Astronomical dichroic mirror plays an important role to observe the multiple colors simultaneously and effectively, especially in GRB observation.
Dichroic mirror determines the total optical performance of camera such as separation of each spectral band or imaging quality. That is, the dichroic is definitely one of the key components in your camera. Therefore, unprecedented specifications are always required for astronomical dichroic mirror compared to other applications.
In addition, the beam on the dichroic becomes ellipsoidal shape due to the angle of incidence, so large clear aperture is often requested.
Asahi is currently developing the astronomical dichroic mirror which can meet the requirements as above simultaneously for optical wavelength as well as IR.