Multi-Stage Raman Amplifier

Technology #11533

Key Points

  • Multi-stage diamond Raman Master Oscillator Power Amplifier (MOPA)
  • Pulse energy at 2nd Stokes (1485 nm) can be scaled to higher levels compared to other diamond Raman laser designs, wherein both 1st and 2nd Stokes resonate in the same oscillator
  • Applications include LIDAR, infrared sensing, directed energy, range finding, target illumination, laser material processing and medical

Abstract

The University of Central Florida invention is a multi-stage diamond Raman Master Oscillator Power Amplifier (MOPA). Raman lasers, in general, do not require rare-earth doping, as the vibrational modes of the atomic structure or crystal lattice are the media for the effect. It is a nonlinear effect, and as such, the gain is proportional to the intensity of the 1st Stokes signal and the pump. Diamond Raman lasers have proven to be very valuable, as the large Raman shift allows access to otherwise difficult wavelength regions while using well-developed lasers as pumps. Also, as the thermal conductivity of diamond is the highest of any bulk material, such lasers are very resistant to thermal lensing. Normally, the caveat of Raman lasers is the limited gain achievable in 1st Stokes before 2nd Stokes is generated; the onset of 2nd Stokes saturates the pump depletion. This means a specific design for a Raman laser works typically only across a relatively narrow range of input intensities (that is, high threshold and low maximum scalability).