Subj:   HeCd laser (442nm)
The following question was addressed
From: [log in to unmask] (Jerzy Dobrucki)
>I would greatly appreciate some input from the users a HeCd
laser (442 nm line) for confocal work (pH with BCECF or any other
applications?):
 
>1. is noise a problem with this laser (are you using Liconics or
Omnichrome; which type?)
>2. is long term stability a problem?
>3. have you tried to use the 325 nm line - was it useful for confocal
imaging?
 
Many thanks in advance for any information.
 
Jurek Dobrucki
Jagiellonian University
[log in to unmask]
 
Response:
I cannot respond as to the applications however HeCd lasers in the UV and Vis
have been used in Confocal.  The difficulty with the 325nm wavelength when
launched through the entire system is the transmission and wavelength
correction of the optics.  A few years ago BioRad Japan developed some optics
for the 325nm laser and I think Leica has a 100X 325 objective.  If launched
 through the Epi port for Cage Compounds you will not experience the optic
transmission problem. 325 has been used in Flow for Indo calcium probes for
 many years.   As for 442nm, Lucifer Yellow, chromomiesan and some other dyes
have peak absorbtion.
The lifetime currently is around 4000 hours for these products and the long
term reliability is similar to other Gas Laser products.  You are typically
limited to about 10mW maximum for TEMoo @325nm and 100mW for TEMoo 442nm.  If
you do Cage Compounds at 325 you can use multimode at about 40mW UV.
 
Ray Reid
Omnichrome
909-627-1594