This Optical Chopper is a precision instrument that utilizes advanced features to modulate light from a continuous beam. The controller uses a phase-locked loop (PLL) motor speed control design to precisely maintain the chopping speed and phase relative to a reference signal. An internal, crystal-stabilized, frequency synthesizer provides an accurate and stable reference frequency for stable long-term performance. This Chopper offers faster locking times, interface improvements, and a larger selection of blades than our previous-generation Optical Chopper.
An optical switch is used to get the reference signal when the chopper blades pass through and interrupt the beam path. The switch incorporates an LED with a wavelength range of 850 nm - 940 nm that is operated at the 15 mA threshold current to minimize light output from the LED.
The design features a high quality, rare earth magnet, DC motor. The photo-etched optical chopper wheel blade is made of 0.01" thick blued clock spring steel for high precision. The compact optical head has a wide base for extra stability, and the base is slotted for two 1/4"-20 (M6) mounting screws on 3" (76.2 mm) centers. The mounting slots have a 1.5" (38.1 mm) radius. The interface cable uses circular snap-on Hirose connectors for easy setup.
The controller includes a 240 x 128 pixel graphics display for setting and monitoring chopper functionality. All of the functions are accessible through a front panel control knob with turn and push control. Multiple user setups can be easily saved and recalled from non-volatile memory. A USB interface is included as a standard feature for remote PC control of this optical chopper.
Technical Specifications:
- 20 Hz - 10kHz Chopping Frequency (with default blade)
- < 20 ppm/°C Frequency Drift
- 0.1 Hz Frequency Resolution
- Zero Gauss chamber for checking and correcting probe offset
- Full-range calibration on the 0.1 T, 0.5 T, 3 T, and 20 T ranges
- 20 T measurement range calibrated up to 3 T
Features:
- Crystal-Stabilized, Phase-Locked Feedback Loop Suppresses Low Frequency Drift and Phase Jitter
- Harmonic, Subharmonic, and Fractional Harmonic Chopping with Sum and Difference Reference Outputs
- Microprocessor Controlled
- Single- and Dual-Frequency Blades Available
- Harmonic Frequency Blades Available for Pump-Probe and Other Nonlinear Experiments
- Save and Recall User Setups in Non-Volatile RAM
- USB Interface
