O-VACM Variable Optical Attenuator

Product Description

• Attenuation optical assembly for laser observation with cameras.
• Easy to control and adjust the output power of fixed-power lasers.
• Designed specifically for use with the BeamTester beam analysis system.
• Nearly distortion-free and interference-free attenuation.
• Continuously variable attenuation ratio, suitable for beams up to 1 W/cm² or 1 J/cm².
• Directly connectable to cameras via a C-Mount adapter.

The O-VACM variable optical attenuator is an easy-to-use device for continuous attenuation of laser output power. The continuously variable attenuation module contains two continuously variable wedge attenuators, with an attenuation range from 123:1 to 65800:1.

 

Item	Specification
Model	O-VACM
Wavelength Range	380–2200 nm
Attenuation Range	123:1 to 65800:1
Clear Aperture	Ø12.7 mm
Thread Type	SM05 (0.535”-40) internal thread; 2×M4 holes
Cage Compatibility	4×Ø6.05 mm through holes, 30 mm spacing
Max Power Density	1 W/cm²
Max Energy Density	1 J/cm²
Dimensions	90.0×58.0×27.0 mm (knob excluded)
Note	Listed max power and energy densities correspond to the onset of thermal lensing

Technical Description

 

In most camera-based systems, the laser beam power must be attenuated before it enters the beam analyzer. Conventional methods often cannot provide continuous control of laser power. The O-VARM variable optical attenuator is an easy-to-use device that enables continuous attenuation of laser output power. The module includes two continuously variable wedge attenuators and one step attenuator, with an attenuation range from 107:1 to 3000:1. Fine adjustment is available to achieve precise attenuation levels and maximize the camera’s optical dynamic range.

When stacking multiple filters for attenuation, beam distortion must be minimized. Typically, cameras cannot resolve total beam distortion below ~λ/4. The wavefront distortion from multiple optical filters is calculated as the square root of the sum of the squares of the distortion from each element. For example, if a single element is rated at λ/10 and 6 elements are used, the total wavefront distortion is λ/4 RMS:√[(1/10)² × 6] ≈ 0.25 (λ/4)

The attenuator housing features an SM05 (0.535”-40) internal thread for mounting filters or lens tubes. Four through holes on the faceplate are compatible with PCM-series cage rods for easy integration into 30 mm cage systems. Two M4 threaded holes on the side of the housing are provided for mounting posts.

Assembly

Application Examples

Engineering Drawings

O-VACM Engineering Drawing