Ondax’s NoiseBlock™ ASE (Amplified Spontaneous Emission) Suppression filters suppress the broad spectrum of spontaneous emission that commonly occurs in laser diodes to provide a pure, ASE free, single frequency laser.
Adding a NoiseBlock™ ASE filter to a single frequency wavelength stabilized laser effectively reduces broadband spectral ASE background to more than 70dB below the laser line while transmitting 90% of the single frequency line. The filter’s narrow spectral profile (HWHM <10cm-1) is designed to match the SureBlock™ Ultra Narrow-band Notch Filter, making it ideal for enabling ultra-low frequency (low wavenumber) Raman spectroscopy with high signal-to-noise.

  • High transmittance at design wavelength
  • Reduce typical broadband ASE levels to more than 70dB below the laser line
  • Narrow spectral bandwidth
  • Customizable slant angle for angular separation of beams
  • No degradation under high power illumination conditions:
  • Environmentally stable at high temperature and humidity with over 12,000 hours of testing at 150°C
  • Fiber coupled input/output available
  • Removal of broadband ASE, fluorescence, and unwanted laser line emission
  • ASE noise reduction for Raman Spectroscopy

Table 1: NoiseBlock™ Specifications
Parameter Min Typ Max Unit
Center Wavelength 405 488, 532, 640, 658, 685, 690, 780.25, 785, 808, 830, 976, 1064, 1500 2700 nm
Bandwidth (FWHM)1 0.03  <0.15<10
Diffraction Efficiency >90 (>70% for 405nm)
Temperature Dependence 0.01 nm/°C
Total Deflection Angle 8-12 Degrees
Inter-beam Angle γ 2 Degrees
Clear Aperture Diameter 4.5mm in 1/2″ mount. Custom sizes available 25 mm

1Grating bandwidth is a function of wavelength and thickness

Technical Data and Drawings
Principles of Operation