Hydrothermal Crystal Growth that Eliminates Spontaneous Emission (2011-108)

Market Overview:

This hydrothermal approach to growing single crystal oxide hosts resolves the issues posed by amplified spontaneous emission (ASE). ASE is the result of unwanted internal reflection of photons at the lasing frequency within the laser crystal. The consequences of ASE include induced emission of ions from the excited state and unwanted internal lasing in random directions. These effects take away the needed amount of power from the laser and severely inhibit the performance of the lasers. From an economic standpoint, the global market for solid state lasers is projected to steadily increase, reaching $850 million by 2020. This steady growth is primarily due to the demand for lasers with operational thresholds that can be reached at relatively low intensities of laser pumping. Clemson University researchers have developed a hydrothermal crystal growth process that minimizes ASE and its negative effects by growing layers of doped host crystals that contain absorbing ions. The approach results in improving the quality of high power lasers and overall laser performance by minimizing or eliminating ASE.



Optics; High power lasers



• Improves power and beam quality by eliminating ASE, enabling the creation of new products with improved lasing properties

• Introduces layers of doped host crystal around the edges of the lasing crystal as protection, preventing reflection of the spontaneous photons but not interfering with the coherent and directional lasing photons created by the stimulated emission 


Technical Summary

This approach to hydrothermal growth of single crystal oxide hosts reduces ASE and its resulting negative effects. Typically, a solid-state laser cavity contains a host material that is doped with a small amount of an activator ion. This specific approach creates single crystal oxide hosts doped with lasing ions containing layers of doped ions that suppress ASE.  Clemson University researchers employed a method to grow layers of doped host crystal on the edges and faces of the laser crystal that contain absorbing ions that help eliminate the internally reflected photons. This ultimately minimizes ASE, resulting in improved laser performance and the potential for new products within the optics industry.


Stage of Development

Validated Prototype


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Inventors:                        Joseph Kolis, Colin McMillen


Application Type:            Non-provisional


Serial Number:                61/663,090


CURF Ref No:                  2011-108



Patent Information:
Advanced Materials
For Information, Contact:
Andy Bluvas
Technology Commercialization Officer
Clemson University Research Foundation
Joseph Kolis
Colin Mcmillen
Photonic Crystals
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