For an experiment at our university we need a laser that runs at about 2.1 μm (about 20nm higher or lower would be fine too. We have found a multitude of lasers that achieve this (typically Thulium- or Holmium-doped solid state or fiber lasers), but they don't meet the requirements that we have.
Specifically, we need:
- CW output (pulsed won't work for our application).
- Single-mode emission with a linewidth of about 0.1 nm.
- Polarized output.
- The laser should be single-mode fiber-coupled (or at least have an M^2 below 1.5 or so to allow efficient fiber coupling).
- 1W of power would be perfect (500mW would be the minimum).
Many lasers around this wavelength are high power (in the range of tens of Watts), but have bad beam quality, or very broad linewidth. Medical lasers with large fiber outputs won't work for our application (they generally have fibers with hundreds of μm diameters).
Tunability of the laser would be a bonus, but isn't strictly required in our application.
One option we are considering is using an Optical Parametric Oscillator (OPO) consisting of a periodically-poled crystal (Lithium Niobate or KTP) which is phase-matched such that the frequency of a pump laser running at 1064nm if halved (which would result in a wavelength of 2128 which would still be fine for our application). It isn't trivial using such a laser in a high-power configuration though (since the signal/idler beams would have to produce 1W of power at least the pump laser would need to have several Watts).
We would appreciate any ideas or names of companies that would be able to build such a system. Thank you very much.