Re: laser optics design
- From: Jamie <jacarter3@xxxxxxxxxxxxx>
- Date: Wed, 25 Jul 2007 07:54:09 -0700
I am posting this again as it didn't appear to appear in the news
group...
The impact of the laser (coherent beam with a Gaussian amplitude
distribution possibly with higher order Hermite or Laguerre modes)
effects depends greatly upon the type of optics and the application.
General practice is to design the optical system using standard
optical design methods using a Gaussian pupil apodization that
represents the anticipated laser size. Generally I use a set of
wavelengths that include the laser wavelength but add two lines close
to and on either side of the laser wavelength to minimize dispersion
unless I know that the laser will give an exact the wavelength (or
wavelengths for multiple line lasers like Argon of Krypton plasma
lasers) due to a known energy band gap. Semiconductor lasers (laser
diodes) can give a range a wavelengths depending on doping variances
(in the fabrication process, wafer to wafer) and due to temperature
variation.
The optical system should perform as "diffraction limited'' for all
configurations of the optical design especially for "pre lens" scanner
systems. Post lens scanners where the scanner (galvanometer of
polygon, etc.) probably have only one configuration unless a variable
beam expander of focus shifting configuration set are employed. After
ensuring that the optical system is diffraction limited for both
design residuals and optical fabrication and alignment tolerance
residuals, the system should be assessed for its Gaussian beam
behavior.
Most modern optical design programs have a Gaussian beam analysis
feature nowadays. This feature will create a paraxial expansion about
the chief ray and perform an ABCD matrix type of calculation that
gives the spot size, beam curvature, waist size and waist location in
both axes and for every surface in the prescription. These results
should agree with your design intent if the system is designed
properly. Often some iteration may be needed between the geometrical
design and Gaussian analysis.
Two thing t note about laser system design and Gaussian beam
characteristics:
1] There are just to types optical systems, focal and not focal
(afocal). Afocal systems that are diffraction limited have Gaussian
beam characteristics that are identical to the geometrical
characteristics. The magnification and imaging of waist through the
afocal black box is identical to the geometrical magnification and
pupil imaging. For focusing systems, the focused laser waist will
deviate from the geometric focus and that gives he need for the
Gaussian analysis.
2] If the system is NOT diffraction limited, the Gaussian analysis is
meaningless. This is the single most frequent problem that beginners
have with designing laser systems.
I have more tips and tricks, but these must wait until I have more
time to give to writing them down.
Hope this helps.
James Carter
http://www.opticalconsulting.com
On Jul 25, 12:02 am, kan <kanikpalo...@xxxxxxxxx> wrote:
hello
I am a new fellow in this field.
Please help me out suggesting which software to use for designing
laser systems, or gaussian optics systems.
is there any good books which deal with the problems of gaussian
optics design?
Thanks
Kanik
.
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- laser optics design
- From: kan
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