Lock-in Amplifiers

Lock-in amplifiers are an essential part of research laboratories in areas such as optics and photonics, nanotechnology and materials science, quantum technologies, scanning probe microscopy and sensing. Thanks to a lock-in amplifier's ability to extract very small signals buried in noise, it is possible to uncover new science and expand the reach of experimental setups. The working principle of a lock-in amplifier, called demodulation or phase-sensitive detection, rests on mixing the measured signal with a reference frequency followed by low-pass filtering.

Choosing the modulation frequency of the measured signal makes it possible to move it away from dominant noise sources – which is especially relevant close to DC. The correct choice of filter settings can further improve the signal-to-noise ratio (SNR).

Our white paper provides a more detailed discussion of lock-in detection.

The Zurich Instruments Lock-in Amplifiers cover 4 frequency ranges

DC to 500 kHz and DC to 5 MHz
with the MFLI Lock-in Amplifier

DC to 50 MHz
with the HF2LI Lock-in Amplifier

DC to 600 MHz
with the UHFLI Lock-in Amplifier

All instruments are equipped with the LabOne^® user interface providing time- and frequency-domain signal analysis tools in the form of a scope, a real-time data plotter, a DAQ module, a spectrum analyzer and a sweeper. Upgrade options include phase-locked loops, PID controllers, multi-demodulator and multi-frequency functionalities, as well as boxcar averagers and arbitrary waveform generators. These options expand the functionalities of the lock-in amplifiers; their installation does not require users to send the instrument back to us, as upgrade options are built on the FPGA-powered digital signal processing unit.

Download the white paper