Evanescent-wave holographic recording in nano-scale material: Optical and holographic properties of nano-sized As2S3 films - PowerPoint PPT Presentation

Loading...

PPT – Evanescent-wave holographic recording in nano-scale material: Optical and holographic properties of nano-sized As2S3 films PowerPoint presentation | free to download - id: 4b93e9-ZDIyO



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Evanescent-wave holographic recording in nano-scale material: Optical and holographic properties of nano-sized As2S3 films

Description:

Experimental Theoretical background Theoretical background Sample preparation The nano-sized As2S3 films are prepared in ... evaporation of high purity As2S3 ... thin ... – PowerPoint PPT presentation

Number of Views:131
Avg rating:3.0/5.0
Slides: 17
Provided by: Kostad9
Learn more at: http://www.physik.tu-berlin.de
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Evanescent-wave holographic recording in nano-scale material: Optical and holographic properties of nano-sized As2S3 films


1
Evanescent-wave holographic recording in
nano-scale materialOptical and holographic
properties of nano-sized As2S3 films
Central Laboratory of Optical Storage and
Processing of Information
S. Sainov, J. Dikova
Central Laboratory of Photoprocesses, Bulgarian
Academy of Sciences
2
Experimental
3
(No Transcript)
4
Theoretical background
Evanescent -evanescent waves interference
ao is plane wave amplitude ?i is the incidence
angle zo is the penetration depth ?c is a TIR
critical angle ?o is the wavelength in the
air K is grating vector ? is grating period
5
Theoretical background
Plane-evanescent waves interference
6
Sample preparation
  • The nano-sized As2S3 films are prepared in the
    Central Laboratory of Photoprocesses, Bulgarian
    Academy of Sciences. The experimental samples are
    obtained by thermal evaporation of high purity
    As2S3 in a standard vacuum unit maintaining
    residual pressure in the order of 5x10-4 Pa. A
    resistively heated Ta crucible with a special
    design is used as an evaporation source. The
    deposition rate is 0.1 nm/s, which is
    sufficiently low for the films thickness control
    with a preliminary calibrated quartz crystal
    monitor.

7
Optical Properties
Spectral dependences of refractive index with the
corresponding errors as vertical lines for DE
dependence with indicated thicknesses. The inset
shows the thickness dependences of n at ? 488
nm and the voids volume.
8
Optical Properties
Spectral dependences of absorption index with the
corresponding errors as vertical lines for
a-As2S3 thin film with indicated thicknesses. The
inset shows the plot (?E)1/2 vs. (E) and linear
fit to (?E) 0 for determination of Eg.
9
Holographic recording
Experimental set-up L-laser Mi mirror
BS-beam splitter S-shutter F- As2S3 film P-
prism RF-red filter PM-power meter
10
Diffraction efficiency dependence on the exposure
at different gratings periods (spatial
frequencies) and film thicknesses
11
Diffraction efficiency dependence on the exposure
at different gratings periods (spatial
frequencies) and film thicknesses
12
Diffraction efficiency dependence on the exposure
at different gratings periods (spatial
frequencies) and film thicknesses
13
Normalized diffraction efficiency dependence on
the spatial frequency
14
10nm
15nm
15
Conclusions
  • We have demonstrated that the holographic
    recording in 29, 15 and 10nm thick chalcogenide
    As2S3 film could be achieved using evanescent
    wave interference technique. The grating period
    range is 3.2 0.37?m (spatial frequency range
    310-2700mm-1). The experimentally observed
    Bragg-type diffraction efficiency features are
    similar to the thick grating recording with
    homogeneous waves. We believe that evanescent -
    wave holography will become a useful nano-tool
    alongside with the scanning tunneling techniques
    for studying the structures and phenomena at a
    nanometer scale. This includes holographic
    grating method for interferometric measurements,
    diffusion investigations, laser lithography, etc.

16
Thank you!
About PowerShow.com