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Liquid Crystal Noise Eater / Laser Stabilizer


Noise Eaters / Laser Amplitude Stabilizers

  • Laser Amplitude Stabilizer/ Variable Attenuator
  • Models with Wavelength Ranges Covering 425 - 1620 nm Available
  • Closed-Loop Feedback System


  • Reduces Laser Intensity Noise
  • Also Functions as a Variable Attenuator or EO Modulator
  • Models for use at 425 - 650 nm, 475 - 650 nm, 650 - 1050 nm, 650 - 1100 nm, or 1050 - 1620 nm
  • Maximum Input Power of up to 1 W, Depending on Model, Wavelength, and Beam Size
    (See the Operation Tab for Details)
  • Excellent for Sensitive Experiments such as Optical Tweezers
  • Ideal for Stabilizing CW Pump Lasers

Thorlabs’ Liquid Crystal Noise Eaters / Laser Amplitude Stabilizers are precision instruments for stabilizing, modulating, and attenuating the power of linearly polarized light. These closed-loop systems are designed for use with light in the 425 - 650 nm (LCC3111 and LCC3111L), 475 - 650 nm (LCC3111H), 650 - 1050 (LCC3112H), 650 - 1100 nm (LCC3112), or 1050 - 1620 nm (LCC3113 and LCC3113H) wavelength range. We offer noise eater models for low (Specs tab for details.

Noise Reduction
Utilizing a liquid crystal amplitude modulator, combined with a photodiode for power measurement and a feedback control circuit, the noise eaters can eliminate intensity noise in linearly polarized light, achieving amplitude stabilization of within 0.05% of a selected output power. The input power can be set to one of several ranges using the switch(es) on the top of the unit. The potentiometer is then adjusted to select the output power.

Power Attenuation and Modulation
These noise eaters are also capable of continuously attenuating and modulating the laser output using the liquid crystal retarder and integrated polarizer. Unlike most attenuators available, Noise Eaters attenuate the laser power rapidly without the use of any mechanical components. The noise eater’s attenuation capabilities can be controlled via the onboard potentiometer or electrical modulation input (only certain noise eater models have modulation capabilities; see the Specs tab for details).

Thorlabs’ Noise Eaters are post mountable in two orientations via 8-32 (M4) tapped holes. They also feature 4-40 tapped holes on the front and back for 30 mm Cage System compatibility and an SM1-threaded (1.035"-40) rear aperture for Ø1" Lens Tube compatibility.


Noise Eaters Product Line Overview
Item # LCC3111L LCC3111H LCC3111 LCC3112H LCC3112 LCC3113H LCC3113
Modulation Input      
Low Power Operation Only      
High Power Operation Only            
Switchable Low/High
Power Operation

Noise Eaters with Modulation Input

Item #LCC3111L(/M)LCC3111H(/M)LCC3112H(/M)LCC3113H(/M)
Wavelength Range 425 - 650 nm 475 - 650 nm 650 - 1050 nm 1050 - 1620 nm
Noise Attenuation Performance Specs
Output Power Stabilitya ±0.05%
Noise Attenuation Frequency Range DC - 1.8 kHz DC - 2.5 kHz DC - 1.4 kHz
Noise Attenuation Amplitude Range 0.1% to 50% of Input Signal
Noise Attenuation Factorb >100 at 10 Hz, 40 at 60 Hz
10 at 400 Hz, 4 at 1 kHz
>150 at 10 Hz, 80 at 60 Hz
10 at 400 Hz, 1.5 at 1 kHz
Output Power Attenuation Factor Rangec 1 - 40 1 - 5
Internal Polarizer Blocking Damage
Threshold (Maximum Power Attenuation)
1 W/cm2 10 W/cm2
Attenuation Control Onboard Potentiometer (10 Turns) or Modulation Input
Optical Specs
Transmission (Click for Plot) >85% at 650 nm >80% at 635 nm >85% at 780 nm  >85% at 1550 nm
Power Level Switching Four Position Power Range Switch Three Position Power Range Switch High/Low Power Mode Switch and Four Position Power Range Switch
Maximum Input Power See the Max Powers at Various Wavelengths section on the Operation tab
Minimum Input Power 0.5 mW 50 mW 0.5 mW
Damage Threshold (CW)d 0.8 W/cm2 8 W/cm2
Input Aperture Ø5 mm
Input Beam Diameter Ø4 mm (Max)e
Output Beam Displacement 1 mm Vertically (in the Direction of Input Polarization)
Beam Divergence 5 mrad (Max)
Angle of Incidence ±2° (Max)
Input Polarization Tolerance ±3°
Wavefront Distortion ≤λ/4 at 635 nm ≤λ/2 at 635 nm ≤λ/2 at 635 nm
AR Coating Ravg <0.5% from 400 - 650 nm Ravg <0.5% from 650 - 1100 nm Ravg <0.5% from 1050 - 1620 nm
Modulation Performance Specs
Modulation Input SMC Connector, 0 - 2.5 V, 10 kΩ Input Impedance
Minimum Extinction Ratiof 512.6 7.7 6.5
Minimum Rise / Fall Timeg 0.65 ms / 7.3 ms 0.75 ms / 11.5 ms 2.8 ms / 25 ms
General Specs
Mounting Options Two 8-32 (M4) Tapped Holes for Post Mounting
30 mm Cage System Compatible
Ø1" Lens Tube Compatible
Operating Temperature Range 15 °C to 45 °C
  • RMS value over 8 hours
  • Noise attenuation factor is the ratio of noise amplitude before and after the noise eater. Tested at 100 mW input power with a noise amplitude of 5% of the input power level. See detailed noise attenuation plots on the Performance tabs for more information.
  • Range of output power adjustment for a given input power level
  • Max input power density and laser damage threshold are wavelength-independent. Additionally, the absolute maximum input power varies with wavelength; see the Operation tab for details.
  • Specified for a 1/e2 beam diameter
  • Extinction ratio is the ratio of the signal power at minimum attenuation to the signal power at full attenuation.
  • Rise time is measured on the rising edge of the output intensity from 10% to 90% of full output power.

Noise Eaters for 425 - 620 nm or 475 - 650 nm

* LCC3111L is a Low-Power Noise Eater (0.5 mW to 60 mW) with a Modulation Input
* LCC3111H is a High-Power Noise Eater (50 mW to 1000 mW) with a Modulation Input
* LCC3111 is a Low-Power Noise Eater (0.5 mW to 60 mW) without a Modulation Input

Noise Eaters for 650 - 1050 nm or 650 - 1100 nm

* LCC3112H is a Switchable Low/High-Power Noise Eater (0.5 mW to 60 mW and 50 mW to 1000 mW) with a Modulation Input
* LCC3112 is a Low-Power Noise Eater (0.5 mW to 100 mW) without a Modulation Input

Noise Eaters for 1050 - 1620 nm

* LCC3113H is a Switchable Low/High-Power Noise Eater (0.5 mW to 57.6 mW and 50 mW to 835 mW) with a Modulation Input
* LCC3113 is a Low-Power Noise Eater (0.5 mW to 57.6 mW) without a Modulation Input



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