Phos-4 precision light source

The Phos-4 is a temperature-clamped, fibre-coupled, precision LED light source. It is intended for fluorescence and transmission measurements, as a precision light source for production and test, and as a controllable light source for general illumination.

The product features a range of user-interchangeable LED modules with wavelengths from 280 to 740 nm. In addition, it can independently control up to four individual dies of a multiwavelength LED, allowing users to combine wavelengths to perform functions such as differential fluorescence measurement or to provide balanced white light sources.

A precision reference controls the linear current drive capable of <1 µs switching at 800 mA. The LED current can be programmed in 0.4 mA steps from 0 to 800 mA and in continuous, PWM or sequencer modes. The precision drive and thermal clamping combine to make a precise optical source with power stability as low as 0.02%/h.

The device has multiple control interfaces: USB and UART interfaces; TTL control or synchronisation signals; and voltage control of the LED current allowing modulation up to 150 kHz. An internal X-Y-Z stage can be used to focus the light to a range of optical fibre connectors, such as SMA or liquid light guides. Filters can be added to the optical path to remove unwanted wavelengths, such as LED substrate fluorescence.