SR542 — Low Jitter Optical Chopper

Frequency range from 0.4 Hz to 20 kHz

Flexible synchronization

Low phase jitter

0.01° phase resolution

20 ppm frequency accuracy

Long-life brushless motor

USB computer interface

The SR542 Precision Optical Chopper provides ultra-stable and flexible optical chopping. The chopping frequency is adjustable over a wide range and can be controlled from various input sources, including synchronization with an external reference. The front panel offers an intuitive view of the entire configuration at a glance, while remote USB communication allows full control from a remote PC.

Optical choppers provide a straightforward method for modulating lasers. The SR542 Precision Optical Chopper offers enhanced functionality and configurability along with optimized chopping performance. Whether your application requires best-in-class phase jitter performance, tracking an external reference voltage, a wide frequency range, dual-wavelength mixing, or synchronizing multiple choppers, the SR542 will get the job done.

Flexible Configuration

The chopper can be synchronized with various input sources, including external frequency references (sine wave or TTL/CMOS), internal clock (crystal oscillator), VCO input (0 to +10 VDC), or AC line (50 Hz to 60 Hz). Long-term frequency drift is virtually eliminated. Chopping rates as low as 0.4 Hz or as high as 20 kHz can be achieved (depending on the blade).

User-programmable multipliers and dividers enable harmonic chopping rates, subharmonics, or fractional harmonics of the primary frequency.

Users can select internal slot, external slot, or shaft (one pulse per revolution) to phase-lock to a scaled master reference. Phase offset is easily adjustable with a resolution of 0.01°, and relative phase can be set to a zero-phase reference.