title: Composite infrared bolometers with Si3N4 micromesh absorbers.
abstract: We report the design and performance of 300-mK composite bolometers that use micromesh absorbers and support structures patterned from thin films of low-stress silicon nitride. The small geometrical filling factor of the micromesh absorber provides 20x reduction in heat capacity and cosmic ray cross section relative to a solid absorber with no loss in IR-absorption efficiency. The support structure is mechanically robust and has a thermal conductance, G < 2 x 10(-11) W/K, which is four times smaller than previously achieved at 300 mK. The temperature rise of the bolometer is measured with a neutron transmutation doped germanium thermistor attached to the absorbing mesh. The dispersion in electrical and thermal parameters of a sample of 12 bolometers optimized for the Sunyaev-Zel'dovich Infrared Experiment is +/-7% in R (T), +/-5% in optical efficiency, and +/-4% in G.
authors.affiliation: California Institute of Technology, Mail Stop 59-33, Pasadena, California 91125, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Mauskopf
authors.forename: J J
authors.initials: JJ
authors.lastname: Bock
authors.forename: H
authors.initials: H
authors.lastname: Del Castillo
authors.forename: W L
authors.initials: WL
authors.lastname: Holzapfel
authors.forename: A E
authors.initials: AE
authors.lastname: Lange