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Re: Focus field calculation in High Numerical aperture systems.
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Phil Hobbs
Apr 29, 2013, 7:57:00 PM4/29/13
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On 4/29/2013 12:02 PM, mga...@gmail.com wrote:
> Hi all,
>
> The classical paper by Richard and wolf is used a benchmark for calculating the focus field distribution in high NA systems. Other authors like Mansuripur used a different approach to calculate the field in the focus mainly dealing with how to ease the computational efforts.
> Do you think that it is possible to formulate a general benchmark which can be used as reference to check the accuracy of the above methods ?(i.e formulating an analytical or any other general solution of a vector diffraction problem used to check the accuracy of the Debye-Wolf integral solution and the Mansuripur's Fourier implementation)
>
Maxwell's equations are linear, so calculating the fields near a focus
is not a conceptually difficult exercise. (There may be analytical
difficulties, of course.)
A lot of the subtleties of high-NA beams has to do with the initial
conditions assumed, e.g. whether to use the Debye approximation for the
angular spectrum, whether to put in the inverse of the cosine obliquity
factor to account for the bunching of rays near the rim, and so on.
AFAIK it's still the case that nobody knows what a lens does in any sort
of exhaustive detail.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510 USA
+1 845 480 2058
hobbs at electrooptical dot net
http://electrooptical.net
> Hi all,
>
> The classical paper by Richard and wolf is used a benchmark for calculating the focus field distribution in high NA systems. Other authors like Mansuripur used a different approach to calculate the field in the focus mainly dealing with how to ease the computational efforts.
> Do you think that it is possible to formulate a general benchmark which can be used as reference to check the accuracy of the above methods ?(i.e formulating an analytical or any other general solution of a vector diffraction problem used to check the accuracy of the Debye-Wolf integral solution and the Mansuripur's Fourier implementation)
>
Maxwell's equations are linear, so calculating the fields near a focus
is not a conceptually difficult exercise. (There may be analytical
difficulties, of course.)
A lot of the subtleties of high-NA beams has to do with the initial
conditions assumed, e.g. whether to use the Debye approximation for the
angular spectrum, whether to put in the inverse of the cosine obliquity
factor to account for the bunching of rays near the rim, and so on.
AFAIK it's still the case that nobody knows what a lens does in any sort
of exhaustive detail.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510 USA
+1 845 480 2058
hobbs at electrooptical dot net
http://electrooptical.net
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