| 1. A surveying system, comprising a laser beam projecting device, a projecting optical system for projecting a laser beam
from said laser beam projecting device toward a reflecting object, and a photodetection system having a photodetection element
and for guiding a reflected laser beam from said reflection object toward said photodetection element, wherein said laser
beam projecting device comprises a semiconductor laser light source for emitting a laser beam having a cross-section in an
elliptical shape and having P-polarized light, an anamorphic prism for changing the shape of the cross-section of the laser
beam into a circular shape, a birefringent optical component for converting the P-polarized light to a circularly polarized
light when said laser beam having the P-polarized light transmitted by said anamorphic prism passes through and for converting
the circularly polarized light to S-polarized light when the reflected laser beam having the circularly polarized light passes
through again, and a wavelength selecting film formed on one surface of said anamorphic prism, wherein said anamorphic prism
has a surface tilted in such a manner that an incident angle of the laser beam is in a range of 45° to 80°, and said wavelength
selecting film is formed on said titled surface in such a manner that the incident angle of the laser beam is in a range of
45° to 80°, wherein tilting in a range of 45° to 80° of said wavelength selecting film shifts the transmission wavelength
range of said P-polarized light to the shorter wavelength side than the transmission wavelength range of said S-polarized
light, said wavelength selecting film has a function of a polarization plate to transmit said P-polarized light and to shut
off said S-polarized light at the wavelength range of the shifted amount, and wherein said transmission wavelength range of
said wavelength selecting film is set so as to include the wavelength of the laser beam emitted from said laser light source.
|
