O-VARM Optical Attenuator

Product Description

• Attenuating optical module for laser observation with cameras.
• Enables easy control and adjustment of the output power of fixed-power lasers.
• Specifically designed for use with the BeamTester beam analysis system.
• Delivers nearly distortion-free and interference-free attenuation.
• Features continuously variable attenuation ratio; suitable for beams up to 1 W/cm²or 1 J/cm².
• Can be directly mounted to cameras via a C-Mount adapter.

The O-VARM variable optical attenuator is an easy-to-use device that provides continuous attenuation of laser output power. It offers an attenuation range from 107:1 to 3000:1 with fine adjustment capability to achieve precise attenuation levels and fully utilize the optical dynamic range of the camera.

 

Model	O-VARM
Wavelength Range	380–2200 nm
Attenuation Range	107:1 to 3000:1
Clear Aperture	Ø15 mm
Thread Type	SM1 (1.035”-40) thread, C-Mount (1.00”-32) thread
Max Power Density	1 W/cm²
Max Energy Density	1 J/cm²
Dimensions	63.1 × 45.7 × 55.7 mm
Note	The listed maximum power and energy density levels refer to the threshold for thermal lensing effects.

Technical Notes

 

In most camera-based systems, laser beam power must be attenuated before feeding into the beam analyzer. Conventional technologies often fail to provide continuous control of laser power. The O-VARM variable optical attenuator solves this problem: it integrates two continuously variable wedge attenuators and one step attenuator, supporting a 107:1 to 3000:1 attenuation range. Fine tuning allows precise attenuation settings to maximize the camera’s optical dynamic range.

When stacking multiple filters for cascaded attenuation, beam distortion must be avoided. Typically, cameras cannot detect total beam distortion below ~λ/4. The wavefront distortion introduced by multiple optical filters can be calculated as the square root of the sum of the squares of the wavefront distortion of each component.

Example: If a single optical element is specified at λ/10 and 6 elements are used, the total wavefront distortion of the beam is λ/4 RMS.

The attenuator housing features internal SM1 (1.035”-40) and C-Mount threads, allowing direct connection of beam cameras, microscope objectives, and extension tubes to form a flexible close-up imaging system for analyzing small beams, focused beams, optical fibers, laser diodes, or LEDs. Additionally, the base of the attenuator is equipped with M6 mounting holes for standalone installation on stainless steel posts.

Assembly

Application Examples

Engineering Drawings

O-VARM Engineering Drawing