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.
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
- 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.