90/10 Beamsplitter Filters0 pages

90/10 Beamsplitter Filters

Ondax’s NoiseBlock™ 90/10 beamsplitter filters are designed to
diffract 90% of the incoming light that matches the designed Bragg
wavelength (λ0) and incident angle. All other wavelengths will be
transmitted through the filter, making them excellent for boosting
the effective signal of a Raman spectrometer.
Adding a NoiseBlock™ 90/10 beamsplitter filter to a Raman spectrometer with a wavelength stabilized laser source can increase
the recovered Raman signal by almost a factor of 4 relative to a
broadband 50/50 beamsplitter.

Features:
• High transmittance at design wavelength
• Narrow spectral bandwidth
• Customizable slant angle for angular
separation of beams
• No degradation under high power
illumination conditions

Applications:
• 90/10 beamsplitter
• Removal of broadband ASE, fluorescence,

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 Raman spectroscopy with high
signal-to-noise.

Specifications:
Parameter

Minimum

Center Wavelength

405

Bandwidth1

Typical

0.03

Diffraction Efficiency

488, 514, 532, 633, 640, 658,
685, 690, 780.25, 785, 808,
830, 976, 1064, 1550
<0.15
<10
90

Temperature Dependence

0.01

Unit

nm
nm (FWHM)
cm-1 (HWHM)
%
nm/ °C

Total Deflection Angle (2θ)

8 - 12

Degrees

Inter-beam Angle (γ)

and unwanted laser line emission

2

Degrees

Clear Aperture Diameter
1

9mm in 1” mount. Custom sizes available

Grating bandwidth is a function of wavlength and thickness

Principle of Operation
NoiseBlock™ 90/10 beamsplitter filters are designed to reflect only the desired single frequency line (λ0)
from a wavelength stabilized laser. The inter-beam angle is chosen to separate the diffracted beam and the
residual surface reflections.
Wavelength Stabilized Laser Diode

Beamsplitter Filter
2θ
Transmitted Light:
λ = λ0: ~10%
λ ≠ λ0: ~100%

Specular Reflection
Diffracted Laser Beam
λ = λ0: ~90%

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