Re: Argon ion laser - age/noise and effect on images..?

Posted by Stephen Cody-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Argon-ion-laser-age-noise-and-effect-on-images-tp7586010p7586015.html

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Hi Jacqui,

I would expect you'd see black horizontal lines if the laser was failing. If you are seeing a grainy image (I'm presuming a noisy image); increasing laser power though AOTF and decreasing PMT gain (HV) should make it go away.

Cheers Steve

Stephen H. Cody

On 18 Nov. 2016, at 8:26 am, [hidden email] wrote:

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Hi Jacqui,
Could your laser have just gone out of alignment? This happens quite regularly on our old SP2.
cheers,
Rosemary
PI Int Dr

Dr Rosemary White
CSIRO Black Mountain
GPO Box 1700
Canberra, ACT 2601
Australia

T 61 2 6246 5475
E [hidden email]

From: Confocal Microscopy List <[hidden email]> on behalf of Jacqui Ross <[hidden email]>
Reply-To: Confocal Microscopy List <[hidden email]>
Date: Friday, 18 November 2016 11:19 am
To: "[hidden email]" <[hidden email]>
Subject: Argon ion laser - age/noise and effect on images..?

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Hi everyone,

 

I’m hoping that someone can help me to confirm whether an effect I am seeing with one of our confocal  microscopes is likely to be due to the ageing of an argon ion multiline laser.

 

The laser is about 8 years old and the power level has dropped to about 1/3 of the original output but we are still able to excite the fluorophores very well at AOTF controlled percentages <5%.

 

What I’m noticing is that when I use the argon ion laser, e.g. 488nm line, the images look much more granular than when using other lasers when similar voltages are being used at the PMT. I’ve checked the other detectors and it doesn’t seem to be related to the PMTs.

 

Much slower speeds and more averaging do improve the images but I’m puzzled by this as the issue is there even when the Master gain/voltage is at a level which I wouldn’t normally need to go slower/average as much.

 

Can anyone tell me whether the age of the laser can cause issues like this? I’m wondering if we should just replace it. We only normally replace lasers when they expire.

 

Or if there are some tests that I can do to further define the issue?

 

The last measurements were as below for 8A with two different beam splitters;

 

488nm              0.51mW (NT 80/20)                    2.31mW (MBS488)        

Thanks in advance for any ideas.

 

Cheers,

 

Jacqui

Jacqueline Ross

Biomedical Imaging Microscopist
Biomedical Imaging Research Unit (BIRU)
School of Medical Sciences 
Faculty of Medical & Health Sciences
The University of Auckland
Private Bag 92019
Auckland 1142, NEW ZEALAND

Telephone: Ext 87438; DDI:  +64 9 923 7438

Website:    http://www.auckland.ac.nz/biru