Imaging device and method of operating the same

A method of operating an imaging device including a phase adjustment unit, a polarizing plate, a wavelength adjustment unit, a phase difference adjustment unit, and an imaging element, wherein the method comprises:

• matching, by the phase adjustment unit, phases of incident light including a light beam of a first wavelength and a light beam of a second wavelength that are different;
• polarizing, by the polarizing plate, the incident light beams of the first wavelength and the second wavelength into a same polarization direction;
• matching, by the wavelength adjustment unit, a wavelength of the incident light beam of the first wavelength having been polarized by the polarizing plate with a wavelength of the incident light beam of the second wavelength;
• adjusting, by the phase difference adjustment unit, a phase difference to be π, the phase difference being between the incident light beam of the first wavelength and the incident light beam of the second wavelength, the wavelengths of which have been matched by the wavelength adjustment unit;
• and
• simultaneously receiving, by the imaging element, the incident light beam of the first wavelength and the second wavelength having been adjusted by the phase difference adjustment unit such that the phase difference is π,
• wherein the phase difference adjustment unit includes
• a first medium that is transparent and has a predetermined refractive index configured to transmit the incident light beam of the first wavelength, and has a first thickness in a transmission direction, and
• a second medium configured to transmit the incident light beam of the second wavelength, has a same characteristic as that of the first medium, and has a second thickness in the transmission direction, and
• wherein, when the first thickness is known, the second thickness is defined by d2=((1−n2)d1−π)/(1−n2), where d1 is the first thickness, d2 is the second thickness, and n2 is a refractive index of the first medium and the second medium.