Low-Light-Level Cross-Phase Modulation with Double Slow Light Pulses

Abstract

We report on the first experimental demonstration of low-light-level cross-phase modulation (XPM) with double slow light pulses based on the double electromagnetically induced transparency (EIT) in cold cesium atoms. The double EIT is implemented with two control fields and two weak fields that drive populations prepared in the two doubly spin-polarized states. Group velocity matching can be obtained by tuning the intensity of either of the control fields. The XPM is based on the asymmetric M-type five-level system formed by the two sets of EIT. Enhancement in the XPM by group velocity matching is observed. Our work advances studies of low-light-level nonlinear optics based on double slow light pulses.

Experimental demonstration of spinor slow light

“…The slow and stationary light, forming due to the electromagnetically induced transparency (EIT) effect [43][44][45] , greatly enhance the light-matter interaction and enable nonlinear optical processes to achieve significant efficiency even at singlephoton level [26][27][28][29][30][31][32][33][34][35] . The storage of light using the dynamic EIT scheme transfers quantum states between photons and atoms, serving as quantum memory for photons [38][39][40][41][42] .…”

“…O ver the last decade there have been significant advances in studying the slow [1][2][3][4][5][6][7][8][9][10][11][12] , stored [13][14][15][16][17][18][19][20][21] and stationary [22][23][24][25] light stimulated by applications to low-light-level nonlinear optics [26][27][28][29][30][31][32][33][34][35] and quantum information manipulation [36][37][38][39][40][41][42] . The slow and stationary light, forming due to the electromagnetically induced transparency (EIT) effect [43][44][45] , greatly enhance the light-matter interaction and enable nonlinear optical processes to achieve significant efficiency even at singlephoton level [26][27][28]…”

Slow, Stored and Stationary Light

“…Several ideas have been put forward here to exploit the properties of slow light for implementing strong interactions. For example, the possibility offered by EIT to operate close to atomic resonances without suffering from absorption can be exploited to enhance nonlinear optical processes in atomic media [21,[38][39][40][41][42][43][44]. Another very promising direction is to combine EIT with the so-called Rydberg atoms.…”

Large Phase-by-Phase Modulations in Atomic Interfaces

“…Electromagnetically induced transparency, e.g., is commonly used in trapped atomic samples to enhance the weak Kerr effect responsible for the photonphoton interaction, namely, through a significant reduction of the photon's propagation speed. Within this context, multilevel atom configurations driven to attain large crossphase-modulation effects have been extensively studied [12][13][14][15][16] and over the years various demonstrations [17][18][19][20] of phase shifts, which may even reach the size of a radian [21][22][23], have been carried out yet at the price of fairly large light intensities. Conversely, this seems to confirm early predictions that large shifts through enhancement of Kerr nonlinearities at low-light levels or even down to the singlephoton level [24,25] are unlikely.…”