Pulsed laser power measurement

[Carlos Sanchez-8]

Hello, good morning.

 

            We have recently purchased a Zeiss Multiphoton system with a MaiTai Deep Sea laser and we would like to measure its power from time to time. We had been using a Coherent pocket laser power meter to measure the power of conventional lasers at the 10x objective but we believe that it cannot be used for so high laser powers achieved with a pulsed laser. The only way we have found to test its right alignment and work has been to use a sample like “Convalaria”, commercial beads, etc.

            Would you recommend another easy and quantitative way to know if the pulsed laser is working perfectly and all the available power is arriving to the sample?

 

Thank you very much in advance for your help.

 

Carlos Sánchez Martín

Servicio de Microscopía Optica y Confocal (SMOC) (Lab.310)

Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM)

C/Nicolás Cabrera,1

Universidad Autónoma de Madrid. Cantoblanco.

28049. Madrid

Tlfs. 91 196 4613/4643

Fax. [phone]

E-mail: [hidden email]

Web: http://www.cbm.uam.es/confocal

[Andreas Bruckbauer]

I use a small power meter with Silicon head which has a range up to 50 mW
because we have it n the lab, better is one of the thermal sensors which go
up to a few Watts. On my mic the maximum laser power at the objective is
about 200 mW, so i set the AOM to 10% and can comfortably measure the
average laser power with the Si head, don't forget to adjust the wavelength.
When adjusted correctly by the manufacturer, the AOM is linear over a large
range. Furthermore i use the slowest scan speed not to be affected by beam
blanking too much and a 2x zoom because otherwise the power drops at the
edges of the scan area. If you want to know the power under normal
measurement conditions, choose the same objective you are using for the
measurement. I had no problem with the 20x 0.95 NA (air instead of water
imersion). Measureing the laser power is really usefull to check the
instrument is working.