Reflecting Bragg Grating (RBG) for spatial filtering
Imperfections in laser optics and variations in laser gain medium cause side fringes and spatially varying intensity. Our spatial filters are designed to “clean up” laser beams from these deficiencies. BragGrate™ Spatial Filters (BSF) provides a simple, compact, and cost-effective solution for laser beam spatial filtering. BSF is based on reflecting volume Bragg grating with a narrow acceptance angle that enables filtering of laser beams with a single element, thus replacing pinhole assemblies in case of narrow-line laser sources. In addition to spatial filtering, BSF’s provide ultra-narrow line spectral filtering and can be used for high-power/high-energy applications. BragGrate™ filters have superior environmental stability and can handle high power optical radiation and high operations temperatures.
Specifications
- Diffraction Efficiency (DE): 90-95%
- Spatial Noise Suppression: up to 30 dB
- Center Wavelength Range: 400-2300 nm
- Center Wavelength Tunability (angle tuning): up to 50 nm
- Filter Thickness: 2-5 mm
- Deflection Angles: 5-90 deg
- Lateral Dimensions: up to 25×25 mm2
Standard Parameters
- Center Wavelength: 405, 488, 514, 532, 633, 785, 1064 nm
- Available Custom Wavelengths: 405 nm, 442 nm,
458 nm, 473 nm, 477 nm, 491 nm, 502 nm,
544 nm, 552 nm, 561 nm, 568 nm, 588 nm,
594 nm, 612 nm, 647 nm, 660 nm, 753 nm,
840 nm, 905 nm, 976 nm, 980 nm, 1342 nm, 1352 nm, 1550 nm - Lateral Dimensions: 5×5 mm2
- Thickness: ~3 mm
- Angular Acceptance (FWHM): < 5 mrad
- Deflection Angle: 20 deg
- Aluminum Housing with 0.5” or 1” Outer Diameter
Advantages & Features
- Spacial filtering without refocusing and pinhole assembly
- Highly cost-effective and small footprint
- Easy alignment by angle tuning in standard kinematic mount
- Compatible with high-power operations over 1 kW
- Compatible with high-energy operations up to 5 J/cm2
- Simultaneous spatial and spectral filtering (<5 cm-1 to laser line)
- Supports operation at temperatures up to 400 C
Applications
- Filtering of spatial noise in laser beams
- Ultra-narrow linewidth spectral filtering of laser beams
- ASE filters for diode laser sources
- Wavelength-tunable spatial and spectral filters
Spacial filtering of 632.8 nm HeNe laser with BSF
632.8 nm HeNe laser beam profile before and after BSF cleaning
BragGrate Bandpass/Spatial Filter in a 12.5 mm round holder mounted in a kinematic mount for angle tuning and alignment