13-12-2010, 10:50 PM
SURFACE PLASMON RESONANCE NANOLASERS
HARIPRASAD.K
S7B
HARIPRASAD.K
S7B
OVERVIEW
INTRODUCTION
WHAT IS SPR?
SURFACE PLASMON SPECTROSCOPY
LASER BASICS
SPASER
THEORY OF SPASER
COMPARING LASER & SPASER
DEMONSTRATION OF SPASER
ADVANTAGES
APPLICATIONS
CONCLUSION & FUTURE SCOPE
REFERENCES
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Introduction
Surface plasmons
oscillations of electrons
found in boundary b/w metal & dielectric
intensity max across the surface
How to excite a SP?
using p-polarised light
Otto configuration Kretschmann configuration
Surface plasmon spectroscopy
To measure : - thickness changes,
- density fluctuation
- molecular adsorption
laser basics
High conc. of energy & monochromatic light
Stimulated emission of coherent photons
Electrons generate photos
Laser basics
Absorption
Spontaneous & Stimulated emission
Optical pumping
Optical resonators
Distance between mirrors is a main factor
spaser
What is a spaser?
Quantum generator of surface plasmon
Nanoplasmonic counterpart of laser
Temporarily coherent near atomic intensity field
Ultrafast
Theory of spaser
Based on two level emitters- quantum dots
Energy transfer is radiationless
Resonant nanosystem acts as a laser cavity
Theory of spaser
Comparing laser and spaser
Laser – photons. Spasers – surface plasmons
Resonant cavity replaced by nanoparticle
Surface plasmons have spin just as photons
Energy source(gain medium) excited externally
Both undergo stimulated emission
Laser-half the wavelength
Demonstration of spaser
Spaser in gold nanoparticle surrounded by silica shell impregnated with green dye.( By Mikhail Noginov)
Demonstration of spaser
Spaser containing cadmium sulphide on top of silver substrate separated by magnesium fluoride (By Zhang & Oulton)
Advantages
SP can confine within tighter spots
Ultrafast than MOSFETs
Heating effect localized on nanocsale
Highly resistant to temp. & adverse envt.
Applications of spasers
Nanoscale lithography, microscopy
Nanoscale optical probing
Optical computing
Analyzing individual molecules
Magnetic data storage enhancement
Conclusion & Future scope
Spaser driven by an electrical source
Design spaser analogous to MOSFET transistor
REFERENCES
M.I.Stockman and D.J.Bergman, “Quantum nanoplasmonics: Surface Plasmon Amplification by Stimulated Emission of Radiation (SPASER),” in Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference,paper QThPDA10.
M. I. Stockman, Spaser as Nanoscale Generator and Ultrafast Amplifier, J.Opt. 12, 024004-1-13 (2010)
“The Spaser Nanolaser”, IEEE Spectrum, October 2009
M. I. Stockman, Spasers Explained, Nature Photonics 2, 327-329 (2008)
http://www.wikipedia.com