Mechanical strength and millimeter-wave transmittance spectrum of stacked sapphire plates bonded by sodium silicate solution

Takayuki Toda, Yuki Sakurai, Hirokazu Ishino +3

The polarization modulator unit for the low-frequency telescope in LiteBIRD employs an achromatic half-wave plate (AHWP). It consists of five layers of a-cut sapphire plate, which…