Advanced LIGO subsystems
are the organizational units of the overall project. Follow the links below to view the mission and progress of each subsystem.

Auxiliary Optics Core Optics
Data Acquisition Data and
Input Optics

LIGO Technology Development and Migration

Explore the menu of case study links (left) to view impacts of LIGO technology across the broader science and engineering community.

Technology Type:  Lasers

Edge-Pumped Zig-Zag Slab Laser

** Institution:  Stanford University
** Contact:  Robert L. Byer  
650.723.0226, rlbyer(at)
** Funding Agencies:  National Science Foundation and DARPA
** Technology Source:  LIGO Scientific Collaboration (LSC) members
      outside of LIGO Laboratory

 Patent Thumbnail

The September 1999 LIGO Scientific Collaboration (LSC) White Paper (1) on detector research and development produced a strawman design for an interferometer that used a 180 watt near-infrared laser. [rlb zzsl]This lead to a competition among laser groups within the LSC to produce a diode laser pumped solid state laser that could meet the stringent Advanced LIGO requirements. In particular a competition began between three LSC groups investigating end pumped rod lasers, unstable optical resonator and zig-zag slab laser geometries. The invention of the edge-pumped zig-zag slab laser (U.S. Patent 6,134,258) resulted from this research.

Improvements in the brightness of laser-diode pump sources, both fiber-coupled and bare arrays, have provided the ability to push the limits of high-power solid-state laser design. Stress-induced birefringence, thermal lensing, and the stress-fracture limit make scaling of rod lasers [rlb zzsl]to high average powers difficult when good beam quality is required. Zigzag slab geometry lasers have been scaled to high average power levels while maintaining good beam quality and polarization contrast. However, practical use of slab lasers has been limited by the low laser efficiency that is typically seen in side-pumped slab lasers and by the complexity of the pumping and cooling through the same surface in the slab laser-head design. This zigzag slab laser design is based on conduction cooling and a novel pumping geometry called transverse or edge pumping. The edge-pumping geometry decouples the cooling and optical pumping interfaces, simplifying the laser-head design. The advantages of this design include efficient pump light absorption, acceptance of high-numerical-aperture pump sources, uniform conductive cooling, and scalability to higher power.


1.  LSC White Paper on Detector Research and Development  E.K. Gustafson, D. Shoemaker, K. Strain and R. Weiss  LIGO T990080-00-D

Explore Advanced LIGO    Construction Schedule
   Instrumentation and Astrophysics
   An Overview of the Upgrades
   The International Partnership
   Science Impacts
   LIGO Technology Transfers
   LIGO Scientific Collaboration
   Public Outreach
   LIGO Magazine
   aLIGO Home