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Tunable Diode Lasers - Common topics

1. FAQ

1.1. I just received my tuneable diode laser but I cannot get it to emit light

Please check the following points: 

  1. Is the control rack/power supply connected to a mains outlet?
  2. Is the interlock connector in place?
  3. Is the mains switch on the back side of the power supply switched on?
  4. Is the key lock switch on the monitor unit switched on?
  5. (If 1 - 4 are fulfilled and still the display module does not come on, i.e. there is no background illumination of the dot matrix display or no welcome message, please refer to FAQ 2).
  6. Is the current control module (DCC) connected to the laser head and are the locking screws tightened?
  7. Is the DCC operation LED (yellow) at the laser on?
  8. Is the shutter open?

1.2. Which tools are necessary to verify proper operation of my laser?

We highly recommend the use of a high-finesse interferometer, such as the FPI 100 from TOPTICA for characterizing the spectral properties of your laser, such as single-mode operation and mode-hop-free tuning range. Our experience shows that customers without such a tool spend significantly more time verifying correct operation of their laser system.

A well calibrated spectrometer such as an optical spectrum analyzer or a high precision wavelength meter (e.g. the WSx series from High Finesse) also proves useful for precise and rapid coarse tuning of the laser. This is especially important if the laser is operated at wavelengths where no atomic/molecular reference exists.

For verification of the laser power a high quality power meter is indispensable:

1.3. Life time of a semiconductor laser as a function of current

There is an empirical relation between current and specified life time

L_op = L_spec * (I_op / I_spec)^(- n)

where n is a factor between 1.5 and 2.0 for  laser diodes base on GaAs.The factor n has to be determined for experimentally by doing sample life time measurements for a each batch of diodes. Assuming a factor of 1.5, a reduction of the operating current to half of the maximum rated current would increase the lifetime by a factor of 2.8, for example.