Birefringent...  gummy bears!?  Will the wonders of optics never cease? @:-)
It makes sense if you think about it though; it's a gel (sort-of) so
if you put stress on its structure one way or another you will get an
order preference.

Regarding yanking crystals out of laser pointers, that's a good way to
get a cheap doubling crystal, but if you just want a test sample my
'grow crystals on a coverslip' method is a lot less work then trying
to pry the tiny dot of crystal out of one of those pointers.  KTP,
KDP, and BBO are all good doublers.  I use a commercial BBO crystal
that cost about a grand ($1k) to double our Ti:Saph now and again.  We
do fluorescence spectroscopy with it.  By tuning the Ti:Saph and
doubling it I can get ~350-520nm light.  The key thing about the BBO
crystal is it is optimal for this kind of work so I get a pretty good
conversion efficiency out of it.  A 'scrounged' crystal may not work
as well.

Craig

On Thu, Jul 8, 2010 at 9:52 AM, Peter Pitrone <[log in to unmask]> wrote:
> Hello Farid,
>
> I'd like for you to try something for me... A gummy bear (or at least a very thin slice of one)! I'm sorry if this sounds crazy, but I really would like to know what happens. I can tell you that they are very birefringent, do to trial and error. Try putting one between crossed polarizers and start to squeeze its body for a good laugh, every kid I've shown it to gets a real good kick out of it...
>
> Pete
>
> On Jul 2, 2010, at 22:11 PM, Farid Jalali wrote:
>
>> Hello Lister,
>> Hope all are doing well. Can anyone please offer me suggestions for a handy sample for imaging SHG in transmission and/or reflection? Since I am not working in a lab anymore, something that I could pick up in store would be ideal. I know its a strange request but I beg your indulgence in this regard.
>> Cheers
>> Farid
>>
>>
>