ELECTRO-OPTICAL PRODUCTS CORPORATION
62-40 Forest Avenue, 2nd Floor • Ridgewood, NY 11385, USA • Tel: 718-456-6000 • Fax: 718-456-6050 • www.eopc.com

Variable Frequency Optical Modulators
CH-40-LS  CH-40-HS
FEATURES AND ADVANTAGES
  • VARIABLE frequency from DC to 30 Hz
  • Low Cost
  • Large aperture
  • Small size/lightweight
  • No radiated electromagnetic interference (EMI)
  • Metal vanes are standard, mirrors, prisms or lenses optional1
1 Available on special order




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optical modulators
resonant choppers
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q switches
pockels cells
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beam deflectors

shutters and filters
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filter selectors
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laser safety shutters
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modulating systems
locked to ext. clock
master/slave mode
a-o systems
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scanners and
deflectors

resonant scanners
polygon scanners
beam deflectors
acousto-optical
peizo scanners

scanning systems
locked to ext. clock
master/slave mode
x,y raster mode
a-o systems

other products
radiometers
photo diode amplifiers
o/e and e/o converters
fiber optic multiplexers
fiber optic video links
laser vibrometers
lock-in amplifiers

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The variable low frequency chopper (optical modulator)/ shutter/ beam deflector is a chopping vane mounted on a motor with a limited rotation angle. The position of the rotor follows the input current with respect to amplitude and frequency. The mechanical rotation of the vane relative to its rest position depends on the direction and the magnitude of the current in the drive coil. The chopper covers a frequency range from DC to 30 Hz. It can hold very large vane, mirror, grating and other optical and electro-optical devices.

The chopper is used when very low frequencies are desired. It is used for large light beam chopping or for simultaneous chopping of multiple optical beams. It is also used as a shutter. If the vane is replaced with a mirror, it is used as an optical beam deflector.

The chopper/ beam deflector/ shutter comes in two versions:
1) The CH-40-LS is a low speed, wide angle chopper
2) The CH-40-HS is a high speed, narrow angle chopper

The LFC driver is used to drive the chopper.

Special configurations and elements other than specified are available as a special order (consult EOPC). Drive electronics with different package, regulation and power supply options are available. Special pricing for OEM applications is also available.

 SPECIFICATION 
 CH-40-LS 
 CH-40-HS 
 MECHANICAL ROTATION 
 24° peak to peak 
 15° peak to peak 
 RESPONSE TIME 
 About 20mSec, depending
on the vane size 
 About 5mSec, depending
on the vane size 
 DRIVE CURRENT SENSITIVITY 
 50mA/degree, ±600mA max. 
 80mA/degree, ±600mA max. 
 DRIVE COIL RESISTANCE 
 7 ohms 
 7 ohms 
 DRIVE COIL INDUCTANCE 
 5mH 
 5mH 
 BACK EMF CONSTANT 
 0.23mV/degree/Sec 
 0.23mV/degree/Sec 

ORDERING INFORMATION:

TYPE [CH-40]; VANE SIZE [mm]; ANGLE [P-P Deg.]
Example: PART NO. CH40-20×30×5-15. This part number specifies the model CH-40 chopper, a 20 × 30mm × 5mm thick vane and a 15° peak to peak angle.


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