*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopyPost images on
http://www.imgur.com and include the link in your posting.
*****
On Wed, Jan 29, 2020 at 10:25 AM micro <
[hidden email]>
wrote:
>
> I'm leaning toward the refurb because of the power and the price. Is there
> anything obvious that I should be aware of buying refurbished lasers? I
> will be checking to see if the guarantees offered by the company are
> satisfactory. ?
>
Do you actually need a laser with 5x the power? Would you be able to make
use of it with bleaching/FRAP experiments etc? Will you have to re-train
your users to not inadvertently fry their samples?
>
> I'm also being told that the 561nm laser is the most expensive of the four
> major ones for confocal (405,488,561,640nm)- is this true?
>
Yes. 561 and 488 are currently the most expensive, with 561 probably being
somewhat the higher of the two. This is because they are diode-pumped solid
state lasers (DPSS). There are no laser diodes that produce 561 directly,
so in practice a NIR diode laser is frequency doubled with a
temperature-controlled crystal to generate 561nm light.* 488 is also
usually produced this way, although there are now direct-488nm diodes (DD)
available which will start to slowly phase out the DPSS models. The
lifespan of DPSS lasers tends to depend on the crystal oven that controls
the doubling, as well as the quality of the NIR pump diodes, light
delivery, etc. There are a number of things that can go wrong. They are
also difficult to modulate, because the doubling process has a particular
minimum value, and the final output is also not directly linear with input.
This means that most DPSS lasers are run full power all the time, with an
external modulator actually controlling the power. In short, a refurb model
will have had one critical subsystem of the whole fail, which will be
replaced and then the laser can be resold. For such a laser I would want
some sort of extended warranty or guarantee of the condition and lifetime
of the other original components in the system. Nikon's offer of 1/3 of the
price is attractive, but you should look to see what is covered, and for
how long.
Craig
>
>
> Thanks in advance,
>
> Chris
>
>
> --
> Dr. Chris Law (He/Him)
> Microscopy Specialist
> Centre for Microscopy and Cellular Imaging
> SP553.05 - Biology Dept.
> Loyola Campus of Concordia University
> 7141 Sherbrooke W.
> Montréal
> QC
> H4B 1R6
>
Locked
