A blue-reflecting, green-transmitting dichroic mirror is an optical interference-based filtering device. Its core function is to selectively reflect blue wavelengths of light while transmitting others (such as green light). It is achieved through precise multilayer thin-film coating technology, where the thickness and refractive index of each layer are optimized to enhance the reflection or transmission efficiency of target wavelengths using optical interference effects.

Features and Advantages
High wavelength selectivity: Reflects blue light (e.g., 400-500 nm) while efficiently transmitting green light (500-600 nm), with a spectral efficiency of over 90%.
Low absorption loss: Relies on interference rather than dye absorption, reducing optical energy loss and thermal effects, making it suitable for high-power laser systems.

Wide range of applications: Commonly used in fluorescence microscopy, laser beam splitting systems, projectors, and other equipment to achieve multi-wavelength separation or synthesis.
Technical Parameters
Angle of incidence: Typically designed at 45°, but can be adjusted according to requirements.
Durability: Hard coatings resist environmental oxidation, offering a longer lifespan than traditional filters.

The curve is as follows: