BragGrate™ Combiner

Transmitting or reflecting volume Bragg gratings for spectral beam combining

BragGrate™ Combiner is a transmitting or reflecting volume Bragg grating (or set of gratings) enabling Spectral Beam Combining (SBC) of laser radiation from multiple sources with offset wavelengths into a single nearly diffraction-limited beam with increased energy brightness. SBC by means of BragGrate™ Combiners recorded in photo-thermo-refractive (PTR) glass is a simple and robust technique for combining high-power laser radiation. Excellent mechanical properties and a refractive index, independent of temperature, enable the Combiners to withstand high-power laser radiation, thus making them ideal elements for high-powered SBC.

Spectral beam combining scheme with 4 BragGrate™ Combiners

Specifications

• Diffraction Efficiency (DE): 90-99%
• Spectral Bandwidth: 50 pm to 20 nm
• Operating Range λ: 400-2700 nm
• Grating Thickness: 0.50-10 mm
• Apertures: up to 50×50 mm²
• Angular Selectivity: 0.5-10 mrad
• Deflection Angles: 5-45 deg

Standard Parameters

• Center Wavelength: 930-980, 1030-1100 nm
• Spectral Bandwidth (FWHM): 0.2-0.5 nm
• Diffraction Efficiency 95-99%
• Lateral Dimensions: 15x15, 20x20 mm²

Spectrum of spectrally-combined output beam with total power of 780 W and channel spacing of 0.5 nm

Advantages & Features

• High power operations up to 10 kW
  
• High energy operations up to 5 J/cm²
  
• Unrestricted lifetime; no degradation of parameters has been detected for 10 years
  
• Very high angular selectivity (TBG)
  
• Very high spectral selectivity (RBG)
  
• Superior environmental stability
  
• No polarization dependence at small incident angles
• Nearly diffraction-limited beam quality

Applications

High power spectral beam combining Latest achievements: 5-beam combining with total output power of 780 W, combining efficiency of > 90%, channel spacing 0.25 nm.