Optical and thermal imaging of nanostructures with a scanning fluorescent particle as a probe

Optical and thermal imaging of nanostructures with a scanning fluorescent particle as a probe.

Near-field experiments :

ESPCI, Paris, France Lionel Aigouy, Benjamin Samson

Samples :

IEF, Orsay, France Gwénaelle Julié, Véronique MathetTIMA, Grenoble, France Benoît CharlotLAAS, Toulouse, France Christian BergaudLPS, Orsay, France Rosella Latempa, Marco Aprili

Fluorescent particles :

ENSCP, Paris, France Michel 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

Microscopeobjective

Filters

Laser

Map of the field distribution on the

surface

HOW DOES IT WORK ? PM

Electromagnetic field on the surface

Microscopeobjective

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

Microscopeobjective

FiltersMany dipoles randomly oriented

Detection of the total electromagnetic field on the surface (Ex, Ey, Ez)

Er / Yb ionsRobust : inorganic → no photobleaching

Infrared excitation :emission and absorption lines well separated

(= 550nm)

Non linear excitation :fluo I2 → Contrast enhanced

Sample

Laser (=974nm)

APL, 83, 147 (2003)

TIP FABRICATION

Optical images : 16.5 x 11.7 m2

Applied Optics, 43(19) 3829 (2004)

Attachment of the particle

TIP FABRICATION

Optical images : 16.5 x 11.7 m2

Applied Optics, 43(19) 3829 (2004)

Attachment of the particle

200nm size particle exc = 975 nmLateral resolution : / 5

LOCAL OPTICAL FIELDS : NANOPARTICLES

AFM

Particle diameter : 250 nm

Gold and latex particles on a surface

LOCAL OPTICAL FIELDS : NANOPARTICLES

AFMGold and latex particles on a surface

Fluorescence

Particle diameter : 250 nm

LOCAL OPTICAL FIELDS : NANOPARTICLES

AFM

Fluorescence is enhanced on gold particles

Gold

LatexLatex

JAP, 97 104322 (2005).

Gold and latex particles on a surfaceFluorescence

Particle diameter : 250 nm

LOCAL OPTICAL FIELDS : NANOPARTICLES

AFM

Fluorescence is enhanced on gold particles

Gold

LatexLatex

JAP, 97 104322 (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 surfaceFluorescence

Map of the field distribution on the structure

Particle diameter : 250 nm

LOCAL OPTICAL FIELDS : NANOSLIT APERTURES

TM-polarized excitation

10,44µmSEM

scan

LOCAL OPTICAL FIELDS : NANOSLIT APERTURES

TM-polarized excitation

scand=10,44µm

10,44µmSEM

LOCAL OPTICAL FIELDS : NANOSLIT APERTURES

TM-polarized excitation

scand=10,44µm

Period = 480.5 nm ± 2 nm

spp / 2 = 481.6 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 particleStripe

Microelectronic device

Laser beam

OTHER APPLICATION : TEMPERATURE MEASUREMENTS

Fluorescent particle

Emission varies with temperature

Tip

Microelectronic device

T °

I

Fluorescent particleStripe

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 ionsPL spectrum of Er / Yb doped particles

HOW CAN WE DEDUCE THE TEMPERATURE ?

4F7/22H11/24S3/2

4I15/2

(550 nm)(527 nm)

(980 nm)

(980 nm)

Er / Yb ionsPL spectrum of Er / Yb doped particles

).

exp(Tk

E

I

I

yellow

green

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

spli

tter

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

spli

tter

EXPERIMENTAL SET-UP

Microelectronic circuit

Oscillating tip

Topography

Scanning stage

Laser beam

(980nm)

F=620Hz

550nm

520nm

Filter

Filter

PMT

Lock-in

Lock-in

Optical image 2

Tapping mode (f=6kHz, amplitude=10nm)

Optical image 1

Beam

spli

tter

PMT

DOES THAT WORK ? Collaboration : B. Charlot (TIMA, Grenoble), G. Tessier (ESPCI, Paris)

Polysilicon resistor stripe

(covered with SiO2 and Si3N4 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, 184105 (2005).

Hot spots

CONCLUSIONScanning 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)