Genetic algorithm optimization for storing arbitrary multimode transverse images in thermal atomic vapor

Abstract

Storing multimode transverse images in atomic media is crucial in constructing large-scale quantum networks. A major obstacle of storing transverse images in the thermal atomic vapor is the distortion of the retrieved images caused by atomic diffusion. Here, we demonstrate the combination of genetic algorithm with the phase-shift lithography method to construct the optimal phase for an arbitrary transverse image that can diminish the effect of diffusion. Theoretical simulations and experimental results manifest that the retrieved images' resolution can be substantially improved when carrying the optimal phases. Our scheme is efficient and straightforward and can be extensively applied in storing complex transverse multimodes in diffusion media.

Angular dependence of spatial frequency modulation in diffusion media

“…The cell contains 8 Torr neon buffer gas and is heated to 60 • C, rendering a diffusion coefficient of D ≈ 25 cm 2 /s [29]. The adopted experimental setup (see Appendix A for details) is similar to that in our previous work [8]. Here the wavevector of the control beam is modulated while the probe's wavevector remains unchanged and they intersect at the center of the atomic cell.…”

“…[6,8], in which the authors increase the stored image's visibility by imposing π-phase shift between neighboring features of the image. However, rotating the wavevector offers greater convenience since there is no need to elaborately design and load the phase pattern to the image [6,8]. It is also worth noting that Eq.…”

“…Coherent manipulation of transverse multimode light fields, such as optical modes with representative transverse structures [1][2][3][4] or arbitrary optical images [5][6][7][8], via light-atom interaction is essential for the development of quantum optics and quantum information. External light or magnetic fields can modulate the optical response of the atoms, then change the absorption and dispersion of the optical field propagating through such media.…”

“…This is a defect that degrades the image's quality when it is manipulated with the slow and storage light techniques in the hot vapor cell. To date, the conventional approaches to solve these problems are mostly based on modulating the wavefront of the optical image [6][7][8]25]. For instance, loading an appropriate phase to the image according to the optical phase-shift lithography principle [6,8], storing the Fourier transform of the image [7], or encoding images into thermal light and adopting the correlation imaging technique [25] could all alleviate the influence of atomic diffusion on the quality of retrieved images.…”

“…To date, the conventional approaches to solve these problems are mostly based on modulating the wavefront of the optical image [6][7][8]25]. For instance, loading an appropriate phase to the image according to the optical phase-shift lithography principle [6,8], storing the Fourier transform of the image [7], or encoding images into thermal light and adopting the correlation imaging technique [25] could all alleviate the influence of atomic diffusion on the quality of retrieved images. Nevertheless, these methods need additional optical devices such as a spatial light modulator (SLM) for wavefront modulation, which limits the flexibility of their practical applications.…”