What are dichroic mirrors?
Dichroic mirrors known as cold mirrors are commonly used behind a light source to reflect visible light while allowing the invisible infrared light to pass through.
Dichroic mirrors are typically used at AOI 45 degrees. There are short-pass and long-pass mirrors.
- A shortpass mirror is one which has a high transmittance at short wavelengths and high reflectance at longer wavelengths.
- A longpass mirror is one which has high reflectance at short wavelengths and high transmittance at longer wavelengths.
Here is a spectrum of long-pass dichroic mirror:
What specifications are required for a dichroic mirror(dichroic beamsplitter):
- Reflective wavelengths range
- Transmittance wavelengths range
- Edge wavelength
Applications of dichroic mirrors:
- In fluorescence microscopy, dichroic filters/dichroic mirrors are used as beam splitters to direct illumination of an excitation frequency toward to the sample and then pass a particular emission frequency.
- Some LCD projectors use dichroic filters instead of prisms to split the white light from the lamp into the three colours before passing it through the three LCD units.
- Dichroic filters/dichroic mirrors, excitation filters and emission filters form the fluorescence filter set used in fluorescence microscopy.
Dichroic filters/ Dichroic mirrors at Optolong Optics:
- IAD hard coating
- Wavelengths range from UV to infrared
- High reflectance
- High transmittance
- Surface quality 40/20, 60/40
- High precision polished glass substrates