NoiseBlock ASE Suppression Filter
NoiseBlock ASE Suppression Filter

NoiseBlock™ ASE Suppression Filter

Coherent’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.

Suppression Filter for ASE-Free, Single Frequency Lasers


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

1Grating bandwidth is a function of wavelength and thickness

Features & Benefits

  • High transmittance at design wavelength
  • Reduce typical broadband ASE levels to more than 70 dB 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

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