  We have conducted a systematic near-infrared circular polarization (CP)
survey in star-forming regions, covering high-mass, intermediate-mass, and
low-mass young stellar objects. All the observations were made using the SIRPOL
imaging polarimeter on the Infrared Survey Facility 1.4 m telescope at the
South African Astronomical Observatory. We present the polarization properties
of ten sub-regions in six star-forming regions. The polarization patterns,
extents, and maximum degrees of linear and circular polarizations are used to
determine the prevalence and origin of CP in the star-forming regions. Our
results show that the CP pattern is quadrupolar in general, the CP regions are
extensive, up to 0.65 pc, the CP degrees are high, up to 20 %, and the CP
degrees decrease systematically from high- to low-mass young stellar objects.
The results are consistent with dichroic extinction mechanisms generating the
high degrees of CP in star forming regions.
