Re: Question on detection depth of Fourier Domain OCT

From: Barry (barry_in_boston_at_hotmail.com)
Date: 09/15/04 

Date: 15 Sep 2004 09:18:08 -0700

jmgong74@tom.com (Jim) wrote in message news:<78034be6.0409141808.3b2690e3@posting.google.com>...
> It is widely accepted that, in Fourrier domain OCT, depth information
> can be obtained without position scan of the reference mirror. They
> can be calculated from the Fourier transform of the spectral response
> of the FDOCT.
>
> However, it seems that the theory is based on an assumption that light
> is back-reflected or back-scattered by the sample. If the light is
> scattered by the sample to all directions (it is true for real
> application), is the theory still valid? Or in other words, can we use
> Fourier transform to obtain depth information?
>
> Thank you!

I don't really understand your question, so maybe I should not answer
it. But I'll try it anyway.

The answer is yes.

The light that is incident turbid biological tissue, is scattered by
the sample in all directions. There is some back scattering, there is
some forward scattering, and there is also some multiple scattering.
So, although quite a bit of light is lost due to scattering, the
little amount of light that actually back scatters directly towards
the detector and interferes with reference arm power can generate a
nice signal. This so called "cross-spectral density function" can be
transformed into a depth profile by a Fourier transform. It is that
easy. If you want to see some recent examples of Fourier-domain OCT
(also know as Spectral-domain OCT) take a look at:

http://www.opticsexpress.org/abstract.cfm?URI=OPEX-12-11-2435 (MGH
group)

http://www.opticsexpress.org/abstract.cfm?URI=OPEX-12-11-2404 (MIT
group)

http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-8-889 (Vienna
group)

http://www.opticsexpress.org/abstract.cfm?URI=OPEX-12-3-367 (MGH
group)

Sincerely,

Barry Cense (MGH group)

Relevant Pages

  • Question on detection depth of Fourier Domain OCT
    ... It is widely accepted that, in Fourrier domain OCT, depth information ... can be obtained without position scan of the reference mirror. ... can be calculted from the Fourier transform of the spectral response ...
    (sci.optics)
  • Question on detection depth of Fourier Domain OCT
    ... It is widely accepted that, in Fourrier domain OCT, depth information ... can be obtained without position scan of the reference mirror. ... can be calculted from the Fourier transform of the spectral response ...
    (sci.optics)
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