚至为负。由于界面上的表面波可以是前向型的和后向型的,携带的功率向着不同方向；故当激发起后向型表面波时就可获得入射波束的负位移。在多层结构中,当入射波束波矢的切向分量与表面波传播常数一致时,会发生类谐振现象并导致位移增大。〈br〉 在一般情况下,当光束入射到金属表面,TM极化时GHS为负,并且绝对值比TE极化时大得多。但我们在微波的实验研究表明,在使用金属时可以在TE极化时发生负位移。实验时在全反射界面处为纳米级金属膜,是厚度30nm和60nm的铝膜,它蒸镀在厚18μm聚乙烯膜上。实验还发现,当改变入射角θ1并使之达到约qθ1c（θ1c为全反射临界角,q＆gt;1）出现类谐振现象,GHS的绝对值可达（5~7）cm。目前尚缺少对这些结果的理论解释。

Theoretical and Experimental Study of the Negative Goos-H？nchen Shifts

It has been shown by Goos and H？nchen in 1947 that electro-magnetic wave beam totally re-flected from a glass-air interface suffers a longitudinal displacement in the plane of incidence before re-entry into the glass,we say this situation to be positive GH shifts. In fact,the longitudinal displacement as computed by the application of the stationary phase method can be positive,zero or negative. The sur-face waves may be of the forward or the backward type and they carry power in opposite directions in the interface. And then,a negative shift of the incident beam is obtained when the backward surface waves are excited. In a layered structure,when the tangential component of the wave vector of incident beam co-incides with the propagation constant of the surface wave,the resonance-like phenomenon leading to a large enhancement of the beam shift. 〈br〉 In common cases when a light beam incident on a metal surface,the GHS for TM polarized light in metals is negative and much bigger than the positive shift for TE polarized light. But a experimental re-search of the GHS was performed by our team with microwaves,the result was that the shifts for TE polar-ized wave in metals is negative---dataes of the total reflection influenced by nano metal-films deposite on the total reflecting surface,and the Al-films were 30nm and 60nm thick and were vapor deposited on polyethylene films of 18μm thickness. When the incidence angleθ1 near the value of qθ1c （θ1c is the critical angle of total reflection,q＆gt;1）,it show a resonance-like behavior,the GHS has a strong maximum of （5~7）cm absolute-ly. There is no exact theory for explain these effects,now.