|
Electromagnetically induced grating (EIG) is an optical interference phenomenon where an interference pattern is used to build a dynamic spatial diffraction grating in matter. EIGs are dynamically created by light interference on optically resonant materials and rely on population inversion and/or optical coherence properties of the material. They were first demonstrated with population gratings on atoms.〔Mitsunaga et al., Phys. Rev. A 59, 4773 (1999)〕 EIGs can be used for purposes of atomic/molecular velocimetry, to probe the material optical properties such as coherence and population life-times,〔G.C.Cardoso, Phys. Rev. A 65, 033803 B (2002).〕 and switching and routing of light.〔Brown AW, Xiao, M, Opt. Lett. 30, 699 2005 ; Su XM, Ham BS, Dynamic control of the photonic band gap using quantum coherence Phys. Rev. A 71, 013821 (2005)〕 Related but different effects are thermally induced gratings and photolithography gratings. == Writing, Reading and Phase matching conditions for EIG diffraction == Figure 1 shows a possible beam configuration to write and read an EIG. The period of the grating is controlled by the angle . The writing and reading frequencies are not necessarily the same. E_B is referred as the "backward" reading beam and ER is the signal obtained by diffraction on the grating. The phase-matching conditions for the EIG for the plane-wave approximation is given by the simple geometric relation: , where the angles are given according to Fig. 2, and are the frequencies of the writing (W, W') and reading beam (R), respectively, and n is the effective index of refraction of the medium. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Electromagnetically induced grating」の詳細全文を読む スポンサード リンク
|