The Agiltron HGDT series of photodetectors have extremely high gain, making us ideal for low-light-level detection applications, such as spectroscopy and fluorescence measurements. We can detect optical signals in the sub-picowatt to 0.5 nanowatt range, and when used with a chopper and lock-in amplifier to reduce the measurement bandwidth, these photodetectors can achieve sensitivity levels in the femtowatt range. We have a 1-mm-diameter PIN photodetector and can detect light from 300 to 1050 nm. The Model 2153 has a 1-mm diameter InGaAs PIN photodetector and operates from 800 to 1700 nm. Typical responsivity curves for the units can be found in the “Responsivity” section on page 24. The circuitry inside the Model 215X consists of a photodetector followed by an electronic gain stage. The incredibly high gain and low-noise performance of our photoreceivers were achieved by careful selection and design of the amplifier-resistor pair. A large feedback resistor is used to achieve the high trans-impedance gain values, while an ultra-quiet amplifier keeps noise to a minimum.
The device is powered by a standard 9V or an external low-noise power supply, which is available for purchase. We have an M4 mounting thread at the bottom.