W. M. Keck Microscopy Center


W. M. Keck Microscopy Center Homepage

Lasers on the Leica SP1 Confocal


The Leica SP1 has three lasers:

    1) 64mW argon ion laser with lines at 457 and 488 nm. 2) 10mW DPSS laser with a 568 nm line

    3) 10mW helium-neon laser with a 633 nm line.

Be sure to check the full excitation and emission spectra of your fluorophores - particularly with multiple labels. Many spectra are available on Molecular Probes' web site at http://www.probes.com

The 457 line excites CFP.
The 488 line excites GFP, Alexa 488, Cy2, fluorescein, and Propidium Iodide.
The 561 line excites the RFPs, Alexa 568 and 555, Cy3, Rhodamine, Texas Red and Propidium Iodide.
The 633 line excites Alexa 633 and 647, Cy5 and ToPro3


The argon laser is air-cooled. The main (red) switch turns on the cooling fan(s). The main switch is turned on before the laser and must remain on for at least five minutes after the laser key is turned off so the fan will continue to cool the laser.

The key turns on the high voltage supply for the laser tube. Turn the key briefly to start and then release to the on position.

The argon laser has an intensity adjustment.

When turning on the laser, the intensity adjustment will be fully counterclockwise (MIN). This is a current control mode. In this mode, the laser tube current is held constant but the output power, or light intensity, can vary due to changes in ambient temperature and electronic noise. Do not leave the laser in this mode when imaging.

In the light control mode, the output power, or light intensity, is kept constant by varying the laser tube current. Turn up the level control to the 9 O'Clock position.Use the minimum setting necessary since turning up the level decreases the life of the laser.

For quantification experiments, wait 30 minutes after changing the laser power for the laser to stabilize.

When to turn off the lasers:
In the Keck Center, the lasers are turned on as they are used and left on for the rest of the day or scheduled period. The last user of the day turns ALL of the lasers off. Each on/off cycle reduces the life of the laser.

When there is a question, if the lasers won't be used for at least hours, then turn them off.


Contact Nathaniel Peters at ncpeters@uw.edu for additional information. Suggestions and comments are always welcome!

© 2016 W. M. Keck Microscopy Center, University of Washington