Electromagnetically induced holographic imaging

Gain Assisted Raman Induced Classical and Quantum Talbot Imaging

“…One of the two beams that are moving along the reference path and other one along the path where gain assisted atomic medium (object beam) is placed and they will meet again at the detector $$D$$, where the intensity of the interfering beams is recorded. By solving the Maxwell's equation, transmission spectrum after passing through the gain assisted atomic medium can be obtained as [ 42 ] $$$$\begin{equation} \mathcal {E}(x,z,L)=\mathcal {E}(x,z,0)\text{Exp}[-\eta (x,z)L+i\zeta (x,z)L], \end{equation}$$$$where $$\eta (x,z)$$ is associated with absorption and $$\zeta (x,z)$$ is associated with phase modulation. The optically transmitted light intensity of gain assisted atomic system is represented by $$E(x,z,L)$$ in traditional imaging techniques, while $$\mathcal {E}(x,z,0)$$ represents the component of the beam pattern before entering the atomic medium.…”

“…where the intensity of the interfering beams is recorded. By solving the Maxwell's equation, transmission spectrum after passing through the gain assisted atomic medium can be obtained as [42] …”

Talbot effect of ring laser array realized by Gyrator canonical transformation

“…自 1836 年 H.F.Talbot [1] 报道了周期性物体的衍射自成像效应以来，对 Talbot 效应的研究和应用逐 步深入。尤其是分数 Talbot 效应的理论解释 [2] ，进一步拓宽了 Talbot 效应的应用范围，更加引起研究 人员对 Talbot 效应的重视。目前，Talbot 效应和分数 Talbot 效应已在光学图形处理 [3,4] 、光学精密测 量 [5] 、光信息存储 [6] 、原子光学 [7][8][9] 、阵列照明 [10,11] 等领域得到了广泛应用。随着半导体激光技术的不 断发展，由半导体激光器组成的周期性阵列其光场同样具有 Talbot 效应，值得人们研究。并根据分数 Talbot 效应 [12] ，人们开展了半导体激光阵列 Talbot 外腔锁相的研究 [13,14] 。通过激光阵列 Talbot 外腔锁 相技术，可以提高激光阵列互注入耦合效率 [15] ，实现激光低阶模式选择，有效改善大阵列半导体激 光器的远场光束质量，获得近衍射极限的相干激光输出 [16] 。由于锁相后的激光阵列具有高简并度和 相干性，亦可将其应用于量子测量技术，实现以高度相干的激光操纵玻色-爱因斯坦凝聚体(BEC) 形成原子密度光栅 [17,18] 。因此，激光阵列的 Talbot 效应在未来高功率、高光束质量半导体激光器以 及量子测量领域蕴藏着广阔的实用前景。 一维激光器阵列的 Talbot 效应是半导体激光阵列 Talbot 外腔锁相研究的一个重要方向 [19,20] ，然 而在实际应用中，一维激光阵列难以达到无限单元周期性排布，使得一维激光阵列无法产生理想的 Talbot 效应，即存在边缘效应。与一维激光阵列相比，环形激光阵列在极坐标系下具有角向无限周期 性单元结构，可以近似为无限单元的一维周期性阵列结构 [21] ，满足 Talbot 条件。 通常，人们采用笛卡尔坐标系下的分数傅里叶变换计周期性物体的 Talbot 效应 [22,23] 。然而这种 方法难以计算环形激光阵列的 Talbot 效应，本文在极坐标系下将环形激光阵列的 Gyrator 变换和菲涅 尔衍射相结合， 推导了环形激光阵列的 Talbot 效应， 获得了其 Talbot 自成像条件。 通过 FDTD Solutions…”

Talbot effect based on a Raman-induced grating

“…Another type of a lensless imaging scheme based on electromagnetically induced holographic imaging is proposed in [23]. In contrast to the EITE scheme [17], this one allows both the amplitude and phase information of the generated EIG to be imaged with the characteristic of the arbitrarily controllable image variation in size.…”