474
E. Hasman and V. Kleiner
SLM
Laser
BS
Element
To
Camera
Focusing
lens
2 μm
Spiral Phase
(a)
(b)
in =- 1
in =1
σ
σ
Fig. 13.7 The removal of the spin-degeneracy in circular corrugation by use of externally induced
OAM. a Experimental setup. A laser beam is modulated by a spatial light modulator (SLM) to obtain
a spiral phase and then incident through a beam splitter (BS) onto a coaxial aperture with circular
corrugation. The transmitted light is captured in the image plane by the camera. The spiral phase
with l ext = 2, the measured intensity distribution across the incident beam, and the SEM picture
of the element are presented in the figure. b Intensity distribution cross-sections captured by the
camera for different l ext . The blue dashed lines correspond to |λ + ≈ illumination and red solid lines
correspond to |λ − ≈ illumination. The intensity is normalized by the transmission measured via a
annular aperture without the surrounding corrugation (the horizontal dimension is scaled according
to the optical magnification). Reprinted with permission from Ref. [34]. Copyright 2009 American
Chemical Society
gating it to the far-field and it was done in experiment (see Fig. 13.8b–e). As expected
from the far-field of E G M
r , a bright and a dark spot have been observed for the left and
right circular polarization components, respectively, with a good agreement between
calculation and measurement. Thus, the total AM of light in the system is conserved
also for the scattered light ( j = 1).
E. Hasman and V. Kleiner
SLM
Laser
BS
Element
To
Camera
Focusing
lens
2 μm
Spiral Phase
(a)
(b)
in =- 1
in =1
σ
σ
Fig. 13.7 The removal of the spin-degeneracy in circular corrugation by use of externally induced
OAM. a Experimental setup. A laser beam is modulated by a spatial light modulator (SLM) to obtain
a spiral phase and then incident through a beam splitter (BS) onto a coaxial aperture with circular
corrugation. The transmitted light is captured in the image plane by the camera. The spiral phase
with l ext = 2, the measured intensity distribution across the incident beam, and the SEM picture
of the element are presented in the figure. b Intensity distribution cross-sections captured by the
camera for different l ext . The blue dashed lines correspond to |λ + ≈ illumination and red solid lines
correspond to |λ − ≈ illumination. The intensity is normalized by the transmission measured via a
annular aperture without the surrounding corrugation (the horizontal dimension is scaled according
to the optical magnification). Reprinted with permission from Ref. [34]. Copyright 2009 American
Chemical Society
gating it to the far-field and it was done in experiment (see Fig. 13.8b–e). As expected
from the far-field of E G M
r , a bright and a dark spot have been observed for the left and
right circular polarization components, respectively, with a good agreement between
calculation and measurement. Thus, the total AM of light in the system is conserved
also for the scattered light ( j = 1).