View Full Version : Optics Researchers See the Light
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\nLehigh\'s Jean Toulouse and Iavor Veltchev are studying a phenomenon that few\nscientists in the world have been able to achieve.\n\nTwo physicists at Lehigh have produced a rainbow of visible and invisible\ncolors by focusing laser light in a specially designed optical fiber that\nconfines light in a glass core whose diameter is 40 times smaller than that\nof a human hair.\n\nFull story: http://www.physorg.com/news110.html\n\nThis is a very interesting phenomenon called "supercontinuum generation in\nnonlinear fibers", which is very difficult to achieve!\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that few
scientists in the world have been able to achieve.
Two physicists at Lehigh have produced a rainbow of visible and invisible
colors by focusing laser light in a specially designed optical fiber that
confines light in a glass core whose diameter is 40 times smaller than that
of a human hair.
Full story: http://www.physorg.com/news110.html
This is a very interesting phenomenon called "supercontinuum generation in
nonlinear fibers", which is very difficult to achieve!
AES/newspost
May26-04, 12:43 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n> Full story: http://www.physorg.com/news110.html\n>\n> This is a very interesting phenomenon called "supercontinuum generation in\n> nonlinear fibers", which is very difficult to achieve!\n>\n\nIndeed very interesting -- and technologically *very* important as well\n-- but not all that difficult to achieve actually, now that people have\nrealized it can be done. Also the Lehigh group are by no means the\nfirst people to demonstrate it; it\'s been in wide use and extensively\nexploited in numerous other laboratories for some time.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Full story: http://www.physorg.com/news110.html
>
> This is a very interesting phenomenon called "supercontinuum generation in
> nonlinear fibers", which is very difficult to achieve!
>
Indeed very interesting -- and technologically *very* important as well
-- but not all that difficult to achieve actually, now that people have
realized it can be done. Also the Lehigh group are by no means the
first people to demonstrate it; it's been in wide use and extensively
exploited in numerous other laboratories for some time.
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\nWhy is it so important technologically?\n\nPosted via http://forum.physorg.com\n\n"AES/newspost" <siegman@stanford.edu> wrote in message\nnews:siegman-DEEB98.10244726052004@news.stanford.edu...\n>\n>\n > > Full story: http://www.physorg.com/news110.html\n> >\n> > This is a very interesting phenomenon called "supercontinuum generation\nin\n> > nonlinear fibers", which is very difficult to achieve!\n> >\n>\n> Indeed very interesting -- and technologically *very* important as well\n> -- but not all that difficult to achieve actually, now that people have\n> realized it can be done. Also the Lehigh group are by no means the\n> first people to demonstrate it; it\'s been in wide use and extensively\n> exploited in numerous other laboratories for some time.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Why is it so important technologically?
Posted via http://forum.physorg.com
"AES/newspost" <siegman@stanford.edu> wrote in message
news:siegman-DEEB98.10244726052004@news.stanford.edu...
>
>
> > Full story: http://www.physorg.com/news110.html
> >
> > This is a very interesting phenomenon called "supercontinuum generation
in
> > nonlinear fibers", which is very difficult to achieve!
> >
>
> Indeed very interesting -- and technologically *very* important as well
> -- but not all that difficult to achieve actually, now that people have
> realized it can be done. Also the Lehigh group are by no means the
> first people to demonstrate it; it's been in wide use and extensively
> exploited in numerous other laboratories for some time.
J.C. Chastang
May27-04, 03:15 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n> Lehigh\'s Jean Toulouse and Iavor Veltchev are studying a phenomenon that\nfew\n> scientists in the world have been able to achieve.\n>\n> Two physicists at Lehigh have produced a rainbow of visible and invisible\n> colors by focusing laser light in a specially designed optical fiber that\n> confines light in a glass core whose diameter is 40 times smaller than\nthat\n> of a human hair.\n>\n> Full story: http://www.physorg.com/news110.html\n>\n> This is a very interesting phenomenon called "supercontinuum generation in\n> nonlinear fibers", which is very difficult to achieve!\n\nVery interesting but what kind of physics organization(s) use(s) the\n"diameter of a human hair" as a unit of length?\n\nWay down one is told:\n\n*A micron is one one-millionth of a meter; 2.5 microns is roughly\none-fourtieth [sic] the thickness of a typical human hair*\n\nI know it\'s only a press release, but it\'s fairly technical...\n\nThe human hair is the micro-unit, the macro-unit is the football field\n(interchangeably for length or area).\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that
few
> scientists in the world have been able to achieve.
>
> Two physicists at Lehigh have produced a rainbow of visible and invisible
> colors by focusing laser light in a specially designed optical fiber that
> confines light in a glass core whose diameter is 40 times smaller than
that
> of a human hair.
>
> Full story: http://www.physorg.com/news110.html
>
> This is a very interesting phenomenon called "supercontinuum generation in
> nonlinear fibers", which is very difficult to achieve!
Very interesting but what kind of physics organization(s) use(s) the
"diameter of a human hair" as a unit of length?
Way down one is told:
*A micron is one one-millionth of a meter; 2.5 microns is roughly
one-fourtieth [sic] the thickness of a typical human hair*
I know it's only a press release, but it's fairly technical...
The human hair is the micro-unit, the macro-unit is the football field
(interchangeably for length or area).
AES/newspost
May27-04, 03:15 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n> > > This is a very interesting phenomenon called "supercontinuum generation\n> in nonlinear fibers", which is very difficult to achieve!\n\n> > Indeed very interesting -- and technologically *very* important as well\n> > -- but not all that difficult to achieve actually, now that people have\n> > realized it can be done. Also the Lehigh group are by no means the\n> > first people to demonstrate it; it\'s been in wide use and extensively\n> > exploited in numerous other laboratories for some time.\n\n> Why is it so important technologically?\n\nIf the white light continuum is generated by a train of fs pulses (the\nusual situation), it\'s actually not a continuum but a dense "comb" of a\nhundred thousand or more optical frequency sidebands spaced apart by\nexactly the (precisely defined and readily measured) repetition\nfrequency of the pulses (which is typically in the middle\nradio-frequency range).\n\nTurns out that in practice and without too much difficulty this\nrepetition frequency and hence the sideband spacing can be extremely\nstable and jitter-free, giving you a precisely spaced set of optical\nreference frequencies extending across an octave or more in the visible\nand IR region.\n\nWith a little further trickery, sophisticated but again with reach of\navailable laser technology, one can adjust the exact positioning of this\ncomb so that not only are the spacings all equal, but each spectral line\nis actually at an *exact* harmonic multiple of the repetition frequency,\nso that the comb in essence extends all the way down to zero frequency.\n\nUsing standard techniques other highly stable cw or tunable lasers can\nthen be phase-locked to any of the individual optical comb lines -- and\nnow you have an optical clock or wavelength standard that\'s an exact\nknown harmonic multiple of a radio-frequency clock or time standard, or\nvice versa. Opens a new era in ultra-super-precision measurements of\nall kinds, for practical and basic scientific applications..\n\nThe whole subject beautifully reviewed in Ted Hansch\'s superb plenary\ntalk at CLEO/IQEC a week or so ago.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>This is a very interesting phenomenon called "supercontinuum generation
> in nonlinear fibers", which is very difficult to achieve!
> > Indeed very interesting -- and technologically *very* important as well
> > -- but not all that difficult to achieve actually, now that people have
> > realized it can be done. Also the Lehigh group are by no means the
> > first people to demonstrate it; it's been in wide use and extensively
> > exploited in numerous other laboratories for some time.
> Why is it so important technologically?
If the white light continuum is generated by a train of fs pulses (the
usual situation), it's actually not a continuum but a dense "comb" of a
hundred thousand or more optical frequency sidebands spaced apart by
exactly the (precisely defined and readily measured) repetition
frequency of the pulses (which is typically in the middle
radio-frequency range).
Turns out that in practice and without too much difficulty this
repetition frequency and hence the sideband spacing can be extremely
stable and jitter-free, giving you a precisely spaced set of optical
reference frequencies extending across an octave or more in the visible
and IR region.
With a little further trickery, sophisticated but again with reach of
available laser technology, one can adjust the exact positioning of this
comb so that not only are the spacings all equal, but each spectral line
is actually at an *exact* harmonic multiple of the repetition frequency,
so that the comb in essence extends all the way down to zero frequency.
Using standard techniques other highly stable cw or tunable lasers can
then be phase-locked to any of the individual optical comb lines -- and
now you have an optical clock or wavelength standard that's an exact
known harmonic multiple of a radio-frequency clock or time standard, or
vice versa. Opens a new era in ultra-super-precision measurements of
all kinds, for practical and basic scientific applications..
The whole subject beautifully reviewed in Ted Hansch's superb plenary
talk at CLEO/IQEC a week or so ago.
Stephen H. Westin
May27-04, 10:18 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n"J.C. Chastang" <toliary@bestweb.net> writes:\n\n> > Lehigh\'s Jean Toulouse and Iavor Veltchev are studying a phenomenon that\n> few\n> > scientists in the world have been able to achieve.\n> >\n> > Two physicists at Lehigh have produced a rainbow of visible and invisible\n> > colors by focusing laser light in a specially designed optical fiber that\n> > confines light in a glass core whose diameter is 40 times smaller than\n> that\n> > of a human hair.\n> >\n> > Full story: http://www.physorg.com/news110.html\n> >\n> > This is a very interesting phenomenon called "supercontinuum generation in\n> > nonlinear fibers", which is very difficult to achieve!\n>\n> Very interesting but what kind of physics organization(s) use(s) the\n> "diameter of a human hair" as a unit of length?\n>\n> Way down one is told:\n>\n> *A micron is one one-millionth of a meter; 2.5 microns is roughly\n> one-fourtieth [sic] the thickness of a typical human hair*\n\nSo they are off by at least a factor of 2: typical hairs are in the\nrange around 40-50um.\n\n--\n-Stephen H. Westin\nAny information or opinions in this message are mine: they do not\nrepresent the position of Cornell University or any of its sponsors.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"J.C. Chastang" <toliary@bestweb.net> writes:
> > Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that
> few
> > scientists in the world have been able to achieve.
> >
> > Two physicists at Lehigh have produced a rainbow of visible and invisible
> > colors by focusing laser light in a specially designed optical fiber that
> > confines light in a glass core whose diameter is 40 times smaller than
> that
> > of a human hair.
> >
> > Full story: http://www.physorg.com/news110.html
> >
> > This is a very interesting phenomenon called "supercontinuum generation in
> > nonlinear fibers", which is very difficult to achieve!
>
> Very interesting but what kind of physics organization(s) use(s) the
> "diameter of a human hair" as a unit of length?
>
> Way down one is told:
>
> *A micron is one one-millionth of a meter; 2.5 microns is roughly
> one-fourtieth [sic] the thickness of a typical human hair*
So they are off by at least a factor of 2: typical hairs are in the
range around 40-50um.
--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.
Phil Hobbs
May29-04, 11:55 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Andrew wrote:\n> Lehigh\'s Jean Toulouse and Iavor Veltchev are studying a phenomenon that few\n> scientists in the world have been able to achieve.\n>\n> Two physicists at Lehigh have produced a rainbow of visible and invisible\n> colors by focusing laser light in a specially designed optical fiber that\n> confines light in a glass core whose diameter is 40 times smaller than that\n> of a human hair.\n>\n> Full story: http://www.physorg.com/news110.html\n>\n> This is a very interesting phenomenon called "supercontinuum generation in\n> nonlinear fibers", which is very difficult to achieve!\n>\nYou joke, of course. John Hall and Ted Haensch got all this started years\nago, and there are a zillion comb-generator setups out there. The reason\nit\'s such an important idea is that it\'s _easy_ once somebody discovers it.\n\nCheers\n\nPhil Hobbs\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Andrew wrote:
> Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that few
> scientists in the world have been able to achieve.
>
> Two physicists at Lehigh have produced a rainbow of visible and invisible
> colors by focusing laser light in a specially designed optical fiber that
> confines light in a glass core whose diameter is 40 times smaller than that
> of a human hair.
>
> Full story: http://www.physorg.com/news110.html
>
> This is a very interesting phenomenon called "supercontinuum generation in
> nonlinear fibers", which is very difficult to achieve!
>
You joke, of course. John Hall and Ted Haensch got all this started years
ago, and there are a zillion comb-generator setups out there. The reason
it's such an important idea is that it's _easy_ once somebody discovers it.
Cheers
Phil Hobbs
Andrew Resnick
May29-04, 11:56 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In <c92o5r\\$l6f\\$1@netlx020.civ.utwente.nl> bb_ctr wrote:\n>\n>\n>\n> Why is it so important technologically?\n>\n\nHaving a coherent spectrum that spans an octave in frequency allows for\nthe development of an optical "ruler" or clock that has allowed visible\nfrequencies to be directly locked to the Cesium frequency standard,\nusing a small tabletop full of equipment. Previously, such a feat\nrequired a room full of temperature-stabilized optical equipment.\n\nOther applications include the ability to create attosecond pulses (\nbandwidth is inversely proportional to temporal width).\n--\nAndrew Resnick, Ph. D.\nNational Center for Microgravity Research\nNASA Glenn Research Center\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In <c92o5r$l6f$1@netlx020.civ.utwente.nl> bb_ctr wrote:
>
>
>
> Why is it so important technologically?
>
Having a coherent spectrum that spans an octave in frequency allows for
the development of an optical "ruler" or clock that has allowed visible
frequencies to be directly locked to the Cesium frequency standard,
using a small tabletop full of equipment. Previously, such a feat
required a room full of temperature-stabilized optical equipment.
Other applications include the ability to create attosecond pulses (
bandwidth is inversely proportional to temporal width).
--
Andrew Resnick, Ph. D.
National Center for Microgravity Research
NASA Glenn Research Center
Juergen Appel
May29-04, 11:56 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>bb_ctr schrieb:\n\n> Why is it so important technologically?\n\nThe most precise absolute frequency measurements of optical sources are\ndone with so called "frequency combs".\n\nFor that you need a femtosecond pulsed laser source with a spectal width\nthat spans more than one octave.\n\nhttp://www.mpq.mpg.de/~haensch/chain/chain.html\n\n\n--\nGPG key:\nhttp://pgp.mit.edu:11371/pks/lookup?search=J%FCrgen+Appel&op=get\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>bb_ctr schrieb:
> Why is it so important technologically?
The most precise absolute frequency measurements of optical sources are
done with so called "frequency combs".
For that you need a femtosecond pulsed laser source with a spectal width
that spans more than one octave.
http://www.mpq.mpg.de/~haensch/chain/chain.html
--
GPG key:
http://pgp.mit.edu:11371/pks/lookup?search=J%FCrgen+Appel&op=get
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>"Andrew" <andrew_zi@nospam.yahoo.com> wrote in message news:<c9085c\\$qjm\\$1@netlx020.civ.utwente.nl>... \n> Lehigh\'s Jean Toulouse and Iavor Veltchev are studying a phenomenon that few\n> scientists in the world have been able to achieve.\n>\n> Two physicists at Lehigh have produced a rainbow of visible and invisible\n> colors by focusing laser light in a specially designed optical fiber that\n> confines light in a glass core whose diameter is 40 times smaller than that\n> of a human hair.\n>\n> Full story: http://www.physorg.com/news110.html\n>\n> This is a very interesting phenomenon called "supercontinuum generation in\n> nonlinear fibers", which is very difficult to achieve!\n\nThis and other articles can be found at\nhttp://optics.org/\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Andrew" <andrew_zi@nospam.yahoo.com> wrote in message news:<c9085c$qjm$1@netlx020.civ.utwente.nl>...
> Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that few
> scientists in the world have been able to achieve.
>
> Two physicists at Lehigh have produced a rainbow of visible and invisible
> colors by focusing laser light in a specially designed optical fiber that
> confines light in a glass core whose diameter is 40 times smaller than that
> of a human hair.
>
> Full story: http://www.physorg.com/news110.html
>
> This is a very interesting phenomenon called "supercontinuum generation in
> nonlinear fibers", which is very difficult to achieve!
This and other articles can be found at
http://optics.org/
Uncle Al
May29-04, 11:58 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>"Stephen H. Westin" wrote:\n>\n> "J.C. Chastang" <toliary@bestweb.net> writes:\n>\n> > > Lehigh\'s Jean Toulouse and Iavor Veltchev are studying a phenomenon that\n> > few\n> > > scientists in the world have been able to achieve.\n> > >\n> > > Two physicists at Lehigh have produced a rainbow of visible and invisible\n> > > colors by focusing laser light in a specially designed optical fiber that\n> > > confines light in a glass core whose diameter is 40 times smaller than\n> > that\n> > > of a human hair.\n> > >\n> > > Full story: http://www.physorg.com/news110.html\n> > >\n> > > This is a very interesting phenomenon called "supercontinuum generation in\n> > > nonlinear fibers", which is very difficult to achieve!\n> >\n> > Very interesting but what kind of physics organization(s) use(s) the\n> > "diameter of a human hair" as a unit of length?\n> >\n> > Way down one is told:\n> >\n> > *A micron is one one-millionth of a meter; 2.5 microns is roughly\n> > one-fourtieth [sic] the thickness of a typical human hair*\n>\n> So they are off by at least a factor of 2: typical hairs are in the\n> range around 40-50um.\n>\n> --\n> -Stephen H. Westin\n> Any information or opinions in this message are mine: they do not\n> represent the position of Cornell University or any of its sponsors.\n\nTake a micrometer and do some surveying. I lean more toward 60\nmicrons average diameter for an average Caucasian human hair. Round\nheavliy pigmented hairs are thicker - Asians. You might have been\ntalking with a machinist about his standard of fine lineal\nperturbation, the RCH.\n\n--\nUncle Al\nhttp://www.mazepath.com/uncleal/qz.pdf\nhttp://www.mazepath.com/uncleal/eotvos.htm\n(The parity Eotvos experiment is queued)\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Stephen H. Westin" wrote:
>
> "J.C. Chastang" <toliary@bestweb.net> writes:
>
> > > Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that
> > few
> > > scientists in the world have been able to achieve.
> > >
> > > Two physicists at Lehigh have produced a rainbow of visible and invisible
> > > colors by focusing laser light in a specially designed optical fiber that
> > > confines light in a glass core whose diameter is 40 times smaller than
> > that
> > > of a human hair.
> > >
> > > Full story: http://www.physorg.com/news110.html
> > >
> > > This is a very interesting phenomenon called "supercontinuum generation in
> > > nonlinear fibers", which is very difficult to achieve!
> >
> > Very interesting but what kind of physics organization(s) use(s) the
> > "diameter of a human hair" as a unit of length?
> >
> > Way down one is told:
> >
> > *A micron is one one-millionth of a meter; 2.5 microns is roughly
> > one-fourtieth [sic] the thickness of a typical human hair*
>
> So they are off by at least a factor of 2: typical hairs are in the
> range around 40-50um.
>
> --
> -Stephen H. Westin
> Any information or opinions in this message are mine: they do not
> represent the position of Cornell University or any of its sponsors.
Take a micrometer and do some surveying. I lean more toward 60
microns average diameter for an average Caucasian human hair. Round
heavliy pigmented hairs are thicker - Asians. You might have been
talking with a machinist about his standard of fine lineal
perturbation, the RCH.
--
Uncle Al
http://www.mazepath.com/uncleal/qz.pdf
http://www.mazepath.com/uncleal/eotvos.htm
(The parity Eotvos experiment is queued)
Fleetie
May31-04, 06:26 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n"Andrew Resnick" wrote:\n> Other applications include the ability to create attosecond pulses (\n> bandwidth is inversely proportional to temporal width).\n\nHmm, well, forgive my utter ignorance. I\'m aware of the reciprocal\nrelationship between pulse width and spectral width; it\'s just\nFourier. But I don\'t understand how having a wide-bandwidth\n(splayed out all over the visible spectrum) source actually facilitates\ngeneration of ultra-narrow pulses.\n\nI see in my ignorance how an ultra-narrow pulse can\'t be\nvery "monochromatic", but I don\'t see how to "go the other\nway".\n\nEn"light"en?\n\n\nMartin\n--\nM.A.Poyser Tel.: 07967 110890\nManchester, U.K. http://www.fleetie.demon.co.uk\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Andrew Resnick" wrote:
> Other applications include the ability to create attosecond pulses (
> bandwidth is inversely proportional to temporal width).
Hmm, well, forgive my utter ignorance. I'm aware of the reciprocal
relationship between pulse width and spectral width; it's just
Fourier. But I don't understand how having a wide-bandwidth
(splayed out all over the visible spectrum) source actually facilitates
generation of ultra-narrow pulses.
I see in my ignorance how an ultra-narrow pulse can't be
very "monochromatic", but I don't see how to "go the other
way".
En"light"en?
Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk
Repeating Rifle
May31-04, 04:23 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>in article Dj5uc.10\\$U21.7@newsfe3-gui, Fleetie at\nfleetie@fleetie.demon.co.uk wrote on 5/31/04 4:26 AM:\n\n>\n> "Andrew Resnick" wrote:\n>> Other applications include the ability to create attosecond pulses (\n>> bandwidth is inversely proportional to temporal width).\n>\n> Hmm, well, forgive my utter ignorance. I\'m aware of the reciprocal\n> relationship between pulse width and spectral width; it\'s just\n> Fourier. But I don\'t understand how having a wide-bandwidth\n> (splayed out all over the visible spectrum) source actually facilitates\n> generation of ultra-narrow pulses.\n>\n> I see in my ignorance how an ultra-narrow pulse can\'t be\n> very "monochromatic", but I don\'t see how to "go the other\n> way".\n>\n> En"light"en?\n>\n>\n> Martin\nGoogle PULSE COMPRESSION or MATCHED FILTER.\n\nBill\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>in article Dj5uc.10$U21.7@newsfe3-gui, Fleetie at
fleetie@fleetie.demon.co.uk wrote on 5/31/04 4:26 AM:
>
> "Andrew Resnick" wrote:
>> Other applications include the ability to create attosecond pulses (
>> bandwidth is inversely proportional to temporal width).
>
> Hmm, well, forgive my utter ignorance. I'm aware of the reciprocal
> relationship between pulse width and spectral width; it's just
> Fourier. But I don't understand how having a wide-bandwidth
> (splayed out all over the visible spectrum) source actually facilitates
> generation of ultra-narrow pulses.
>
> I see in my ignorance how an ultra-narrow pulse can't be
> very "monochromatic", but I don't see how to "go the other
> way".
>
> En"light"en?
>
>
> Martin
Google PULSE COMPRESSION or MATCHED FILTER.
Bill
AES/newspost
May31-04, 04:23 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>In article <Dj5uc.10\\$U21.7@newsfe3-gui>,\n"Fleetie" <fleetie@fleetie.demon.co.uk> wrote:\n\n> Hmm, well, forgive my utter ignorance. I\'m aware of the reciprocal\n> relationship between pulse width and spectral width; it\'s just\n> Fourier. But I don\'t understand how having a wide-bandwidth\n> (splayed out all over the visible spectrum) source actually facilitates\n> generation of ultra-narrow pulses.\n\nStarting with two intense and monochromatic enough lines with a given\ndifference frequency, one can use nonlinear optical techniques (Raman,\noptical Kerr effect) to have the beating between these two frequencies\nmodulate and thus put additional sidebands on the two original\nfrequencies, with the same difference frequency. Extend or cascade this\nprocess far enough and you can generate a very broad "comb". Depending\non the nonlinear process and the dispersion properties of the system,\nthe sidebands in the comb may be sufficiently in phase to generate very\nshort pulses (it helps if there is minimum or zero group velocity\ndispersion, so that the sidebands all travel down the fiber or thru the\nnonlinear medium at the same group velocity). If the sidebands are not\nso phased (and there aren\'t too many of them) you can disperse the\nspectrum; put each individual component through a separate pixel on a\nliquid crystal phase modulator; and twiddle individual phases until you\ndo get the shortest available pulse for that spectral width and shape.\nThat\'s how some of the attosecond systems work.\n\n[Note: In this latter case, since the number of pixels or spectral lines\nyou can handle in this way has some practical limits, what you want is a\ncomb with wide spectral spacing. You then end up with the widest\nspectrum for that given line spacing, leading to the shortest pulses --\nbut they occur at the high repetition rate corresponding to the wide\nspacing, which is not always all that convenient.]\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>In article <Dj5uc.10$U21.7@newsfe3-gui>,
"Fleetie" <fleetie@fleetie.demon.co.uk> wrote:
> Hmm, well, forgive my utter ignorance. I'm aware of the reciprocal
> relationship between pulse width and spectral width; it's just
> Fourier. But I don't understand how having a wide-bandwidth
> (splayed out all over the visible spectrum) source actually facilitates
> generation of ultra-narrow pulses.
Starting with two intense and monochromatic enough lines with a given
difference frequency, one can use nonlinear optical techniques (Raman,
optical Kerr effect) to have the beating between these two frequencies
modulate and thus put additional sidebands on the two original
frequencies, with the same difference frequency. Extend or cascade this
process far enough and you can generate a very broad "comb". Depending
on the nonlinear process and the dispersion properties of the system,
the sidebands in the comb may be sufficiently in phase to generate very
short pulses (it helps if there is minimum or zero group velocity
dispersion, so that the sidebands all travel down the fiber or thru the
nonlinear medium at the same group velocity). If the sidebands are not
so phased (and there aren't too many of them) you can disperse the
spectrum; put each individual component through a separate pixel on a
liquid crystal phase modulator; and twiddle individual phases until you
do get the shortest available pulse for that spectral width and shape.
That's how some of the attosecond systems work.
[Note: In this latter case, since the number of pixels or spectral lines
you can handle in this way has some practical limits, what you want is a
comb with wide spectral spacing. You then end up with the widest
spectrum for that given line spacing, leading to the shortest pulses --
but they occur at the high repetition rate corresponding to the wide
spacing, which is not always all that convenient.]
Johannes Swartling
Mar12-06, 04:00 AM
"bb_ctr" <bb_ctr@nospam.yahoo.com> wrote in message
news:c92o5r$l6f$1@netlx020.civ.utwente.nl...
>
>
>
> Why is it so important technologically?
Depends of course on what you mean by important - maybe not like the
invention of the wheel, but in the context of laser development it's
important. A short-pulse supercontinuum can be useful for a number of cool
things, such as making even shorter laser pulses, and a whole range of
time-resolved spectroscopy applications. Another example is to use it as a
light source for optical coherence tomography to make sub-micron resolution
possible.
Johannes
Johannes Swartling
Mar12-06, 04:00 AM
"Andrew" <andrew_zi@nospam.yahoo.com> wrote in message
news:c9085c$qjm$1@netlx020.civ.utwente.nl...
>
>
> Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that
few
> scientists in the world have been able to achieve.
>
> Two physicists at Lehigh have produced a rainbow of visible and invisible
> colors by focusing laser light in a specially designed optical fiber that
> confines light in a glass core whose diameter is 40 times smaller than
that
> of a human hair.
>
> Full story: http://www.physorg.com/news110.html
>
> This is a very interesting phenomenon called "supercontinuum generation in
> nonlinear fibers", which is very difficult to achieve!
Supercontinuum generation in non-linear fibers is routine in laser labs
everywhere and has been for a few years. A pretty strange press release for
something which is not really new.
Johannes
Lostgallifreyan
Mar12-06, 04:00 AM
"Johannes Swartling" <johannes.swartling@home.se> wrote in
news:c9250b$57f$1@newsserver.cilea.it:
> Supercontinuum generation in non-linear fibers is routine in laser
> labs everywhere and has been for a few years. A pretty strange press
> release for something which is not really new.
>
> Johannes
>
There is so much I don't know... :) But unless I'm missing something even
in what I thought I knew, this is odd. Even at a few thousand dollars per
meter of special fibre, that alone wouldn't stop there being fully tunable
diode-based lasers. If this supercontinuum generation were routine, I'd
have thought these lasers would be a seriously desireable and much talked
about icon, a holy grail for light show makers, for one thing, yet I've
never heard of that. Can their output be coherent, if it's in a wide
spectrum? And even if not, can the source be tuned and coupled to a fibre
or other means of making a tiny bright source for collimating?
j.m.1491@gmx.net
Mar13-06, 04:00 AM
Lostgallifreyan wrote:
> "Johannes Swartling" <johannes.swartling@home.se> wrote in
> news:c9250b$57f$1@newsserver.cilea.it:
>
>> Supercontinuum generation in non-linear fibers is routine in laser
>> labs everywhere and has been for a few years. A pretty strange press
>> release for something which is not really new.
>>
>> Johannes
>>
>
> There is so much I don't know... :) But unless I'm missing something even
> in what I thought I knew, this is odd. Even at a few thousand dollars per
> meter of special fibre, that alone wouldn't stop there being fully tunable
> diode-based lasers.
Supercontinuum has about the same tuneability as a light bulb. If you
add a monochromator you can select a wavelength, but the source itself
is, well, a continuum. Very wide spectrum, but white.
About diodes: Most diodes will not give you short enough pulses with
high enough peak powers to create a supercontinuum.
> If this supercontinuum generation were routine,
http://www.google.ca/search?hl=en&q=supercontinuum+generation
http://www.google.ca/search?hl=en&q=supercontinuum+comb
http://www.google.ca/search?q=supercontinuum+optical+frequency+metrolog y
http://www.google.ca/search?hl=en&q=supercontinuum+spectroscopy
and so on...
> I'd
> have thought these lasers would be a seriously desireable and much talked
> about icon, a holy grail for light show makers,
A continuum in visible wavelength range is white. What light shows like
to have are a few base colors, modulated separately.
> for one thing, yet I've
> never heard of that. Can their output be coherent, if it's in a wide
> spectrum?
Usually it's created with ultrashort pulses. In a first approximation
it's coherent as long as the pulse lasts, i.e. there is a fixed phase
relation between the individual frequencies, as in an ordinary
femtosecond pulse e.g. created by a Ti:Sapphire laser. If you overlap
multiple pulses you may not find any coherence, or extremly short
coherence time. If you look in detail at one pulse, you can have the
situation that the pulse splits up in multiple pulses, each with a
different center wavelength. Then it's getting problematic to define
what you mean with coherence.
> And even if not, can the source be tuned and coupled to a fibre
> or other means of making a tiny bright source for collimating?
The way to create this continuum creation works is by using nonlinear
optical effects. Doing that in fibers keeps the power needed down
because you can maintain a high intensity over a long propagation
distance (until GVD kills you). Photonic crystal fibers are nice because
you can engineer the GVD and make very small modes.
So, yes, it's possible to make this tiny source.
HTH,
j.m.
Johannes Swartling
Nov4-06, 03:27 PM
"bb_ctr" <bb_ctr@nospam.yahoo.com> wrote in message
news:c92o5r$l6f$1@netlx020.civ.utwente.nl...
>
>
>
> Why is it so important technologically?
Depends of course on what you mean by important - maybe not like the
invention of the wheel, but in the context of laser development it's
important. A short-pulse supercontinuum can be useful for a number of cool
things, such as making even shorter laser pulses, and a whole range of
time-resolved spectroscopy applications. Another example is to use it as a
light source for optical coherence tomography to make sub-micron resolution
possible.
Johannes
Johannes Swartling
Nov4-06, 03:27 PM
"Andrew" <andrew_zi@nospam.yahoo.com> wrote in message
news:c9085c$qjm$1@netlx020.civ.utwente.nl...
>
>
> Lehigh's Jean Toulouse and Iavor Veltchev are studying a phenomenon that
few
> scientists in the world have been able to achieve.
>
> Two physicists at Lehigh have produced a rainbow of visible and invisible
> colors by focusing laser light in a specially designed optical fiber that
> confines light in a glass core whose diameter is 40 times smaller than
that
> of a human hair.
>
> Full story: http://www.physorg.com/news110.html
>
> This is a very interesting phenomenon called "supercontinuum generation in
> nonlinear fibers", which is very difficult to achieve!
Supercontinuum generation in non-linear fibers is routine in laser labs
everywhere and has been for a few years. A pretty strange press release for
something which is not really new.
Johannes
Lostgallifreyan
Nov4-06, 03:27 PM
"Johannes Swartling" <johannes.swartling@home.se> wrote in
news:c9250b$57f$1@newsserver.cilea.it:
> Supercontinuum generation in non-linear fibers is routine in laser
> labs everywhere and has been for a few years. A pretty strange press
> release for something which is not really new.
>
> Johannes
>
There is so much I don't know... :) But unless I'm missing something even
in what I thought I knew, this is odd. Even at a few thousand dollars per
meter of special fibre, that alone wouldn't stop there being fully tunable
diode-based lasers. If this supercontinuum generation were routine, I'd
have thought these lasers would be a seriously desireable and much talked
about icon, a holy grail for light show makers, for one thing, yet I've
never heard of that. Can their output be coherent, if it's in a wide
spectrum? And even if not, can the source be tuned and coupled to a fibre
or other means of making a tiny bright source for collimating?
j.m.1491@gmx.net
Nov4-06, 03:27 PM
Lostgallifreyan wrote:
> "Johannes Swartling" <johannes.swartling@home.se> wrote in
> news:c9250b$57f$1@newsserver.cilea.it:
>
>> Supercontinuum generation in non-linear fibers is routine in laser
>> labs everywhere and has been for a few years. A pretty strange press
>> release for something which is not really new.
>>
>> Johannes
>>
>
> There is so much I don't know... :) But unless I'm missing something even
> in what I thought I knew, this is odd. Even at a few thousand dollars per
> meter of special fibre, that alone wouldn't stop there being fully tunable
> diode-based lasers.
Supercontinuum has about the same tuneability as a light bulb. If you
add a monochromator you can select a wavelength, but the source itself
is, well, a continuum. Very wide spectrum, but white.
About diodes: Most diodes will not give you short enough pulses with
high enough peak powers to create a supercontinuum.
> If this supercontinuum generation were routine,
http://www.google.ca/search?hl=en&q=supercontinuum+generation
http://www.google.ca/search?hl=en&q=supercontinuum+comb
http://www.google.ca/search?q=supercontinuum+optical+frequency+metrolog y
http://www.google.ca/search?hl=en&q=supercontinuum+spectroscopy
and so on...
> I'd
> have thought these lasers would be a seriously desireable and much talked
> about icon, a holy grail for light show makers,
A continuum in visible wavelength range is white. What light shows like
to have are a few base colors, modulated separately.
> for one thing, yet I've
> never heard of that. Can their output be coherent, if it's in a wide
> spectrum?
Usually it's created with ultrashort pulses. In a first approximation
it's coherent as long as the pulse lasts, i.e. there is a fixed phase
relation between the individual frequencies, as in an ordinary
femtosecond pulse e.g. created by a Ti:Sapphire laser. If you overlap
multiple pulses you may not find any coherence, or extremly short
coherence time. If you look in detail at one pulse, you can have the
situation that the pulse splits up in multiple pulses, each with a
different center wavelength. Then it's getting problematic to define
what you mean with coherence.
> And even if not, can the source be tuned and coupled to a fibre
> or other means of making a tiny bright source for collimating?
The way to create this continuum creation works is by using nonlinear
optical effects. Doing that in fibers keeps the power needed down
because you can maintain a high intensity over a long propagation
distance (until GVD kills you). Photonic crystal fibers are nice because
you can engineer the GVD and make very small modes.
So, yes, it's possible to make this tiny source.
HTH,
j.m.
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