DET50B In Stock

The ThorLabs DET50B is a top-of-the-line Germanium (Ge) detector engineered to detect light signals within a wide range of 800 to 1800 nm. Enclosed in rugged aluminum housing, the DET50B comprises a photodiode and internal 12 V bias battery, providing a reliable and durable solution for monitoring both fast pulsed lasers and DC optical sources. The DET50B's removable 1” optic coupler allows for easy mounting of accessories such as fiber adapters, spectral filters, and ND filters, thanks to its simple yet efficient design. The DC-coupled output ensures a wide bandwidth, making the DET50B ideal for various applications that demand high precision and accuracy.

The DET50B features a special junction photodiode that functions similarly to a traditional signal diode but will produce a photocurrent when exposed to light in the semiconductor junction depleted region. This fast and highly linear device exhibits high quantum efficiency and can be used in a variety of different applications. The photodiode of the DET50B can operate in either photovoltaic (zero-bias) or photoconductive (reverse bias) mode, depending on the speed requirements of the application and the tolerable dark current amount.

When the DET50B is utilized in photoconductive mode, an external reverse bias is put in place to enlarge the depletion junction width. This leads to a greater sensitivity with a decreased capacitance junction, creating an impressively linear response. When the photodiode is operated in photovoltaic mode, it is not biased and a restriction in the current flowing out of it leads to an increase in voltage. This system takes advantage of the photovoltaic effect, which is what solar cells are built upon.

The DET50B is designed with user convenience in mind, as it features a red button that applies the battery's voltage across the external load, making it easy to determine if the battery needs to be replaced. The unit also includes an in-line current-limiting resistor (1.05 kΩ) that prevents fast battery drainage if the battery is tested while connected to a 50 Ω load. Furthermore, the battery check feature allows the user to monitor the bias voltage on the output BNC with a V Bias Out button located on the bottom edge of the unit.