Optical and thermal imaging of nanostructures with a scanning fluorescent particle as a probe. Near-field experiments : ESPCI, Paris, FranceLionel Aigouy, Benjamin Samson Samples : IEF, Orsay, France Gwénaelle Julié, Véronique Mathet TIMA, Grenoble, FranceBenoît Charlot LAAS, Toulouse, FranceChristian Bergaud LPS, Orsay, FranceRosella Latempa, Marco Aprili Fluorescent particles : ENSCP, Paris, FranceMichel Mortier

OUTLINE Introduction : fluorescent particle as a local sensor

OUTLINE Introduction : fluorescent particle as a local sensor A local optical sensor (evanescent fields) Local field around metallic nanoparticles

OUTLINE Introduction : fluorescent particle as a local sensor Local field around metallic nanoparticles Surface plasmons polaritons launched by apertures A local optical sensor (evanescent fields)

OUTLINE Introduction : fluorescent particle as a local sensor A local thermal sensor Hot zones in a polysilicon resistive stripe Local field around metallic nanoparticles Surface plasmons polaritons launched by apertures A local optical sensor (evanescent fields)

OUTLINE Introduction : fluorescent particle as a local sensor Hot zones in a polysilicon resistive stripe Heating of an aluminum track Local field around metallic nanoparticles Surface plasmons polaritons launched by apertures A local optical sensor (evanescent fields) A local thermal sensor

HOW DOES IT WORK ? PM Sample Electromagnetic field on the surface Microscope objective Filters Laser Map of the field distribution on the surface

HOW DOES IT WORK ? PM Electromagnetic field on the surface Microscope objective Filters Map of the total field distribution on the surface Simplicity Many dipoles randomly oriented Detection of the total electromagnetic field on the surface (Ex, Ey, Ez) Sample Laser APL, 83, 147 (2003)

HOW DOES IT WORK ? Simplicity PM Electromagnetic field on the surface Microscope objective Filters Many dipoles randomly oriented Detection of the total electromagnetic field on the surface (Ex, Ey, Ez) Er / Yb ions Robust : inorganic → no photobleaching Infrared excitation : emission and absorption lines well separated ( = 550nm) Non linear excitation : fluo  I 2 → Contrast enhanced Sample Laser ( =974nm) APL, 83, 147 (2003)

TIP FABRICATION Optical images : 16.5 x 11.7  m 2 Applied Optics, 43(19) 3829 (2004) Attachment of the particle

TIP FABRICATION Optical images : 16.5 x 11.7  m 2 Applied Optics, 43(19) 3829 (2004) Attachment of the particle 200nm size particle exc = 975 nm Lateral resolution : / 5

LOCAL OPTICAL FIELDS : NANOPARTICLES AFM Particle diameter : 250 nm Gold and latex particles on a surface

LOCAL OPTICAL FIELDS : NANOPARTICLES AFM Gold and latex particles on a surface Fluorescence Particle diameter : 250 nm

LOCAL OPTICAL FIELDS : NANOPARTICLES AFM Fluorescence is enhanced on gold particles Gold Latex JAP, (2005). Gold and latex particles on a surface Fluorescence Particle diameter : 250 nm

LOCAL OPTICAL FIELDS : NANOPARTICLES AFM Fluorescence is enhanced on gold particles Gold Latex JAP, (2005). Dark ring around the particle : interference between the incident and the scattered wave. Circular symmetry of the field distribution Gold and latex particles on a surface Fluorescence Map of the field distribution on the structure Particle diameter : 250 nm

LOCAL OPTICAL FIELDS : NANOSLIT APERTURES TM-polarized excitation 10,44µm SEM scan

LOCAL OPTICAL FIELDS : NANOSLIT APERTURES TM-polarized excitation scan d=10,44µm 10,44µm SEM

LOCAL OPTICAL FIELDS : NANOSLIT APERTURES TM-polarized excitation scan d=10,44µm Period = nm ± 2 nm spp / 2 = nm Good agreement with the SPP wavelength

OTHER APPLICATION : TEMPERATURE MEASUREMENTS Fluorescent particle Emission varies with temperature

OTHER APPLICATION : TEMPERATURE MEASUREMENTS Fluorescent particle Emission varies with temperature Tip Fluorescent particle Stripe Microelectronic device Laser beam

OTHER APPLICATION : TEMPERATURE MEASUREMENTS Fluorescent particle Emission varies with temperature Tip Microelectronic device T ° I Fluorescent particle Stripe If we know the temperature dependence of the fluorescence, then we can determine the temperature Laser beam

OTHER APPLICATION : TEMPERATURE MEASUREMENTS Highly localized sensor Improvement of the lateral resolution Pollock & Hammiche, J. Phys. D 34, R23 (2001)

OTHER APPLICATION : TEMPERATURE MEASUREMENTS Improvement of the lateral resolution Pollock & Hammiche, J. Phys. D 34, R23 (2001) Low parasitic heating by convection through the air Highly localized sensor

HOW CAN WE DEDUCE THE TEMPERATURE ? Er / Yb ions PL spectrum of Er / Yb doped particles

HOW CAN WE DEDUCE THE TEMPERATURE ? 4 F 7/2 2 H 11/2 4 S 3/2 4 I 15/2 (550 nm)(527 nm) (980 nm) Er / Yb ions PL spectrum of Er / Yb doped particles

EXPERIMENTAL SET-UP Microelectronic circuit Oscillating tip Topography Scanning stage Tapping mode (f=6kHz, amplitude=10nm)

EXPERIMENTAL SET-UP Microelectronic circuit Oscillating tip Topography Scanning stage Tapping mode (f=6kHz, amplitude=10nm) F=620Hz Laser beam (980nm)

EXPERIMENTAL SET-UP Microelectronic circuit Oscillating tip Topography Scanning stage Tapping mode (f=6kHz, amplitude=10nm) Laser beam (980nm) F=620Hz Beam splitter

EXPERIMENTAL SET-UP Microelectronic circuit Oscillating tip Topography Scanning stage Tapping mode (f=6kHz, amplitude=10nm) Laser beam (980nm) F=620Hz 520nm Filter PMT Lock-in Optical image 1 Beam splitter

EXPERIMENTAL SET-UP Microelectronic circuit Oscillating tip Topography Scanning stage Laser beam (980nm) F=620Hz 550nm 520nm Filter PMT Lock-in Optical image 2 Tapping mode (f=6kHz, amplitude=10nm) Optical image 1 Beam splitter PMT

DOES THAT WORK ? Collaboration : B. Charlot (TIMA, Grenoble), G. Tessier (ESPCI, Paris) Polysilicon resistor stripe (covered with SiO 2 and Si 3 N 4 layers) Topography Yellow optical image (550nm) Green optical image (520nm) Microelectronic device :

DOES THAT WORK ? First experiment : no current circulating in the resistor Yellow fluorescence image (550nm) Green fluorescence image (520nm) Topography Scan size : 45µm x 60µm

DOES THAT WORK ? First experiment : no current circulating in the resistor Yellow fluorescence image (550nm) Green fluorescence image (520nm) Topography Scan size : 45µm x 60µm Optical contrast visible between different zones Reference image Uniform temperature (room temperature) I = 0 mA

DOES THAT WORK ? Second experiment : a current circulates in the resistor Uniform temperature (room temperature) Optical contrast visible between different zones Reference image I = 50 mA I = 0 mA APL, 87, (2005). Hot spots

CONCLUSION Scanning near-field fluorescent probes have really interesting imaging capabilities ! Future : - Reduce the size of the fluorescent particle : to get a better resolution - Many studies : plasmonics and thermics Nano-optics : evanescent fields (localized, surface plasmons polaritons) Nano-thermics : heating in stripes, failure analysis, … UNIVERSAL DETECTOR ! Acknowledgments : Philippe Lalanne (Institute of Optics, Orsay, and US Dax supporter)