Optical Choppers

For ordering please see

'How To Order'

Laser Support Services supply a range of opto-mechanical choppers from Avesta, with some models featuring USB control or built-in frequency counters.

Avesta Optical Chopper



The OCV-10kFD opto-mechanical modulator (chopper) is widely used in different optical experiments. It comprises a microprocessor control unit and precise Swiss drive. The device features harmonic and subharmonic generator, sync input and output ports, and PC USB connection.


Frequency range, Hz2-10500

Chopping frequency with 2/100-slot blade*, Hz(2–160) / (50-8000)

Chopping frequency with 10-slot blade, Hz20-1400

Chopping frequency with 60-slot blade, Hz100-8000

Chopping frequency with 100-slot blade**, Hz500-10500

Phase instability peak-to-peak (standard), º3 (0.6)

Phase instability peak-to-peak (standard), at 1 kHz3 (0,6)

Input/output BNC signal levelTTL/CMOS

Internal generator frequency range, Hz0,001 - 1000000

Minimum reference pulse duration, ns45

Phase shift range, º-180 - +180

Phase shift step, º0,1

External frequency range, Hz4 – 1657500

External reference multiplier (harmonics)1-255

External reference divider (subharmonics)1-255

Controller unit dimensions, mm255õ205x85

Power supply voltage 47-63 Hz, V110-220

Power consumption, W<30

* - the blade has 100 slots on external circle and 2 slots – on internal one. The frequency is stabilized on external circle (high frequency), but optical beam is chopped on internal one (low frequency). The phase shift range is from -180° to +180° according to the high frequency (on external circle). 
** - the optical aperture with a 100-slot blade is 1.5 mm


Avesta Optical Chopper



The optical chopper modulates different light sources with given frequency for their subsequent analysis. The built-in frequency counter allows precise selection of the chopping frequency without any external devices.





Frequency range, Hz


Chopping frequency with 2-slot blade, Hz


Chopping frequency with 10-slot blade, Hz


Chopping frequency with 30-slot blade, Hz


Chopping frequency with 60-slot blade, Hz


Chopping frequency with 100-slot blade, Hz


Output sync signal level at BNC connector, V


Frequency setting accuracy, Hz 


Power supply (AC-DC adapter 12V, 0.35 A), V 


Power consumption, W


Dimensions, mm



Avesta Optical Chopper



The joint use of this optical chopper and the lock-in amplifier greatly facilitates low-amplitude signal selection against big background noise.


Frequency range, Hz7-6500

Chopping frequency with 2-slot blade, Hz7-140*

Chopping frequency with 10-slot blade, Hz30-700

Chopping frequency with 30-slot blade, Hz80-2000

Chopping frequency with 60-slot blade, Hz160-4000

Chopping frequency with 100-slot blade, Hz260-6600**

Output sync signal level at BNC connector, V+9

Frequency setting accuracy, Hz 0.5 

Power supply (AC-DC adapter 12V, 0.35 A), V 110-240

Power consumption, W4

Dimensions, mm53*106*144

* - the blade has 100 slots on the outer radius and 2 slots on the inner radius. The modulation of the optical beam is carried out by the inner slots, while the sycnhronization is carried out by the outer slots having the sync frequency 50 times higher than modulation frequency (350-6500 Hz).
** - the clear aperture with this blade is 1.5 mm.