S121C In Stock

The S121C by ThorLabs is a photodiode power sensor, the perfect solution for general measurements of optical power. Ideal for incoherent and low power coherent sources from the ultraviolet to the near-infrared range, the S121C boasts a range of impressive features to ensure accurate and reliable measurements. Featuring a large Ø9.5 mm sensor aperture and an integrated viewing target for easy alignment, the S121C is compatible with SM1 (1.035"-40) lens tubes and Ø1/2" posts, making it suitable for both fiber-coupled and free-space sources. It can also be mounted in a 30 mm cage system using a compatible 30 mm cage system optic mount with internal SM1 threading.

Designed for maximum efficiency, the S121C is optimized for a small thickness, allowing it to fit into tight spaces with ease. With its high-sensitivity photodiode and large active area, along with a reflective diffused ND filter, this power sensor has the capability to measure power up to 500 mW in both free-space and fiber applications. Moreover, a removable annular VIS/IR viewing target makes it easy to center the measured beam to the active area of the photodiode. The target absorbs light from 400 to 640 nm and 800 to 1700 nm.

The S121C's housing includes a threaded input in axis with the light input aperture, compatible with 1" threaded accessories, which enables convenient mounting of light filters, fiber adapters, apertures, and external optics. Additionally, it is compatible with a set of fiber adapters to connect the power sensor to standard optical fiber patch cables. The S121C's enhanced shielding protects against electromagnetic interference, ensuring accurate measurements every time. The sensor also features an alert system that warns against any damage or errors caused due to excess heat. This protects the sensor and ensures accurate measurements.