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Diode Lasers

Nowadays diode lasers are a very crucial part of life: scanning cash registers, DVD's, DSL (data transfer in optical fibre cables), laser pointers, laser printers, instant photo printing, etc.

However, for many other applications the power, power density, or the spectral properties are not sufficient (laser beamer, laser spectroscopy, material processing, many medical applications, welding, cutting, etc.)

We can help you to match light from semiconductor lasers onto your applications.

Power scaled diode laser

Four lasers are spectrally multiplexed so they maintain their beam quality and scale up their output power. (read more on separate page)

Compact laser with high power density
Patented compact laser which emits about 0.5W almost diffraction limited light
3D-Animation of a compact diode laser with external resonator
Tuning range of a diode laser
Tuning range of a diode laser in the infrared spectral region
Beam quality of an ECDL
Beam quality of a diode laser in an external cavity (ECDL)
Sketch of patented concept
Sketch of patented concept

External Resonators

External resonators offer many ways to taylor the light out of the diode laser:

  • Increasing the power density by improving the beam quality through selective amplification of suitable transverse laser modes
  • Increasing the spectral power density
  • Tuning the wavelength
  • Stabilising power and wavelength against thermal drift
  • Converting wavelengths into other spectral regions by means of nonlinear effects
Material Processing
Short video demonstrating simple material processing

Material Processing

With a patented design (more), a demonstrator was built which improved the beam quality of the laser diode from M²>40 to M²<1.5 and also yields more than 0.5W of output power in a well controlled beam. Thereby marking and engraving can be realised over great distances.

spectral multiplexing
Multiple lasers with graduated wavelengths are superimposed for upscaled output power
coherent coupling (principle)
A multitude of beams is superimposed with correct phases so that unwanted diffraction orders destructively interfere
coherent coupling
By means of coherent coupling, multiple lasers can be combined into a single beam without dispensing with spectral purity

Purpose-built External Resonators

  • Increasing the performance of the laser beam by spectral beam combining (SBC):
    • Several lasers get stabilised to neighbouring wavelengths.
    • Those can be superimposed at a dispersive element (i.e. a grating).
    • Output will be a beam, with a beam quality of a single laser, which carries the power of all lasers used.
    • The resulting laser beam is spectrally wider than from a single laser.
    • This can reduce speckles.
  • Coherent coupling through the use of several laser active areas in a common resonator:
    • Very sophisticated resonators, because in principle, interference effects are used.
    • Hence, exact positioning in the sub-wavelengths area is needed.
  • Generation of coherent light in completely different wavelength areas by using non-linear effects:
    • Second harmonics generation (SHG).
    • Generation of blue and green light.
    • They are spectrally stabilized and can even be tunable if needed.
    • Direct electronic modulation.


  • Ultrashort pulses (ps). In a certain sense this is also a coherence phenomenon, insofar as several longitudinal modes posses a fixed phase relation with one another.