LIA-100 ThorLabs Lock-In Amplifier

The Thorlabs Model LIA100 Lock-In Amplifier is designed to deliver high performance in a compact, cost-effective package. By eliminating some of the less-used features of conventional lock-in amplifiers, the LIA100 offers the performance of units many times its price.

The LIA100 consists of a programmable AC input amplifier, a monolithic phase-sensitive detector (PSD), and a two-stage programmable output low-pass filter. The input amplifier is a two-stage design with an adjustable gain to boost the modulated input. The PSD performs a frequency translation to shift the modulated signal back to its original base band DC. The output filter is a two-stage low pass filter to remove any residual harmonics from the output of the PSD. The output filter has adjustable settings of 10ms, 100ms, 1s, and 3s. In addition, a user-defined time constant can be set by simply adding two capacitors to the LIA100 printed circuit board.

The LIA100 includes a six-position sensitivity control to provide over 60dB of gain adjustment to accommodate a wide range of input signal levels. A monitor output allows the user to monitor the buffered AC amplifier output. A five-position Output Time Constant switch allows the output filter to be set from 10ms to 3s to match the noise and bandwidth of the LIA100 to your signal dynamics (on-board provisions allow a user-specified capacitor to be used for customizing the output filter). A 10X output expand allows the output to be amplified by a factor of 10 (20dB) for optimizing the output signal level for specific data acquisition systems.

Note: The principal advantage of lock-in amplifiers is that all non-synchronous noise (i.e. noise components which are out of phase with the modulated signal) is suppressed by the PSD. This results in a signal-to-noise improvement of many orders of magnitude.