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Micro-diffractive nanostructures for cold-atom manipulation (and other interesting stuff) Groupe optique atomique et applications Micro-diffractive nanostructures for cold-atom manipulation (and other interesting stuff) Groupe optique atomique et applications aux nanostructures Université Paul Sabatier—CNRS Toulouse, France FRISNO-8 Ein-Bokek, Israel February 20 -25, 2005 http: //www. nanocold. cict. fr http: //www. fastnet. fr

The basic idea cold atoms output optical field incoming laser light structured surface The basic idea cold atoms output optical field incoming laser light structured surface

Subwavelength Structures FIB Fabrication Subwavelength Structures FIB Fabrication

Arrays of Holes in Metal Films Light transmission spectrum Is this evidence of surface Arrays of Holes in Metal Films Light transmission spectrum Is this evidence of surface plasmons?

Decorated Slits and Holes in Subwavelength Ag Membranes Decorated Slits and Holes in Subwavelength Ag Membranes

Light transmission through a slit flanked by periodic grooves detected far-field transmission calculated profile Light transmission through a slit flanked by periodic grooves detected far-field transmission calculated profile Garcia-Vidal, et al. , Appl. Phys. Lett. 83, 4500 (2003)

Measuring the transmission profile– atomic fluorescence mapping of the field intensity Measuring the transmission profile– atomic fluorescence mapping of the field intensity

Relation between atomic fluorescence and field intensity excited atoms field intensity Relation between atomic fluorescence and field intensity excited atoms field intensity

100 nm slit flanked by 10 grooves each side calculated measured 100 nm slit flanked by 10 grooves each side calculated measured

How does the slit/groove structure produce the observed field distributions? How does the slit/groove structure produce the observed field distributions?

Composite Diffracted Evanescent Wave Lezec and Thio Optics Express, 12 3629 (2004) Composite Diffracted Evanescent Wave Lezec and Thio Optics Express, 12 3629 (2004)

Composite Evanescent Wave-I Consider diffraction at a slit of width d. The field along Composite Evanescent Wave-I Consider diffraction at a slit of width d. The field along x is given by: - = Kowarz, Appl. Optics. 34, 3055 (1995)

Composite Evanescent Wave-II x/d The phase shift of pi/2 is a signature of the Composite Evanescent Wave-II x/d The phase shift of pi/2 is a signature of the CEW.

CEWs launched on the surface output optical field incoming laser light structured surface CEWs launched on the surface output optical field incoming laser light structured surface

A pi/2 phase shift between the directly transmitted wave and the CEW 50 nm A pi/2 phase shift between the directly transmitted wave and the CEW 50 nm We can “jog” the structures to compensate for the phase shift variable jog 100 nm incoming light 830 nm

Jogged and unjogged slit structures unjogged inward by ¼ period Jogged and unjogged slit structures unjogged inward by ¼ period

Distribution and number of grooves controls the output optical field We can produce a Distribution and number of grooves controls the output optical field We can produce a “phased array” with constructive interference in the forward direction. The result is a forward “flame” far-field intensity, no phase shift far-field intensity, with phase shift .

Flame divergence vs. grooves—expmt. and model for unjogged grooves calculation 10 grooves 30 grooves Flame divergence vs. grooves—expmt. and model for unjogged grooves calculation 10 grooves 30 grooves

Flame intensity vs. groove number for jogged and unjogged grooves unjogged Flame intensity vs. groove number for jogged and unjogged grooves unjogged

Flame angular distributions f d outgoing light incoming light coupling microscope objective CCD Flame angular distributions f d outgoing light incoming light coupling microscope objective CCD

Angular distribution of light vs. groove-slit spacing (in units of period N) for 5 Angular distribution of light vs. groove-slit spacing (in units of period N) for 5 grooves

Intensity angular distribution—jogged grooves output side, 3 selected distances CDEW model measured Intensity angular distribution—jogged grooves output side, 3 selected distances CDEW model measured

Intensity angular distribution—output side, unjogged red, jogged black CDEW model: Phase shift: r. CDEW=p/2 Intensity angular distribution—output side, unjogged red, jogged black CDEW model: Phase shift: r. CDEW=p/2 Index: n. CDEW=850/830=1. 024 Relative field amplitude a/x=2/x

Angular lobe spacing unjogged CDEW model Experiment Angular lobe spacing unjogged CDEW model Experiment

Next step: mirror MOT to get cold atoms close to surface Next step: mirror MOT to get cold atoms close to surface

Next step: mirror MOT with the optical funnel generated by a planar nanostructured phased Next step: mirror MOT with the optical funnel generated by a planar nanostructured phased array Mirror MOT atom trajectories optical funnel phased array structure plane wave excitation

Toward integrated structures: cold atom sources and transport on a chip Toward integrated structures: cold atom sources and transport on a chip

Diffraction and confinement Champs proches optiques : confinement sub-longueur d’onde de la lumière. Interaction Diffraction and confinement Champs proches optiques : confinement sub-longueur d’onde de la lumière. Interaction atomes neutres-lumière interaction dipolaire optique atomique cohérente : diffraction nanolithographie

Coupled resonant rings: symmetric/antisymmetric modes Coupled resonant rings: symmetric/antisymmetric modes

Funnel effect: optical potential above the rings Funnel effect: optical potential above the rings

Réseau à onde évanescente stationnaire -1 +1 * Proposé et réalisé : Théorie : Réseau à onde évanescente stationnaire -1 +1 * Proposé et réalisé : Théorie : Expérience : J. V. Hajnal & G. I Opat (1989). R. Deutschmann (1993), C. Henkel (1994). Villetaneuse (1996), Orsay (1998).

Autre approche : potentiel nanostructuré Réseau à onde évanescente nanostructurée : période orientation motif Autre approche : potentiel nanostructuré Réseau à onde évanescente nanostructurée : période orientation motif D. van Labeke & D. Barchiesi A. Roberts & J. E. Murphy (1996) Diffraction de l’onde évanescente :

Periodicity controllable through angle of optical coupling-1 50 nm above surface 250 nm above Periodicity controllable through angle of optical coupling-1 50 nm above surface 250 nm above surface

Periodicity controllable through angle of optical coupling-2 50 nm above surface 250 nm above Periodicity controllable through angle of optical coupling-2 50 nm above surface 250 nm above surface

Experimental parameters MOT ld. B=5 nm Lx=Ly=250 nm qdiff=20 mrad e=100 nm j=40° q=55° Experimental parameters MOT ld. B=5 nm Lx=Ly=250 nm qdiff=20 mrad e=100 nm j=40° q=55° n=2. 1 (Ti. O 2) zr=250 nm

Tales from the future—nanophotonics, addressable atom manipulation with optical arrays Tales from the future—nanophotonics, addressable atom manipulation with optical arrays

E=10 V/200 nm Ba. Ti. O 3: n 0=2. 4 E= 0. 5 108 E=10 V/200 nm Ba. Ti. O 3: n 0=2. 4 E= 0. 5 108 V/m r 42=1300 pm/V Dn=0. 45 (20%)

Electro-Optic Beaming Control with variable index of refraction Quartz Ag V Ba. Ti. O Electro-Optic Beaming Control with variable index of refraction Quartz Ag V Ba. Ti. O 3 Sr. Ru 4 O 3 Variable Depth Focusing

Electro-Optic Beaming Control Quartz Ag V Ba. Ti. O 3 Sr. Ru 4 O Electro-Optic Beaming Control Quartz Ag V Ba. Ti. O 3 Sr. Ru 4 O 3 Change n from 0. 8 to 1. 2 Steering

Future: arrays of optical traps loaded with one or more atoms 125µm R. Dumke, Future: arrays of optical traps loaded with one or more atoms 125µm R. Dumke, et al. PRL 89, 097903 (2002)

Summary—evolution of conception Yesterday: Tomorrow: 10 µm Summary—evolution of conception Yesterday: Tomorrow: 10 µm

The Group Guillaume Gay Olivier Alloschery Bruno Viaris Colm O’Dwyer Renaud Mathevet Gaetan Leveque The Group Guillaume Gay Olivier Alloschery Bruno Viaris Colm O’Dwyer Renaud Mathevet Gaetan Leveque