68-402 12.5 x 17.5 mm 60:40 (R:T) N-BK7 Plate Beamsplitter; t=3mm NIR 700-1100nm

The 68-402 is a high-quality beam splitter from Edmund Optics, designed for use in the near-infrared (NIR) spectrum, specifically between 700 and 1100nm. This beam splitter is rectangular in shape, with dimensions of 12.5 x 17.5 mm, and has a thickness of 3mm.

The beam splitter is made from N-BK7 glass, a popular material in optical systems due to its excellent optical properties and high damage threshold. The N-BK7 Schott designation indicates that this glass meets the rigorous standards set by Schott, a leading manufacturer of optical glass.

The beam splitter features a 60:40 (R:T) split ratio, meaning that 60% of the incident light is reflected, while 40% is transmitted. This split ratio is achieved through the application of a specialized coating, EDM 68-400, to the front surface of the beam splitter. This coating is specifically designed for use in the NIR spectrum, ensuring optimal performance in this wavelength range.

The beam splitter is designed in the shape of a thin lens, which can be beneficial in certain optical systems due to its reduced thickness and weight. This can help to minimize aberrations and improve the overall performance of the system.