Frequency Conversion

This calculator allows for easy conversions between units of wavelength, frequency, spatial frequency and energy.  Unit conversions of a range at a spectral peak location can also be done by entering bandwidth information in the same units as the spectral peak.

For those interested in estimating the transform limited temporal pulse duration determined by spectral bandwidth, simply select the expected pulse shape in the drop down.  Three types of pulse shapes are available: Gaussian, Lorentzian, and (sech)2.

  • Gaussian line shapes are useful for describing doppler broadened transitions,
  • Lorentzian line shapes describe pressure broadened transitions,
  • (sech)2 lines shapes can be used to estimate ultrashort pulses generated by mode locked lasers.

The temporal pulse  duration calculated represents the transform limited (i.e. shortest duration) FWHM of the optical pulse.

The calculation also displays the product of the bandwidth and pulse duration, the time bandwidth product, which is the theoretical limit for a pulse of a particular shape.  The ratio of the measured time bandwidth product versus the theoretical value gives the times transform limited value for the measured pulse.