Low noise laser driver lowers detection threshold

16th January 2015

Barney Scott

0 0

Datasheet

Electronic noise from Quantum Cascade Laser drivers has long limited the detection threshold of chemical sensors. Addressing this issue, patented low noise technology is available to both researchers and developers as Wavelength introduces the QCL LAB family. These instruments couple a touchscreen display with low noise drive electronics that drop detection thresholds up to an order of magnitude.

Quantum Cascade Lasers (QCLs) operate with high power at wavelengths suited to detecting molecules significant to humans. Some applications include remote detection of explosive materials, medical diagnosis using the breath, non-invasive glucose testing, emissions & air quality monitoring, petroleum leak detection and methane detection in fracking. The list is growing exponentially as researchers discover novel possibilities.

Detection threshold is always a defining characteristic of a sensor. With 0.4μA RMS noise current and 1nA/√Hz average current noise density up to 100kHz, the QCL500 LAB instrument allows the lowest possible detection thresholds. Low electronic noise translates into stable centre wavelength, narrow linewidth, and repeatable scans.

Safety features include adjustable soft-clamp current limit with Brick-Wall Never-Exceed circuitry, password protection for locking out a selectable control set, key switch, active and passive interlocks. Driver over-temperature protection as well as AC input and power supply filtering are provided. The relay shorts output when current is disabled, and an adjustable 2 second turn-on delay is offered alongside a 1.5ms current ramp.

Models are available with output currents of 500, 1000, 1500, and 2000mA in Constant Current mode. Compliance voltage is adjustable up to 20V with 2-3MHz analogue modulation bandwidth. Operation is standalone or via USB or Ethernet (remote operation software included).

Application notes and free technical support are offered to help designers minimise noise in particularly demanding applications. After testing is complete, compact OEM drivers are available for integration into field-deployable systems.