  We present the detailed design of the near infrared camera for the SuMIRe
(Subaru Measurement of Images and Redshifts) Prime Focus Spectrograph (PFS)
being developed for the Subaru Telescope. The PFS spectrograph is designed to
collect spectra from 2394 objects simultaneously, covering wavelengths that
extend from 380 nm - 1.26 um. The spectrograph is comprised of four identical
spectrograph modules, with each module collecting roughly 600 spectra from a
robotic fiber positioner at the telescope prime focus. Each spectrograph module
will have two visible channels covering wavelength ranges 380 nm - 640 nm and
640 nm - 955 nm, and one near infrared (NIR) channel with a wavelength range
955 nm - 1.26 um. Dispersed light in each channel is imaged by a 300 mm focal
length, f/1.07, vacuum Schmidt camera onto a 4k x 4k, 15 um pixel, detector
format. For the NIR channel a HgCdTe substrate-removed Teledyne 1.7 um cutoff
device is used. In the visible channels, CCDs from Hamamatsu are used. These
cameras are large, having a clear aperture of 300 mm at the entrance window,
and a mass of ~ 250 kg.
  Like the two visible channel cameras, the NIR camera contains just four
optical elements: a two-element refractive corrector, a Mangin mirror, and a
field flattening lens. This simple design produces very good imaging
performance considering the wide field and wavelength range, and it does so in
large part due to the use of a Mangin mirror (a lens with a reflecting rear
surface) for the Schmidt primary. In the case of the NIR camera, the rear
reflecting surface is a dichroic, which reflects in-band wavelengths and
transmits wavelengths beyond 1.26 um. This, combined with a thermal rejection
filter coating on the rear surface of the second corrector element, greatly
reduces the out-of-band thermal radiation that reaches the detector.
